Health and Human Services Secretary Robert F. Kennedy Jr. has long been a critic of the vaccine court, calling it "biased" against compensating people, slow and unfair. He has said that he wants to "revolutionize" or "fix" this system.

I'm a scholar of law, health and medicine. I investigated the history, politics and debates about the Vaccine Injury Compensation Program in my book "Vaccine Court: The Law and Politics of Injury."

Although vaccines are extensively tested and monitored, and are both overwhelmingly safe for the vast majority of people and extremely cost-effective, some people will experience a harmful reaction to a vaccine. The vaccine court establishes a way to figure out who those people are and to provide justice to them.

Having studied the vaccine court for 15 years, I agree that it could use some fixing. But changing it dramatically will be difficult and potentially damaging to public health.

Deciphering vaccine injuries

The Vaccine Injury Compensation Program is essentially a process that enables doctors, lawyers, patients, parents and government officials to determine who deserves compensation for a legitimate vaccine injury.

It was established in 1986 by an act of Congress to solve a specific social problem: possible vaccine injuries to children from the whole-cell pertussis vaccine. That vaccine, which was discontinued in the U.S. in the 1990s, could cause alarming side effects like prolonged crying and convulsions. Parents sued vaccine manufacturers, and some stopped producing vaccines.

Congress was worried that lawsuits would collapse the country's vaccine supply, allowing diseases to make a comeback. The National Childhood Vaccine Injury Act of 1986 created the vaccine court process and shielded vaccine manufacturers from these lawsuits.

Here's how it works: A person who feels they have experienced a vaccine-related injury files a claim to be heard by a legal official called a special master in the U.S. Court of Federal Claims. The Health and Human Services secretary is named as the defendant and is represented by Department of Justice attorneys.

Doctors who work for HHS evaluate the medical records and make a recommendation about whether they think the vaccine caused the person's medical problem. Some agreed-upon vaccine injuries are listed for automatic compensation, while other outcomes that are scientifically contested go through a hearing to determine if the vaccine caused the problem.

Awards come from a trust fund, built up through a 75-cent excise tax on each dose of covered vaccine sold. Petitioners' attorneys who specialize in vaccine injury claims are paid by the trust fund, whether they win or lose.

Some updates are needed

Much has changed in the decades since Congress wrote the law, but Congress has not enacted updates to keep up.

For instance, the law supplies only eight special masters to hear all the cases, but the caseload has risen dramatically as more vaccines have been covered by the law. It set a damages cap of US$250,000 in 1986 but did not account for inflation. The statute of limitations for an injury is three years, but in my research, I found many people file too late and miss their chance.

When the law was written, it only covered vaccines recommended for children. In 2023, the program expanded to include vaccines for pregnant women. Vaccines just for adults, like shingles, are not covered. COVID-19 vaccine claims go to another system for emergency countermeasures vaccines that has been widely criticized. These vaccines could be added to the program, as lawyers who bring claims there have advocated.

These reform ideas are "friendly amendments" with bipartisan support. Kennedy has mentioned some of them, too.

A complex system is hard to revolutionize

Kennedy hasn't publicly stated enough details about his plan for the vaccine court to reveal the changes he intends to make. The first and least disruptive course of action would be to ask Congress to pass the bipartisan reforms noted above.

But some of his comments suggest he may seek to dismantle it, not fix it. None of his options are straightforward, however, and consequences are hard to predict.

Straight up changing the vaccine court's structure would probably be the most difficult path. It requires Congress to amend the 1986 law that set it up and President Donald Trump to sign the legislation. Passing the bill to dismantle it requires the same process. Either direction involves all the difficulties of getting a contentious bill through Congress. Even the "friendly amendments" are hard — a 2021 bill to fix the vaccine court was introduced but failed to advance.

However, there are several less direct possibilities.

Adding autism to the injuries list

Kennedy has long supported discredited claims about harms from vaccines, but the vaccine court has been a bulwark against claims that lack mainstream scientific support. For example, the vaccine court held a yearslong court process from 2002 to 2010 and found that autism was not a vaccine injury. The autism trials drew on 50 expert reports, 939 medical articles and 28 experts testifying on the record. The special masters deciding the cases found that none of the causation hypotheses put forward to connect autism and vaccines were reliable as medical or scientific theories.

Much of Kennedy's ire is directed at the special masters, who he claims "prioritize the solvency" of the system "over their duty to compensate victims." But the special masters do not work for him. Rather, they are appointed by a majority of the judges in the Court of Federal Claims for four-year terms — and those judges themselves have 15-year terms. Kennedy cannot legally remove any of them in the middle of their service to install new judges who share his views.

Given that, he may seek to put conditions like autism on the list of presumed vaccine injuries, in effect overturning the special masters' decisions. Revising the list of recognized injuries to add ones without medical evidence is within Kennedy's powers, but it would still be difficult. It requires a long administrative process with feedback from an advisory committee and the public. Such revisions have historically been controversial, and are usually linked to major scientific reviews of their validity.

Public health and medical groups are already mobilized against Kennedy's vaccine policy moves. If he failed to follow legally required procedures while adding new injuries to the list, he could be sued to stop the changes.

Targeting vaccine manufacturers

Kennedy could also lean on his newly reconstituted Advisory Committee on Immunization Practices to withdraw recommendations for certain vaccines, which would also remove them from eligibility in the vaccine compensation court. Lawsuits against manufacturers could then go straight to regular courts. On Aug. 14, 2025, the Department of Health and Human Services may have taken a step in this direction by announcing the revival of a childhood vaccine safety task force in response to a lawsuit by anti-vaccine activists.

Kennedy has also supported legislation that would allow claims currently heard in vaccine court to go to regular courts. These drastic reforms could essentially dismantle the vaccine court.

People claiming vaccine injuries could hope to win damages through personal injury lawsuits in the civil justice system instead of vaccine court, perhaps by convincing a jury or getting a settlement. These types of settlements were what prompted the creation of the vaccine court in the first place. But these lawsuits could be hard to win. There is a higher bar for scientific evidence in regular courts than in vaccine court, and plaintiffs would have to sue large corporations rather than file a government claim.

Raising the idea of reforming the vaccine court has provoked strong reactions across the many groups with a stake in the program. It is a complex system with multiple constituents, and Kennedy's approaches so far pull in different directions. The push to revolutionize it will test the strength of its complex design, but the vaccine court may yet hold up.

This edited article is republished from The Conversation under a Creative Commons license. Read the original article.

Her clients find themselves too thin, and they're suffering. "Last week, I signed up a client who wears leggings that have bum pads in them," says Barnes, who lives in Great Britain. "I've had another client recently that, in summer, wears three pairs of leggings just to try and make herself look a bit bigger."

These women belong to a demographic group that has been widely overlooked. As the world focuses on its billion-plus obese citizens, there remain people at the other end of the spectrum who are skinny, often painfully so, but don't want to be. Researchers estimate that around 1.9 percent of the population are "constitutionally thin," with 6.5 million of these people in the United States alone.

Constitutionally thin individuals often eat as much as their peers and don't exercise hard. Yet their body mass index is below 18.5 — and sometimes as low as 14, which translates to 72 pounds on a five-foot frame — and they don't easily gain weight. The condition is "a real enigma," write the authors of a recent paper in the Annual Review of Nutrition. Constitutional thinness, they say, challenges "basic dogmatic knowledge about energy balance and metabolism." It is also understudied: Fewer than 50 clinical studies have looked at constitutionally thin people, compared with thousands on unwanted weight gain.

Recently, researchers have started to investigate how naturally thin bodies are different. The scientists hope to unlock metabolic insights that will help constitutionally thin people gain weight. The work may also help overweight people lose pounds, since constitutional thinness appears to be "a mirror model" of obesity, says Mélina Bailly, a coauthor of the recent review and a physiological researcher at AME2P, a metabolism research lab at the University Clermont Auvergne in France.

Genetic and metabolic factors

Individuals who eat heartily but remain inexplicably skinny were first reported in the scientific literature in 1933. Decades later, a landmark 1990 experiment demonstrated how profoundly people differ in regulating their weight.

Twelve pairs of identical twins were fed 1,000 surplus calories for six days a week. After three months of such overfeeding — equivalent to an extra Big Mac and medium fries daily — the young men had gained an average of almost 18 pounds, mostly fat, but within a large range: One gained almost 30 pounds and another fewer than 10. The latter had somehow diffused around 60 percent of the extra energy.

The study also found that the variation of weight gain was three times greater between twin pairs than within them — indicating a genetic influence on the tendency to add pounds when overfed.

Other studies confirmed that constitutionally thin people largely "resist" weight gain, particularly when eating fatty foods. Whatever pounds they do gain through overfeeding rapidly vanish once they resume normal eating.

After bouts of overfeeding, bodies generally shed weight. But as this graph illustrates, there is variability in both responses to overfeeding and in the return to a body's "normal" weight. ("Ad libitum" refers to a period in the experiment when participants eat what they want.)

This aligns with current thinking to some extent. Many researchers believe that our bodies have a preprogrammed weight "set point" or "set range" to which they try to return. That's one reason few dieters manage to keep off lost weight long-term. Their metabolism slows down, burning fewer calories and making weight regain easier, particularly once the dieter stops restricting calories. (The system displays some flexibility, explaining why many of us put on inches around our midsections over the years.)

'Skinny shaming'

As a group, lean individuals are probably as heterogeneous as overweight people. Some may stay thin because they have smaller appetites or feel full sooner. Others consume just as many calories as heavier individuals. One study found that constitutionally thin people eat 300-plus calories more per day than their metabolism needs. "They have a positive energy balance and they still resist weight gain," says Bailly, a collaborator on NUTRILEAN, a project focused on constitutional thinness, at University Clermont Auvergne in France.

Like obese people, constitutionally thin people face their social stigma. Thin men may feel too scrawny to satisfy masculine ideals. Skinny women often lament lacking curves. People might suspect they are hiding eating disorders. They get "comments from random people on the street," says Jens Lund, a postdoc in metabolic research at the Novo Nordisk Foundation Center for Basic Metabolic Research at the University of Copenhagen. "These people feel like they can't go to toilet after a family dinner … because they are afraid that people would look at them as if they're going out to puke, like having bulimia."

Weight gain coach Barnes was never technically all the way in the constitutionally thin category, but she experienced plenty of such "skinny shaming" firsthand. Family members commented on her weight but dismissed her distress. "I felt like I could never speak about it," she says. "People would be like, 'That's not a real problem,' or 'Just take some weight from me.'"

Where do the calories in constitutionally thin people go? Researchers have started eliminating possibilities.

Researchers are learning that there are large individual differences in how the body uses up calories. (Thermogenesis is the metabolic process in which calories are burned to generate heat.)

A 2021 meta-analysis offered some surprises. When Bailly and colleagues compiled data on thin people's body composition, they discovered something unexpected: Constitutionally thin individuals carry nearly normal amounts of fat throughout their bodies. "It's really unusual to have such low body weight combined with quite normal fat mass," says Bailly.

What seems to be lacking is muscle mass. Constitutionally thin people have less of it — research has found that they have muscle fibers that are on average about 20 percent smaller than those of normal-weight people. Constitutionally thin people may also have reduced bone mass.

These facts suggest that there are health costs to leanness. Though studies are lacking, Bailly suspects that as they age, especially thin women might run a higher risk of osteoporosis, a dangerous weakening of the bones. The reduced muscle mass could also make everyday tasks, like opening jars or carrying groceries, more arduous.

And it could mean fewer protein reserves during illness, says Julien Verney, a physiological researcher at Clermont Auvergne's metabolic lab and coauthor of the Annual Review of Nutrition paper.

In addition to body composition differences, researchers speculate that constitutionally thin bodies "waste" calories. For example, some studies suggest that while thin individuals exercise less, they fidget more.

They may also excrete more calories than others. While this hasn't been explored specifically for lean people, it's known that some people lose up to 10 percent of ingested calories through feces (and to a lesser extent, urine), compared to just 2 percent in others. In one study, a woman excreted 200 calories daily — equivalent to half a liter of soda.

Additional metabolic idiosyncrasies of constitutionally thin people may still await discovery. "We recently found some clues that may suggest more metabolic activity of their fat mass tissues," says Bailly. "This is really surprising." Other studies have already suggested that naturally thin people have more "brown fat" — a calorie-burning tissue that generates body heat.

To find more specific answers, Lund plans to launch an inpatient study at the University of Copenhagen. The study will use a metabolic chamber to track energy intake, expenditure and all routes of energy loss — including feces, urine and exhaled gases — in constitutionally thin people. Since 2020, Lund's team has assembled a network of Danes who self-report as naturally lean, providing a unique pool for future research.

Constitutional thinness, as the 1990 twin study showed, has a strong genetic component: Research shows that 74 percent of very lean people have relatives with similar stature. As researchers identify gene variants, they realize that many of these — with names like FTO, MC4R and FAIM2 — are also involved in processes leading to obesity. Although they don't yet understand the specifics, scientists suspect that people with constitutional thinness may have unique activity patterns in genes related to energy production.

One such gene that has drawn researchers' attention is ALK  (anaplastic lymphoma kinase). When scientists deleted this gene in mice, the animals became resistant to weight gain when fed high-fat diets — even in mouse strains genetically prone to obesity. The ALK gene seems to act in the brain, which then sends signals affecting the rate at which fat cells burn energy.

Understanding genetic mechanisms like these could lead to new treatments for both unhappily thin and unhappily obese people, says Lund. "If you can figure out what protects them from developing overweight, then whatever that mechanism is, you can then try to turn that into a drug," he says. "There are so many signaling molecules in the body that we don't even know exist." The dream is to find a breakthrough as transformative as the latest obesity medications.

While researchers hunt for biological clues, Bella Barnes navigates the complexities of weight gain on her own. After years of trial and error, she gradually gained about 40 pounds by combining strength training with careful, intentional eating. At first, if she hadn't reached her calories for the day, she'd just grab a packet of cookies — anything to get the numbers up. But she found more balance over time. "Not all calories are the same. You want to be eating whole foods," she says. And a lot of them.

Today, Barnes has coached more than a hundred women on her weight gain techniques and has a strong TikTok following; she says that she's proud of the strong body she's built.

Maybe five more pounds, she adds, "would make me at my happiest."

This article originally appeared in Knowable Magazine, a nonprofit publication dedicated to making scientific knowledge accessible to all. Sign up for Knowable Magazine’s newsletter.

Although Kennedy agreed that Operation Warp Speed, President Donald Trump's signature initiative to produce COVID-19 vaccines in nine months, was a tremendous achievement, he also maintained that COVID-19 vaccines cause widespread and serious harm, including death, particularly in young people — a claim for which there is no evidence.

Some especially pointed questions came from Republican Sen. Bill Cassidy of Louisiana, a physician who provided the final vote needed for Kennedy's confirmation in February 2025 after Kennedy promised him that he would not change the Centers for Disease Control and Prevention's process for recommending vaccines. Cassidy pointed out that with the limitations and confusion caused by the CDC's new rules around COVID-19 vaccines, "I would say effectively we are denying people vaccines." To which Kennedy replied, "Well, you're wrong."

At the hearing, Kennedy stood by his decision to cut US$500 million in HHS funding for 22 research contracts on mRNA vaccine technology. HHS has said it will instead pour these funds into research on a traditional approach to designing vaccines that was first used more than 200 years ago. With such vaccines, called whole-virus vaccines, a person's immune system is presented with the whole virus, often in weakened or inactivated form. This switcheroo has puzzled many scientists.

A few days before the hearing, on Sept. 1, Trump demanded that pharmaceutical companies prove that COVID-19 mRNA vaccines work, saying that the CDC was "being ripped apart over this question." It was his first public acknowledgment of the chaos roiling the CDC amid the firing of its director, Susan Monarez, and subsequent resignations of four high-level agency officials.

Meanwhile, public health experts and HHS staffers are calling for Kennedy to be fired, and several senators at the hearing echoed that call.

As a vaccinologist who has studied and developed vaccines for over 35 years, I see that the science behind mRNA vaccine technology is being widely misstated. This incorrect information is shaping long-term health policy in the U.S. — which makes it urgent to correct the record.

Are mRNA vaccines less safe than whole-virus vaccines?

HHS defended its cancellation of mRNA vaccine research based, in part, on a nonpeer-reviewed compilation of selected publications called the COVID-19 mRNA "vaccine" harms research collection. This document lists about 750 articles claimed to describe harms caused by mRNA vaccines against COVID-19. However, the vast majority of these articles aren't about vaccines but about the harms of getting infected with SARS-CoV-2, the virus that causes COVID-19. And notably absent from it is the huge body of data showing mRNA vaccines actually prevent these harms.

For example, the document being used to justify RFK Jr.'s claims about mRNA vaccines highlights 375 studies reporting that the virus's spike protein alone, which is produced when the virus replicates, can cause excessive inflammation and tissue damage. This is true. But the document marshals this evidence to support the claim that mRNA vaccines, which are designed to produce spike proteins, cause the same harm — which is not accurate.

While viral replication results in uncontrolled production of a large amounts of the protein, the way it's produced by the mRNA vaccine is very different. The vaccine produces a small, controlled amount of spike protein inside a few cells — just enough to induce an immune response without causing damage. And by blocking the virus's replication, it reduces the amount of spike protein in circulation, actually having the opposite effect.

What about side effects like myocarditis?

Early reports flagged a type of heart swelling called myocarditis as a rare side effect of the mRNA vaccine, particularly for young men ages 18 to 25 after a booster dose. A 2024 review identified about 20 cases out of 1 million people who received the vaccine. However, that same study found that unvaccinated people had an elevenfold higher risk of getting myocarditis after a COVID-19 infection than vaccinated people.

What's more, another 2024 study showed that people who developed myocarditis after vaccination had fewer complications than those who developed the condition after getting infected with COVID-19.

Do mRNA vaccines make the SARS-CoV-2 virus resistant?

Another claim from the compilation of supposed mRNA vaccine harms that was cited as a reason for cutting funding for mRNA technology is that mRNA vaccines cause mutations in the SARS-CoV-2 virus that make them resistant or less susceptible to the vaccine.

When a virus replicates in its host, it produces millions of copies of its genetic material. Mutations are copying errors that occur naturally during the replication process. These acquired mutations produce new variants, which is why both the COVID-19 mRNA and the whole-virus flu vaccine get updated annually — to keep up with natural changes in the virus.

Slowing down viral replication decreases the rate at which a virus can acquire new mutations. Since both mRNA and whole-virus vaccines stop or slow the virus from replicating, both types of vaccines help reduce the emergence of resistant viruses.

Viruses can mutate to escape from antibodies, but the mRNA vaccines are not causing the emergence of more virulent strains, likely for at least two reasons. First, mRNA vaccines induce immune responses that can attack the virus at multiple spots, so it would have to come up with many mutations at once to escape the vaccine's defenses. Second, even if the virus could acquire all these mutations, they would likely weaken it, making it unable to cause or even transmit disease.

mRNA vaccines versus new SARS-CoV-2 variants

Kennedy, in announcing cuts to mRNA vaccine research on Aug. 5, 2025, claimed that mRNA vaccines don't work against respiratory viruses and that HHS was moving toward "safer, broader vaccine platforms that remain effective even as viruses mutate."

Both whole-virus vaccines and mRNA vaccines protected against COVID-19 and prevented hospitalization and death for millions of people worldwide between 2020 and 2024, but there's clear evidence that the mRNA-based vaccines provided significantly better protection than whole-virus vaccines. And for COVID-19, mRNA vaccines are more effective against new variants, which emerge as viruses mutate, than whole-virus vaccines.

The COVID-19 mRNA vaccines started with exceptionally high efficacy, exceeding 94%. When the SARS-CoV-2 delta and omicron variants emerged in the spring and fall of 2021, mRNA vaccines became less effective in preventing infections. However, they remained highly effective in preventing severe illness, whereas in unvaccinated people the rates of severe illness and hospitalization remained high.

This is because mRNA vaccines induce the immune system to make both antibodies and specialized immune cells called T cells. These elements can recognize multiple parts of the virus, including ones that don't change, enabling significant protection against new variants.

What's more, the mRNA vaccines have a superpower that no other type of vaccine can currently match: They can be quickly updated and manufactured within two to three months. To develop a whole-virus vaccine, researchers must first spend months isolating and propagating the virus. Conversely, making an mRNA vaccine requires just sequencing the virus's genetic code — a process that today takes just hours.

If a new pandemic began today, mRNA vaccines are currently the only type of vaccine that could be developed quickly enough to disrupt its spread.

The future of mRNA vaccine technologies

Thirty years ago, when scientists first started developing mRNA vaccine technology, they recognized its potential to overcome major limitations of whole-virus vaccines — namely, slow production time and more limited ability to protect from new viral variants. Today, mRNA vaccines are also being developed to prevent or treat diseases including HIV and cancer, as well as autoimmune and genetic diseases.

Of course, this technology can be further improved. New mRNA vaccine technologies are aimed, among other things, at making mRNA vaccines easier to store to allow for faster distribution and reduce their short-term side effects, eliminate the rare risk of myocarditis and more quickly block a respiratory infection.

The National Institutes of Health is funneling money away from new mRNA technologies toward a single project developing universal vaccines based on traditional whole-virus vaccine technology. Universal vaccines are urgently needed to provide broader protection against ever-changing respiratory viruses, such as influenza, that are major pandemic threats.

A 2022 study in mice and ferrets showed that a universal flu vaccine NIH plans to support has promise. However, multiple studies of potential universal flu vaccines based on mRNA technology show even more potential. Such vaccines could induce broader immunity than whole-virus vaccines by eliciting antibody and T-cell responses that target an even wider range of flu viruses.

It's hard to square those benefits with the fact that HHS and NIH have named the planned new universal vaccine platform "Generation Gold Standard," insisting that it represents a new standard in science and transparency. The effort seems more akin to eliminating all e-bike technology and telling everyone who seeks one to get by with a single brand of a 10-speed bike: Getting to the intended destination may still be possible, but it will be slower and harder.

And in the case of abandoning mRNA vaccine research, it may lead to lives needlessly lost, whether due to potential medicines untapped or to pandemic unpreparedness.

This article was updated to include details from Kennedy's Sept. 4, 2025, hearing.

This edited article is republished from The Conversation under a Creative Commons license. Read the original article.

That's according to a new landmark study, which combined the predictions of 25 climate models to arrive at an "optimistic" prediction (under a moderate emissions scenario) that the current will begin to shut down due to climate change sometime in the 2060s. Given the current's vital role in regulating global climates, scientists have described the study as a "serious climate wake-up call."

Elsewhere, the signs of our warming world can be seen in the invasion of Antarctic icebergs around the South Atlantic Ocean's South Georgia Island. There, the former record-holder for the largest iceberg in the world, A23a, is undergoing a dramatic breakup. Meanwhile, deep beneath the Pacific Ocean, a team of scientists has discovered a giant hydrothermal system that could hold clues to the origins of life on Earth.

Mouse brain scans rewrite the textbook

Map of 600,000 brain cells rewrites the textbook on how the brain makes decisions

It's not often that a single piece of research comes along with the potential to rewrite everything that came before. Yet a massive collaboration of neuroscientists may have done just that with two new studies that mapped more than 600,000 individual mouse brain cells — or 95% of the rodents' brains.

The scientists hope the mammoth effort will help them study what parts of the mammalian brain are responsible for making decisions. In the past, scientists assumed that brain activity moves in a linear path, from visual recognition of a stimulus to regions responsible for abstract thinking, mixed with sprinklings from the memory regions to draw from experience.

But the new research found that significantly more of the mice's brains participated in this process, with decisions beginning to coalesce far earlier than expected. So far, the findings are only correlational, meaning the scientists still don't know whether all the regions are contributing, but they plan to attack this question as the next step of their work.

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The trial results, published Thursday (Sept. 4) in JAMA, include data from 194 people with moderate to severe anxiety across the U.S. The study compared these participants' responses to different doses of LSD against a placebo treatment. It found that the drug alleviated symptoms in many patients for at least three months after just one exposure.

That said, participants who were given low doses of LSD — either 25 or 50 micrograms — did not see a significant change in their symptoms. The effect kicked in only at higher doses — either 100 or 200 micrograms — and those given 100-microgram doses had the best results.

In fact, 12 weeks out from treatment, about 47% of the people who were given 100 micrograms were in remission, based on a standardized anxiety rating scale. And about 65% of the people in that group saw their scores on the scale fall by at least half. By comparison, only about 20% of the placebo group was in remission at the 12-week mark and about 30% saw their scores halved.

"This work has the potential to make significant contributions to the emerging field of psychedelic drug research," Dr. Claudio Soares, a professor of psychiatry at the Queen's University School of Medicine in Ontario, wrote in a commentary about the trial. It's the first study to examine how different doses of LSD compare with a placebo for relieving anxiety. In addition, the trial didn't explicitly incorporate psychotherapy into the treatment, meaning it could help pin down whether LSD in and of itself has an anti-anxiety effect, he added.

"Furthermore, the study highlighted an early response to treatment and positive effects on comorbid depressive symptoms, both of which are promising findings that should guide future trials," Soares said.

Related: 1 psychedelic psilocybin dose eases depression for years, study reveals

While there are approved anti-anxiety drugs, not all patients respond to them, the trial runners noted in their report. Estimates suggest about 50% of patients do not have an adequate response to first-line anxiety treatments, such as benzodiazepines or serotonin selective reuptake inhibitors (SSRIs, which are also used for depression).

As such, there's still a need for more effective, well-tolerated anti-anxiety medicines, the trial runners argue.

Enter LSD. The psychedelic is thought to trigger its mind-altering effects — such as visual hallucinations and a feeling of being high — in part by enabling communication between brain cells that don't normally interact. It's thought that this action might trigger a period of enhanced plasticity in the brain, during which a person with anxiety could break out of the harmful thought patterns that characterize the condition. But this mechanism is not fully understood and is still being studied.

Trials that have combined LSD with psychotherapy hinted that the drug can have a positive and sustained effect in treating anxiety. But because these trials were testing two interventions — LSD plus therapy — it's hard to know what LSD was contributing on its own.

The new trial aimed to investigate that question by including people who were not undergoing psychotherapy. In all, 18% of the participants were receiving external psychotherapy when they entered the study and continued receiving therapy during the study, the report noted.

At baseline, the 194 participants scored an average of 30 on an anxiety scale from 0 to 56, where the threshold for "severe" anxiety is 24. A score of 7 or less indicates remission. Patients given the 100-microgram dose saw, on average, a 21-point drop in their scores.

"A treatment effect emerged 1 day after the dosing day and persisted through week 12," the report authors noted.

The vast majority of side effects tied to the treatment were expected and resolved once the dosing of the drug concluded. These effects included visual perception changes, nausea, headache and euphoric mood. Notably, side effects were reported across all the study groups, including the placebo group, but occurred at the highest rates in the high-dose groups. For instance, more than 90% of the 100-microgram group reported hallucinations, as did 100% of the 200-microgram group.

Two people reported "feeling intoxicated" in the 50- and 100-microgram groups, respectively, but felt normal by the end of the dosing session.

Although the side effects were generally mild to moderate in severity, they did prompt a handful of people to drop out of the trial, so the LSD treatment may not be tolerable to all patients.

The trial does have some limitations, including the short follow-up time of only three months and the inclusion of some patients who still underwent therapy during the trial, Soares said. But in all, the trial provides crucial data that could help "further inform regulatory pathways for the use of psychedelic drugs as stand-alone treatments," he said.

Future research will be needed to evaluate how well the effects of the drug last over longer time frames, particularly after a single dose, he concluded.

This article is for informational purposes only and is not meant to offer medical advice.

These tiny microrobots are bull sperm cells coated in magnetic nanoparticles. Researchers haven't tested them inside a real organism, whether cow or human, yet, but they demonstrated that they can control the sperm bots inside a life-sized anatomical model of the female human reproductive system and track their progress with X-rays.

The sperm bots, described Tuesday (Sep. 2) in the journal npj Robotics, could one day be used to improve reproductive medicine, drug delivery and infertility diagnosis, the researchers said in a statement.

"We're turning nature's own cell delivery systems into programmable microrobots," study lead author Islam Khalil, an associate professor in the robotics and mechatronics research group at the University of Twente in the Netherlands, said in the statement.

Related: 'I would never let a robot incubate my child': Poll on 'pregnancy robots' divides Live Science readers

Microbots are microscopic devices that scientists are developing so that they can be deployed inside the body for highly precise, targeted medical treatments. For example, in 2022, researchers used an army of swimming microbots to eradicate a deadly pneumonia infection in mice.

When it comes to reproductive health, scientists say that microbots have the potential to deliver drugs directly to the uterus, fallopian tubes and other difficult-to-access parts of the female reproductive system. Such a targeted drug delivery system could improve treatments for ailments such as uterine cancer and fibroids, the study authors propose.

Khalil was part of a team that unveiled biohybrid magnetic sperm microrobots in 2020. In the new study, researchers found that increasing the concentration of iron oxide nanoparticles on the bots' outer coating improved the team's ability to control and detect the little machines, while still ensuring the nanoparticles weren't harmful to the uterus. At least, the bots weren't toxic to human uterine cells after 72 hours of exposure.

The team tested their little sperm bots in a 3D printed model of a portion of the female reproductive tract, using an external magnetic field to pilot them from the ersatz cervix, through the uterine cavity, and toward the fallopian tubes, where fertilization most often occurs. They found that the bots could be tracked throughout the journey in real time using X-rays, something that isn't possible with natural sperm.

"Until now, visualising sperm inside the body was nearly impossible," Khalil said.

A lack of real-time sperm tracking has hampered scientists' understanding of reproductive health and fertility treatments, the authors say. The researchers noted that having a noninvasive way of tracking sperm could help them better understand sperm transport systems and male infertility, for instance.

Our question is, how much do you know about some of the greatest athletic achievements of all time? This quiz will help you find out whether your knowledge of sports records is up to scratch.

Below, you will find 10 questions related to different aspects of human strength and endurance. Let's see if you can name the fastest 100-meter dash, the longest breath hold underwater or the highest jump ever recorded. We know it is a lot of numbers and stats to go through but hints are available if you click the yellow button!

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The device, which has so far been tested in rabbits, would be particularly useful for fixing irregularly shaped fractures during surgery, the researchers say.

"To my knowledge, there are virtually no previous examples of applying the technology directly as a bone substitute," study co-author Jung Seung Lee, a biomedical engineer at Sungkyunkwan University in South Korea, told Live Science in an email. "This makes the approach quite unique and sets it apart from conventional methods."

Typically, large fractures or other defects in bones require bone grafting and the use of a metal fastener, such as a pin or plate, to support the broken bone as it heals. But because the shape of these implants is not specific to a given patient's fracture, this can result in poor alignment and compromised stability of the bone.

Previous studies have shown that 3D printing bespoke bone grafts for individual patients can be done, but these required considerable time and effort to make, preventing them from being used on the fly during surgery.

Now, in a study published Friday (Sept. 5) in the journal Device, Lee and colleagues detailed their new method of 3D printing a bone substitute directly onto a fracture using a glue gun. In the research, they successfully tested the technology on rabbits with leg fractures.

Related: Injectable goo could fix joints without surgery, early study suggests

Basic 3D printing commonly uses a flexible, plastic thread, which is heated and then formed into the desired shape. But Lee and colleagues created a filament composed of two materials: polycaprolactone (PCL), which has been used in previous studies to create biodegradable bone scaffolds, and hydroxyapatite (HA), a mineral form of calcium important for bone structure. They also incorporated two antibiotics into the filament to help prevent infection; these drugs diffuse slowly out of the filament over several weeks.

Using a glue gun modified to extrude the calcium-based filament at a low temperature, the researchers created small shapes that cooled to body temperature within 40 seconds. They were then able to print 3D bone grafts directly onto fractures and defects during surgeries on the lab rabbits.

"This highlights a significant advantage in terms of reducing operative time and improving procedural efficiency under real surgical conditions," Lee said in a statement.

The researchers tested their 3D-printed bone grafts on New Zealand white rabbits (Oryctolagus cuniculus). They braced the fractures with metal plates and screws, and then filled the rabbits' bone defects with either their special bone-like filament or with traditional bone cement and followed the rabbits' progress over 12 weeks.

The rabbits with the new fracture treatment had better outcomes, including better bone tissue formation and denser bone growth over the three months, compared to the rabbits given traditional treatment. By the end of the study period, the experimental bone material had degraded by about 10%, they noted.

"We have confirmed the therapeutic potential of this technology using a rabbit model," Lee told Live Science, noting that further studies in larger animal models are needed before the technology can be used on humans. Nonetheless, Lee said, "we believe this approach has the potential to be used more widely in future trauma surgery."

Gout is a type of arthritis that causes sudden, severe pain and swelling in the joints. It happens when there is too much uric acid in the blood, which can form sharp crystals in the joints, triggering painful inflammation. The painful attacks can come on quickly and may last for days or weeks.

While there are several drugs that have been developed to manage elevated uric acid levels, many have either seen limited success or significant drawbacks, including side effects like harmful immune responses.

But in a study published July 18 in the journal Scientific Reports, researchers developed a potential new method of reducing uric acid: They restored the function of a gene humans lost millions of years ago with the help of CRISPR gene editing.

"Human cells still know what to do with that protein" made by the lost gene, study co-author Eric Gaucher, a geneticist at Georgia State University, told Live Science. A postdoctoral scholar in Gaucher's lab, Lais de Lima Balico, was the second co-author on the study.

"Medications used to treat gout … are very effective when taken consistently, but adherence rates to these medications are among the lowest of any chronic disease," Dr. Chen Xie, a rheumatologist at UCLA who was not involved in the study, told Live Science in an email. "A gene editing-based treatment to lower uric acid could be a medication-free, curative therapy that could bypass a lot of practical treatment issues we currently face."

So far, the researchers have explored the idea only in lab studies with human cells, but they say their results suggest that a gene therapy could someday be a viable option for patients with gout.

While gout is a fairly common condition that affects 1 in 25 people worldwide, it is very rare in mammals other than primates. This is because other animals have an active gene for an enzyme called uricase, which breaks down uric acid in the blood and thereby prevents the formation of crystals. However, due to a number of mutations picked up over our evolutionary history, the uricase enzyme in humans cannot process uric acid. Some researchers believe this happened because increased levels of uric acid can also turn fruit sugar into fat, helping primates survive winters and grow bigger brains.

Related: US baby receives first-ever customized CRISPR treatment for genetic disease

Researchers had previously identified which ancient genes may have been responsible for producing uricase by inferring ancestral genes. This means figuring out what the genes of ancient organisms looked like by studying the DNA of living species today. Scientists compare the genes of different animals or people, use computer programs to build family trees, and then make educated guesses about what the original, ancient gene sequences were. Once they have a good idea of what those old genes looked like, they can recreate and "resurrect" the ancient proteins that the genes encode in the lab and possibly open the door to new therapies.

In the new study, researchers used CRISPR gene editing to insert the ancient uricase gene into the genomes of human liver spheroids. Spheroids are 3D blobs of lab-grown tissues that mimic complex, full-size organs found in the body. The insertion of the ancient gene resulted in a drop in uric acid, as well as a reduction in fat buildup related to fruit sugars.

There are existing gout therapies that use uricase to manage high levels of uric acid; for example, the treatment Krystexxa involves injections of uricase proteins made using a combination of pig and baboon gene sequences. However, these protein-based therapeutics often elicit strong immune responses and require clinical monitoring due to the risk of anaphylactic shock.

By contrast, a gene therapy that restores the original, ancient human gene sequence could enable the body's own cells to produce uricase. In theory, the immune reactions could be minimized because much of the uricase protein sequence is already recognized and accepted by the human body.

But the researchers have a long way to go before such a gene therapy could be used in human patients. For next steps, they are transitioning from liver spheroids to lab mice, and they're using nanoparticle delivery systems that introduce CRISPR gene-editing components directly into liver cells.

Such a gene therapy has the potential to transform gout treatment by providing a long-lasting and possibly safer alternative to current therapies, the researchers say. Gene-editing therapies like this, however, are still in early stages of development.

The researchers hope that this approach — of taking and adapting ancient genes for modern therapies — could be more broadly applied in the future.

"My ultimate goal is to be able to wed molecular evolution and clinical medicine," Gaucher said. "Ideally we can use ancient proteins or ancient enzymes to develop therapeutics to help modern society."

Editor's note: This story was updated on Sept. 5, 2025, to add a comment from Dr. Chen Xie.

This article is for informational purposes only and is not meant to offer medical advice.

The project, involving a dozen labs and data from over 600,000 individual mouse brain cells, covered areas representing over 95% of the brain. Findings from the research, published in two papers in the journal Nature, suggest that decision-making involves far more of the brain than previously thought.

The mammoth project was led by the International Brain Laboratory (IBL), a collaboration of experimental and theoretical neuroscientists from across Europe and the U.S. These scientists were united by a familiar, nagging feeling.

"We had a problem with the way science was done," said Matteo Carandini, a neuroscientist at University College London and a core member of the IBL.

In previous studies of the brain, many separate labs set out to answer big questions about the organ, exploring how brain activity relates to behavior, for instance. However, each lab studied this question in different mice's brains, and performed slightly different behavioral tasks with each set of rodents. Once you added in uncertainties around how each research group defined distinct regions within the brain, these inconsistencies muddied the results.

"We wouldn't know whether we actually agree or disagree, because so many things were different," Carandini told Live Science.

Related: Most detailed human brain map ever contains 3,300 cell types

So the IBL came together to design a single, robust, standardized experiment on a scale that no individual lab could tackle alone. They then paired this megatest with precision brain measuring tools and preset analysis methods to make the results as reproducible as possible. The aim of the experiment would be to overcome an enduring obstacle in the field.

"One of the longest-standing challenges in neuroscience is to decipher how variation in neural systems — both structural and functional — maps onto variation in behavior," Federico Turkheimer, a neuroscientist at King's College London who was not involved in the study, said in a statement to the U.K. Science Media Centre.

This project ultimately included 139 mice, spread across 12 labs around the world, that were implanted with brain-recording devices called Neuropixels probes. The probes can record up to 1,000 individual neurons simultaneously. The researchers tested the mice with a simple behavioral task that each of the dozen labs could reliably replicate: Researchers placed mice in front of a screen, and a black-and-white striped marker would flash either on the right or left. If the mice moved a small wheel in the same direction as the flash, they received a reward.

Based on what you'd read in a neuroscience textbook, said Carandini, you'd expect the brain activity that occurred during the experiment to follow a linear path. First, cells in the visual cortex that recognize images would fire up, followed by neurons in a different part of the brain, such as the prefrontal cortex, known to be involved in abstract decisions. This information might then be combined with additional activity that represented the mouse's prior experiences — in other words, memories — before being sent to motor regions of the brain that control muscle responses.

The researchers' findings supported some of this chain reaction; the visual cortex was the first thing to activate, for example. Yet other findings clashed with the team's expectations.

"We found decision signals and signals related to the prior information in way more brain regions than we might have thought," Carandini said. Taken together, the activity across nearly all of the brain regions studied could be used to deduce whether or not the mouse had received a reward.

In some of the experimental trials, the researchers made the on-screen marker incredibly faint, so the mice essentially had to guess which way to move the wheel. The second Nature paper focused on how the mice used prior expectations — based on where the marker had been in previous tests — to inform their guess. The brain activity that flashed up when the mice guessed in these tasks was also far more widely distributed in the brain than the team anticipated it would be.

The IBL modeled its approach to understanding the brain on similar initiatives, such as the particle physics experiments conducted at CERN or the Human Genome Project's work to understand our DNA. To describe the project's impact, Carandini reaches for yet another field: astronomy.

He noted that the earliest astronomers could look up at the night sky and see every star, but in very poor detail. With the advent of the telescope, individual celestial bodies could be explored. Previous work in neuroscience, he said, was "as if somebody had pointed a telescope only to one galaxy, and then different astronomers had pointed their telescopes at different galaxies, and said, 'My galaxy does this!' or 'No, my galaxy does that!" The new project, he explained, was like being able to view all the features of the night sky at once and up close.

Such work has only been possible with recent technological advances and improved collaboration across labs, but Carandini hopes that it can now be used to address other big questions about the brain. The current paper's findings are only correlational, so it is currently not possible to say whether the observed brain activity directly causes a decision to be made or is only associated with the process.

"I think that's the next frontier," he said, "is to add causality to the study."

The mighty Molekule Air Pro is now 21% off, bringing its price down by a solid $215, while its smaller and less powerful sibling Air Mini+ is 17% off, saving you a neat $60. We spotted the same deal at Amazon and a couple of other retailers just yesterday, but it has already sold out. Do not dwell too long on this offer from Macy's, as we do not expect it to last long, either.

During our Molekule Air Pro review, we were particularly impressed by its ability to remove smoke. Every air purifier we test is subjected to smoke tests, where we burn 10 matches, then run the machine for 15 and 30 minutes on its auto setting. After just 15 minutes, the Molekule Air Pro removed a whopping 99.9% airborne particles. After 30 minutes, the air quality was better than when we started. Indeed, it is one of the most powerful appliances we have ever tested, which is why we gave it a strong 4/5 rating and a spot in our guide to the best air purifiers.

Robust air quality monitoring is another aspect in which Molekule tends to outshine the competitors. While most air purifiers use simple color-coded air-quality indicators, the Air Pro and Air Mini will tell you exactly how much pollution is in the air, breaking it down into volatile organic compounds (VOCs), carbon dioxide (CO2), relative humidity and three separate categories of particulate matter (PM1.0, PM2.5, and PM10). The Molekule app will then track the air quality over time, allowing you to identify any significant spikes and drops in the levels of specific air pollutants.

The Molekule Air Pro is both a real powerhouse of an air purifier and an ultra-robust air quality sensor — and right now, you can knock $215 off its original price.

Key features: PECO-HEPA Tri-Power Filter, FDA clearance, 2 auto modes, 6 fan speeds, app and voice control, comprehensive air quality readings

Product launched: September 2020

Price history: For the better part of this year, the price of Molekule Air Pro fluctuated between $899.99 and $1,014.99. The price of the Air Mini+ model, on the other hand, sat mostly at $359.99, occasionally dropping to as low as $299.99. Today's offer from Macy's brings their prices down to $799.44 and $299.99, respectively.

Price comparison: Molekule: $1,014.99 & $339.99| Walmart: $849.99 & $359.99 | Target: $1,014.99 & $359.99

Reviews consensus: The Molekule Air Pro universally impressed the reviewers with its exceptional air-cleaning performance, ultra-sleek design and handy smart features. Many testers also praised its robust air quality monitoring, portability and ease of use. However, none of the reviewers gave this air purifier a full five stars, citing its sky-high price, expensive filter replacements and noisiness at high fan speeds.

Homes & Gardens: ★★★★ | Live Science: ★★★★ | Tom's Guide ★★★★ | TechRadar: ★★★★

Featured in guides: Best air purifiers

✅ Buy it if: You want a stylish and ultra-powerful air purifier that offers an array of smart features and detailed air quality readings.

❌ Don't buy it if: You want something that is whisper-quiet and less 'techy'.

Check out our other guides to the best air purifiers, air purifiers for allergies, the best telescopes, microscopes for students, binoculars, rowing machines, electric toothbrushes and more.

The symptoms: The patient had a prior diagnosis of osteoarthritis of the knee — a degenerative joint condition that causes pain and stiffness. She had previously sought medical attention, and was treated with painkillers and nonsteroidal anti-inflammatory drugs for the condition. She had also previously received steroid injections directly into her knees, but her pain remained.

She then started to get bad stomach pain from the medications, so she had stopped them altogether.

What happened next: The woman decided to seek alternative treatments to ease her joint pain and began having weekly acupuncture. She increased the frequency to multiple times a week when the pain was particularly bad.

She later went to the hospital because her knees were very sore. X-rays of her left knee revealed that the shinbone in the inner part of the joint had thickened and hardened. There were also bony growths, called spurs, on the inner portions of the shinbone and thigh bone by the knee joint.

The doctors also saw hundreds of flecks on the X-ray around the knee joint, which turned out to be tiny gold threads.

The diagnosis: The doctors learned that the threads had been inserted as part of the woman's acupuncture treatments. These short, sterile golden threads were purposefully left in the tissue to provide continued stimulation.

The treatment: The doctors did not report whether the gold threads were removed from the patient, but in previous cases, the threads have been left in place.

Leaving the threads in place is not risk-free, as it has led to cysts forming in past cases.

What makes the case unique: Gold-thread acupuncture is commonly used to treat both osteoarthritis and rheumatoid arthritis in Asia, the doctors wrote in a report of her case. However, there is no evidence the practice works, and some cases suggest it can indirectly worsen arthritis by keeping people from getting appropriate, timely treatment.

For instance, in another case, a 58-year-old South Korean woman had received gold-thread acupuncture in an attempt to ease rheumatoid arthritis pain in her wrists. The patient's condition had gotten particularly severe by the time she sought medical attention, and the doctors in that case believed her disease had progressed so far because she had not taken anti-rheumatoid medications early enough and had instead relied on the alternative medicine approach.

Also, the threads can migrate within the body, and fragments can damage neighboring tissue. For example, gold threads inserted into a 75-year-old South Korean woman's back migrated to her lower right leg over a 10-year period, causing cellulitis — a deep skin infection.

In their report of the knee case, the doctors noted that gold threads inserted during acupuncture can make it challenging to read X-rays.

Others have warned that these embedded gold strands stop people from being able to have MRIs because of the risk of the metal moving and damaging an artery.

As such, doctors have noted that health care providers should be aware of the potential risk factors associated with gold-thread acupuncture. However, the fact that they are easy to identify on X-rays ensures that their location can be tracked over time if necessary.

This article is for informational purposes only and is not meant to offer medical advice.

But these people hadn't caught any known virus.

Instead, ancient genes originally from viruses, and still lurking within these patients' chromosomes, had awakened and started churning out viral proteins.

Our genomes are littered with scraps of long-lost viruses, the descendants of viral infections often from millions of years ago. Most of these once-foreign DNA bits are a type called retrotransposons; they make up more than 40 percent of the human genome.

Our genomes are riddled with DNA from ancient viral infections known as jumping genes. The majority of these are retrotransposons, which copy themselves via RNA intermediates; a smaller portion are cut-and-paste DNA transposons.

Many retrotransposons seem to be harmless, most of the time. But Douville and others are pursuing the possibility that some reawakened retrotransposons may do serious damage: They can degrade nerve cells and fire up inflammation and may underlie some instances of Alzheimer's disease and ALS (amyotrophic lateral sclerosis, or Lou Gehrig's disease).

The theory linking retrotransposons to neurodegenerative diseases — conditions in which nerve cells decline or die — is still developing; even its proponents, while optimistic, are cautious. "It's not yet the consensus view," says Josh Dubnau, a neurobiologist at the Renaissance School of Medicine at Stony Brook University in New York. And retrotransposons can't explain all cases of neurodegeneration.

Related: Best-ever map of the human genome sheds light on 'jumping genes,' 'junk DNA' and more

Yet evidence is building that they may underlie some cases. Now, after more than a decade of studying this possibility in human brain tissue, fruit flies and mice, researchers are putting their ideas to the ultimate test: clinical trials in people with ALS, Alzheimer's and related conditions. These trials, which borrow antiretroviral medications from the HIV pharmacopeia, have yielded preliminary but promising results.

Meanwhile, scientists are still exploring how a viral reawakening becomes full-blown disease, a process that may be marked by what Dubnau and others call a "retrotransposon storm."

Genes that jump

A retrotransposon is a kind of "jumping gene." These pieces of DNA can (or once could) move around in the genome by either copying or removing themselves from one spot and then pasting themselves into a new spot. Retrotransposons are copy-and-pasters.

Many retrotransposons are old companions: Some predate the evolution of Homo sapiens or even the split between plants and animals, Dubnau says. Their predecessors may have alternated between riding along stitched into a host chromosome and existing outside of it, he suggests.

Some retrotransposons, after all that time, retain their ability to hop around human DNA. To do so, they copy themselves with the enzyme reverse transcriptase, which is also used by some viruses like HIV to copy RNA sequences into DNA. Once they're copied, the remnant viruses can pop into new locations on chromosomes.

If it's terrifying to think of a genome littered with retroviral genes, some capable of bouncing around the genome, don't fret, says Douville, now at the University of Manitoba in Winnipeg. Remarkably, some retrotransposons have taken on helpful jobs, assisting the body with tasks like maintaining stem cells and development of the embryo and nervous system.

And many retrotransposons are dormant or broken, and the cell has means to keep them (mostly) quiet. One technique is to stash them in DNA regions that are wound up so tight that the molecular machines needed to copy genes can't get near them.

In essence, the cell shoves them into a closet and slams the door shut.

But evidence is building that as people age, that closet door can creak open, letting retrotransposons spill out. Exactly what they do then isn't certain. Some scientists think it's not so much that they are jumping around and mutating DNA, but that their viralesque RNAs and proteins can screw up normal cellular activities.

"I think what's actually driving toxicity when transposons are activated is they're making all these factors that look like a virus to the cell," says Bess Frost, a neurobiologist at Brown University in Providence, Rhode Island. The cell reacts, quite reasonably, with defensive inflammation, which is commonly associated with neurodegeneration.

Retrotransposons also seem to team up with rogue proteins classically linked to neurodegeneration, damaging or killing nerve cells, and perhaps even setting off the disease in the first place.

Making the ALS connection

Scientists long suspected a link between viruses and ALS, which causes degeneration of the motor neurons that control movement. But the connection, when it was finally found, wasn't quite what anyone predicted.

In the early 2000s, scientists reported that some people with ALS had the viral enzyme reverse transcriptase in their blood and, more rarely, spinal fluid. Some had as much reverse transcriptase as a person with an HIV infection.

But at the time, says Dubnau, "Nobody could find a virus."

Finally, Douville and colleagues discovered evidence for one of those leftover viruses, a kind of retrotransposon called HERV-K, in the brains of some people who had died of ALS. From there, scientists began to build a case linking jumping genes to ALS in people, lab animals and cells in dishes. A team reported in 2017 that numerous jumping genes had been activated in the brains of certain people with ALS.

Douville's colleagues also documented damage inflicted by HERV-K: When they put a gene from the retrotransposon into mice, the animals' nerve cell projections shriveled and they exhibited ALS-like symptoms.

As the scientists zeroed in on what might be waking up HERV-K, a familiar protein turned up. Called TDP-43, it had already been linked to ALS. But even before that, it was found to be involved in cells' responses to the retrovirus HIV.

Scientists discovered in the 1990s that TDP-43 works in the cell's nucleus, where it hinders activation of HIV genes. It also regulates human genes there. But in the neurons of people with ALS or a related condition, frontotemporal dementia (FTD), TDP-43 departs the nucleus and goes on to form abnormal clumps in the cytoplasm. The globs have been associated with a number of neurodegenerative conditions and can spread from cell to cell. And when TDP-43 vacates the nucleus, it also creates a gap in gene regulation, throwing off the activity levels of many genes.

TDP-43 gone bad is sufficient to cause neurodegeneration, but studies indicate its desertion of its nuclear role can also wake up retrotransposons. When TDP-43 leaves the nucleus, tightly coiled DNA next to certain retrotransposons starts to loosen up and unravel, a study of cells from the brains of people who died of ALS or FTD revealed. And researchers saw that in cultured cells, this loss of TDP-43 freed certain retrotransposons from their restraints. The closet door was now ajar, in other words, allowing the retrotransposons to jump out and around.

Meanwhile, Dubnau and collaborators, were looking at data on TDP-43 and the genes it controls in rats, mice and people. They found that TDP-43 can naturally stick to the RNAs of a variety of jumping genes, suggesting a way that normal TPD-43 might continue to corral them, even if they've managed to get copied into RNA. That interaction was altered in people with FTD and in rodents with abnormally high or low amounts of TDP-43 — very much as if TDP-43 was unable to control the jumping genes anymore.

The Dubnau group also turned to fruit flies. Both old age and the human TDP-43 gene caused retrotransposons in the fly brain to sneak out of the chromosomal closet, inducing brain cells to kill their neighbors and prompting neurodegeneration, the group reported in a series of papers from 2013 to 2023. Moreover, activation of certain retrotransposons also caused TDP-43 to clump together outside of the nucleus, creating a vicious cycle whereby TDP-43 and the retrotransposons reinforce each other's abnormal behaviors. Past a certain point, says Dubnau, "It just takes off."

Based on the sum of all these findings, Dubnau suggests a possible way that ALS could develop: Normally, TDP-43 in the nucleus helps to repress retrotransposons. But if aging or some other disturbance causes TDP-43 to decamp, those once-silenced retrotransposons spring to life, producing virus-like RNAs and proteins. While the retrotransposons might induce disease on their own, by jumping into new DNA locations or spurring inflammation, they also act on TDP-43. They force more TDP-43 to leave the nucleus and clump in the cytoplasm, causing further neurodegeneration that spreads to neighboring cells.

This isn't the cause of all kinds of ALS, which is a complex disorder with many possible triggers. But in a 2019 study of postmortem brain samples, Dubnau and colleagues found that about one in five people with ALS had high levels of retrotransposon activation and TDP-43 dysfunction.

A link to tau and Alzheimer's

As that ALS story was developing, other scientists were pursuing a connection between retrotransposons and another toxic protein in neurodegeneration: the tau protein, which twists into unruly tangles in the brain cells of people with Alzheimer's disease. It affects retrotransposons because it, like TDP-43, plays a role in keeping retrotransposons quiet, says Frost.

That maintenance is a downstream effect of tau's association with the cell's interior skeleton. That skeleton is physically linked to the nucleus's skeletal structure, which in turn anchors the tightly wound-up DNA that silences retrotransposons. When tau goes bad, it changes the structure of the cell's main skeleton, making it more rigid. Frost and colleagues found that this structural defect propagates all the way to the nuclear skeleton and the chromosomes, just like tightening the strands on one side of a net could change the shape of the other side.

This structural effect can unlock the tightly wound bits of chromosome in fruit flies, which damages their neurons, Frost reported in 2014. By 2018, she'd shown that tau problems unleashed jumping genes in the flies.

"They were legitimately jumping," she says, going from their original chromosomal locations to other ones in the fly's brain cells. And the jumping genes contributed to the death of nerve cells.

Frost and colleagues also studied mammals — mice — and in 2022 they reported that retrotransposons were also activated in mice with dysfunctional tau.

Meanwhile, Frost and others examined brain cells from people who'd died of tau-related diseases such as Alzheimer's, which also revealed activated retrotransposons.

This awakening of retrotransposons appears to happen early in the disease, according to the work of another team published in 2022. In blood samples from people on their way to developing Alzheimer's disease, the copying of retrotransposon genes into RNAs spiked, creating a "retrotransposon storm," just before their symptoms got bad enough to be labeled Alzheimer's.

A tactic from HIV treatment

This growing body of evidence suggests that reactivating once-quiet retrotransposons, whether via dysfunctional tau or TDP-43, can create havoc. A potential treatment quickly comes to mind: Since these retrotransposons are a lot like viruses, scientists reason that antiviral drugs could help.

Handily, doctors already have medications that stymie retroviruses: Millions of people take antiretroviral drugs to keep HIV in check or prevent it from gaining a foothold in their cells.

Indeed, multiple studies over several years have investigated drugs from the HIV treatment playbook that block the enzyme reverse transcriptase. And in cells, flies and mice the drugs have dialed down retrotransposon activity and neurodegeneration.

These medications are well understood and generally safe, and are already in trials for neurodegenerative disease. For example, researchers have tested the safety of a 24-week antiretroviral course in 40 people with ALS. Not only did most people safely complete the trial, but the levels of HERV-K in their blood went down, and they seemed to have a delay in progression of their ALS symptoms, the researchers reported in 2019.

Frost recently published results from a small trial in which 12 people with early Alzheimer's disease took a reverse transcriptase inhibitor for 24 weeks. Her main goal was to determine if the treatment was safe, and it was — but the researchers also observed a drop in signs of inflammation in the participants' spinal fluid.

Both Dubnau and Frost serve on the scientific advisory board for Transposon Therapeutics, which tested its own reverse transcriptase inhibitor in 42 people with ALS and/or FTD. The company says the drug was tolerable and yielded signs of less neurodegeneration and inflammation, plus a delay in the inevitable worsening of symptoms. The company is planning a larger trial; it also plans to test its drug in people with ALS, Alzheimer's and a related tau-based disease, progressive supranuclear palsy.

Neither Frost nor Dubnau, who together recently summarized the field for the Annual Review of Neuroscience, believes that antiretroviral drugs alone are the solution to transposon-fueled Alzheimer's or ALS. As Douville notes, the drugs were designed to act only on specific target enzymes — they won't do anything to other retrotransposon genes, RNAs or proteins, which could also spur nerve-damaging inflammation.

Meanwhile, scientists are looking beyond ALS and Alzheimer's as evidence accumulates that retrotransposons may contribute to other neurodegenerative and inflammatory conditions, such as Parkinson's disease and multiple sclerosis.

"It's really picking up speed," Frost says.

This article originally appeared in Knowable Magazine, a nonprofit publication dedicated to making scientific knowledge accessible to all. Sign up for Knowable Magazine’s newsletter.

The new research, published Aug. 26 in the journal Nature Communications, mapped the emergence and progression of the cells and molecules that develop into the ovarian reserve in monkeys, from the early stages of ovarian development in an embryo to six months after birth.

This map fills in some of the blanks in "really important areas of just unknown biology," study co-author Amander Clark, a developmental biologist at UCLA, told Live Science.

Researchers can now use this map to build better models of the ovary in the lab to study reproductive diseases related to the ovarian reserve, she said, such as polycystic ovary syndrome (PCOS) — a complex hormonal disorder that can result in infertility.

Mysterious development

Ovaries are the primary female reproductive organs and play two essential roles in female health and reproduction: making egg cells; and making sex hormones, including estrogen, progesterone and testosterone.

Ovaries first begin to develop in embryos around six weeks after fertilization. In the early stages, germ cells — which develop into egg cells — divide and connect to one another in complex chains called nests. When these nests burst open, individual egg cells are released and are encased by a layer of specialized cells called pregranulosa cells, which support the young eggs and signal when it's time to mature.

These eggs encircled by pregranulosa cells are called primordial follicles, and are what make up the ovarian reserve.

Primordial follicles start to form around 20 weeks after fertilization, and cluster on the inside edges of the ovaries. When the follicles closest to the center of the ovary in these clusters mature, they grow and produce sex hormones.

So it is the primordial follicles that ensure the ovaries perform their jobs of producing mature eggs and releasing hormones, Clark said.

Multiple ovarian diseases and conditions are rooted in problems with the cells in the ovarian reserve. For example, although the exact cause of PCOS is still unknown, it involves dysfunction in the primordial follicles. And yet, very little work has been done to understand their development.

Building a map of how and when the ovarian reserve forms during pregnancy can help figure out why certain diseases and issues with fertility crop up later in life. "That's where this study came in," Clark said.

Related: 1st 'atlas' of human ovaries could lead to fertility breakthrough, scientists say

Surprise findings

To investigate how ovarian reserves originate in primates, Clark and her team looked at a monkey species that is physiologically similar to humans. This makes it a good stand-in for what happens developmentally in humans, she said.

First, female monkey embryos and fetuses were harvested at various developmental stages and ovarian tissue samples were taken. The researchers focused on several key time points: day 34 (when the sex organs become either male or female), 41 (early ovarian growth), 50-52 (end of embryonic period), 100 (when the egg nest expands) and 130 (when the nest bursts and the primordial follicles form) after fertilization.

Then, the team analyzed the position and molecular fingerprint of the ovarian cells to understand the critical events in the formation of the ovarian reserve.

They found that pregranulosa cells formed in two waves, but it was only during the second wave, between days 41 and 52, that pregranulosa cells formed that would go on to swarm the young eggs to form primordial follicles.

They also identified two genes that seem to be active prior to this second wave. The researchers said that looking further into the function of these genes may help to pinpoint the developmental origins of ovarian reserve problems.

Also, Clark said the team was completely surprised to find that "before birth, the ovary goes through practice rounds of folliculogenesis," meaning that very soon after the ovarian reserve is made, some of the more centrally located follicles mature and can produce hormones. The researchers suggest that determining why these follicles normally activate could provide insight into the causes of PCOS.

Still, the researchers are looking at a highly dynamic period in development, when the cellular makeup of an embryo can change dramatically, Luz Garcia-Alonso, a computational biologist at the Wellcome Sanger Institute who was not involved in the study, told Live Science in an email. And they have big time gaps between their observation periods.

"This stage when cell lineages are specified is very dynamic, and cell composition changes within days," Garcia-Alonso said. So the team should collect more fine-scale data on more time points to get a better picture of what is going on, she added.

This article is for informational purposes only and is not meant to offer medical advice.

The experiment, which took place in Guangzhou, China, kept the lungs alive and working for nine days, despite showing signs of rejection early on in the procedure. The researchers behind the study say that their work "paves the way for further innovations in the field," although questions remain about how successful such a procedure could be for a living patient removed from a life support machine.

Elsewhere, another study has found a potential route to laser-free vision treatment by zapping the eye's surface into a new shape using an electrical current. And researchers also found a link between gum disease and cardiovascular disease, with treatment reducing the narrowing of the carotid artery in otherwise healthy individuals.

Starship nails test flight

10th time lucky! SpaceX's Starship nails successful test flight after string of explosive setbacks

If at first your gigantic rocket explodes… explode it again and again until you succeed. That's been SpaceX's "fail fast, learn fast" ethos since it began development of its Falcon 9 rocket 20 years ago, and it finally paid off for its largest rocket, Starship, as it nailed a successful test flight this week.

The 10th test flight marks a comeback for the company after a string of explosive failures, some of which littered the Caribbean with debris. It came just in time for the company, and for NASA too — the rocket, the largest ever built, is key to ambitions to transport crewmembers, spacecraft, satellites and cargo into orbit around Earth, with a moon mission planned as early as 2027.

Discover more space news

— James Webb telescope images reveal there's something strange with interstellar comet 3I/ATLAS

— 'Potentially hazardous' asteroid Bennu contains dust older than the solar system itself — and traces of interstellar space

— NASA reveals the dwarf planet Ceres had a hidden 'energy source' that may have sparked alien life

Life's Little Mysteries

What is the world's slowest animal?

Cheetahs, marlins, peregrine falcons — fast animals get all the fame. But what about the slowest animals? And how do they survive in the wild while moving, literally, at a snail's pace? Here's our investigation into how Earth's most unhurried animals live life in the slow lane.

— If you enjoyed this, sign up for our Life's Little Mysteries newsletter

Strange science

Scientists cram an entire computer into a single fiber of clothing — and you can even put it through your washing machine

Scientists have created a flexible, machine-washable fiber that can perform computing tasks. In theory, that means they could one day weave them together to form a "fiber computing network" made up of smart textiles.

These fibers have historically had limited computing ability, and scientists weren't able to embed multiple types of electronic components into them.

The new material weaves eight devices into a single fiber strand, including a photodetector, a temperature sensor, an accelerometer and a photoplethysmogram (PPG) sensor, which measures changes in light absorption by the skin. The material is also elastic, which makes it practical for clothing applications, the researchers say.

Also in science news this week

— Keratin extracted from sheep's wool repairs teeth in breakthrough

— 'This technology is possible today': Nuclear waste could be future power source and increase access to a rare fuel

— New brain implant can decode a person's 'inner monologue'

— Mystery quake that rocked Northern California in 1954 came from 'eerily quiet' Cascadia Subduction Zone

Beyond the headlines

'Aging clocks' tell you how much 'older' you are than your chronological age. How do they work?

There's the number of candles you blow out on your birthday cake, and then there's your "biological age," a measure of how much your biological systems have broken down over time. In other words, how well do your cells, organs and body systems work compared to a typical, healthy 40-year-old?

A number of scientists have touted their ability to measure this biological age with "aging clocks." These clocks often work by using AI to glean patterns from hundreds of biomarkers, or indirect measures of health, taken from large groups of people. They then compare a person's biomarkers against this aggregate group to pin down the biological age.

But can they really predict disease, and are the results reliable for commercial use?

Something for the weekend

If you're looking for something to do over the weekend, here are some of the best polls, book interviews and crosswords published this week.

—Live Science crossword puzzle #7: NASA mission that redirected an asteroid — 8 across [Crossword]

— Do you trust AI? [Poll]

— 'I would never let a robot incubate my child': Poll on 'pregnancy robots' divides Live Science readers [Poll results]

Science in pictures

Heartbreaking image shows a sloth clinging to a barbed wire fence because it was the closest thing resembling a tree

A sneak peek of the shortlisted 2025 Wildlife Photographer of the Year competition entries was released this week, featuring a heartbreaking shot of a sloth clinging to a wooden post, a lioness staring down a cobra, an ethereal jellyfish swarm, and clouds reflected in salt ponds in San Francisco Bay.

Follow Live Science on social media

Want more science news? Follow our Live Science WhatsApp Channel for the latest discoveries as they happen. It's the best way to get our expert reporting on the go, but if you don't use WhatsApp we're also on Facebook, X (formerly Twitter), Flipboard, Instagram, TikTok, Bluesky and LinkedIn.

The supposed CEO of the robot company reportedly proclaimed that the development of the robot was close to completion, and that a prototype would be ready as early as 2026. While the story was pure fiction, it sparked a discussion about whether such technology is feasible — or ethical.

Around 180 readers responded to our poll, which was published on Aug. 23. As of today (Aug. 29), results show 30% of responders would use a pregnancy robot as long as they were sure their baby was healthy and not harmed by the process, while 29% of responders selected no, with the opinion that the process is completely unethical.

11% of respondents said they would use a surrogate robot with no questions asked, while 8% expressed doubts that the technology would keep a baby safe during development.

"I would never let a robot incubate my child. I just don’t think a robot could ever give a baby everything it needs to develop properly," Rene wrote. "There’s something about that natural bond between a mother and her baby — maybe even a brain-to-brain connection — that feels too important to replace."

For some their decision was based around ethical views. "This is just more anti human science that will only further our fall as a civilization," Thatguy wrote, describing the technology as "disgusting" and "repulsive."

On the other side, ShanMorgain suggested it could help mitigate some of the risks associated with pregnancy. "Omigod YES. Pregnancy and birth are atrocious and escaping their blight — which can mean lifelong damage — would be wonderful. Some would choose the natural method fine for them. I loved the idea when I met it in Lois McMaster Bujold's 'Vorkosigan' series. Her imagined incubator is mobile and can stay close to the parents. Big impact on gender equality."

Below, you will find three Labor Day smartwatch deals so good we would happily invest in them ourselves. You can trust our choice here — we have personally tried and tested dozens of fitness trackers, so we know which models are truly worth your hard-earned money and which are better given a miss. Plus, we made sure that these are the lowest prices around, so you can shop with confidence.

Let's start with our favorite smartwatch deal we found, the Withings ScanWatch 2. This ultra-stylish smartwatch is now 19% off at Amazon, and the cheapest it has been since February. If you are tired of the bulky, sporty-looking Garmin watches, the Withings ScanWatch 2 will be right up your street. It is discreet, beautifully crafted and, if our experiences with the brand are anything to go by, also very accurate and long-lasting.

Then, there is this excellent deal on the Samsung Galaxy Watch 7 — the price of this popular Android smartwatch has just been slashed by 25% at Walmart. The Samsung Galaxy Watch 7 offers excellent health-tracking features, customizable designs and a myriad of third-party apps, making it an excellent all-rounder and a top pick for those with Samsung Galaxy phones. At just $187, it is a steal.

Lastly, we have this massive Walmart deal on the Garmin Fenix 7X Sapphire Solar — this premium outdoor smartwatch is now a whopping $350 off. True, the Garmin Fenix 7X Sapphire Solar has seen many discounts recently (mostly due to the release of the newer, more advanced Garmin Fenix 8 several months ago), but not every day do we see its price go under $650. If you are after a reliable companion for your outdoor adventures, we can't recommend this watch enough.

Specs-wise, the Levoit Sprout seems to tick all the boxes for new parents. Most importantly, it features a three-stage air filtration: a pre-filter designed to capture large airborne particles such as dust and pet hair, a True HEPA filter that removes 99.9% of particles as small as 0.01 microns, and an activated carbon filter that eliminates odors, fumes and volatile organic compounds (VOCs). Moreover, it tracks a wide range of airborne pollutants as well as temperature and humidity, going above and beyond what most air purifiers can do in that regard, plus it can be controlled remotely via the VeSync app. The Levoit Sprout also features a white noise machine and a night light. In theory, it could be an excellent multi-purpose appliance for nurseries — but how does this air purifier perform in practice, and is it worth the $279.99 price tag?

Levoit Sprout air purifier review

Levoit Sprout: Design

• Toddler-friendly design
• Small, light and portable
• Tiny icons on the control panel

The best word to describe the Levoit Sprout? Cute. With its cylindrical shape and white-blue color scheme, it reminded us of Olaf, the talking snowman from Disney's "Frozen" franchise. We could not think of a better look for a baby's nursery. But it’s not just nice to look at, but also practical.

First and foremost, it is relatively kid-proof. The Levoit Sprout has no sharp edges or protruding elements, and thanks to its unique shape, it is quite difficult to tip over. If it does fall, though, it is unlikely to cause substantial harm. Weighing only 6.4 lbs (2.9 kg) and measuring just 14 inches (35.5 cm) in height, it is one of the smallest and lightest air purifiers we tested.

Secondly, the Levoit Sprout is easy to move around. Most people would be able to grab hold of it with one hand. If you are a parent trying to juggle multiple tasks at the same time, this portability can prove very useful on a day-to-day basis. The cable can also be easily detached from the plug at the back of the unit, so there is no need to wrestle with the appliance should you wish to move it to another room.

Lastly, the Levoit Sprout is easy to operate via the control panel and a small but easy-to-read display at the top of the unit. Our only gripe was with the visibility of the icons. They are tiny, and because they are white and placed on a light grey background, these icons are not particularly clear to see, even from a relatively short distance.

We also liked the straightforward design of the filter chamber. It took us less than 30 seconds to install the filter, and all we had to do was unscrew the top half of the air purifier, take the plastic wrapper off the filter, and pop it back in. Speaking of filter replacements, they cost $39.99 and last approximately six to eight months. While they are quite expensive for air purifiers in general, they are priced similarly to other filter replacements made by Levoit.

Levoit Sprout: Features

• Built-in white noise machine and night light
• Four fan speeds and an auto mode
• Detailed air quality monitoring

With four fan speeds, an auto mode, a timer and a scheduling option, the Levoit Sprout does not stray far from its coveted siblings, the Levoit Core 600s or the Levoit Vital 200S. Feature-wise, this air purifier is just as easy to set up and control. However, this is where the similarities end.

For example, the Levoit Sprout offers more in-depth air quality monitoring. Most Levoit air purifiers can only track airborne particles that measure 2.5 microns (pollen, certain mold spores and smoke particles, for example), and while it is a relatively good indicator of air pollution in general, it does not convey the full picture. The Sprout, on the other hand, can also track airborne particles that are as small as 1 micron (such as some bacteria and dust mite allergens) and those as big as 10 microns — mold spores and some types of smoke, for example. In addition, this air purifier tracks TVOC (Total Volatile Organic Compounds), temperature and humidity.

That said, the Levoit Sprout offers only real-time air quality measurements. It will not give you historical readings or reports on how the air quality has been changing over time. It is quite a significant oversight given that many air purifiers in this price range, including some other ones made by Levoit, allow you to access that information.

Finally, the baby-friendly features. As we mentioned before, the Levoit Sprout does not just clean the air — it can also help put your baby to sleep. This air purifier can play five different sounds, including white noise and a soothing lullaby, all of which can be adjusted across a relatively wide volume range. On top of that, the Levoit Sprout can serve as a night light, and since its built-in lamp does not emit blue light, it should not be too disruptive to your baby's wake-sleep cycle.

Levoit Sprout: Performance

• Quiet at low fan speeds
• Ultra-sensitive particle sensors
• Efficient at removing airborne pollutants in small spaces

Air pollution is a serious concern for new parents. Studies have shown that long-term exposure to coarse particulate matter — dust, ash and some smoke particles, for example — can put babies at an increased risk of early death. Not to mention, there appears to be a strong link between air pollution and childhood respiratory diseases, according to a 2023 review published in the International Journal of Molecular Sciences. Therefore, we consider air-cleaning performance to be the crucial aspect of any air purifier that is meant to be used around infants and toddlers. The Levoit Sprout fell slightly short of expectations here.

According to the brand, the Levoit Sprout is best suited for spaces up to 639 square feet (59.4 square meters). However, this only applies if the air in that space is cleaned once per hour. For best results, most air quality experts suggest at least four air changes per hour. So, we took it upon ourselves to calculate what room size the Levoit Sprout is best suited for.

To do that, we took note of its CADR ratings. These metrics, measured in cubic feet per minute (CFM), can tell you how quickly an air purifier can clean the air in a given space. As a rule of thumb, the CADR should be at least two-thirds of the room's square footage. The Levoit Sprout is rated 85 CFM for smoke, 109 CFM for pollen and 152.9 CFM for dust. Based on these CADR values, the Levoit Sprout is likely to perform best in rooms measuring around 80 - 100 square feet (7.43 - 9.29 square meters) — much lower than advertised.

That is not to say the Levoit Sprout is a bad air purifier, quite the opposite. When used in spaces that are in line with these CADR ratings, it does a great job of removing airborne pollutants. To fully assess its air-cleaning performance, we performed a series of tests using an industry-grade Perfect Prime air particle counter, a handheld device capable of detecting airborne pollutants as small as 0.3 microns. The results speak for themselves.

First, we performed an ambient air quality test. We placed the Levoit Sprout in a small, enclosed room (approximately 9 square meters) and ran it on Auto mode for 30 minutes. After just 15 minutes, this air purifier removed 65.5% of particles smaller than 0.3 microns and 84% of particles measuring 2.5 microns (no 10-micron pollutants were detected). After 30 minutes, these values rose to 92% and 99%, respectively. Given that these tests were conducted on a day when air quality was deemed very good, these results are quite impressive.

We then burned a handful of matches to assess how well this purifier absorbed smoke. After 30 minutes of running in Auto mode, the Levoit Sprout removed an impressive 96.8% of particles smaller than 0.3 microns, 98.9% of 2.5-micron particles and all of the pollutants measuring 10 microns. When we rerun this test at the highest fan speed, the results were almost identical.

Finally, we challenged our Levoit Sprout to incense smoke. We burned a handful of sticks, then ran the air purifier on Auto mode for 30 minutes. Within half an hour, the Levoit Sprout absorbed 99.2% of particles smaller than 0.3 microns, 99.8% of 2.5-micron pollutants and 100% of particles measuring 10 microns. Just like in the match tests, we obtained similarly good results when we rerun the test at the highest fan speed.

All in all, the Levoit Sprout does a great job getting rid of different types of air pollution — as long as it is used in small spaces, that is.

One of the reasons why the Levoit Sprout appears to be performing so well may lie in its air quality sensors. We found them to be exceptionally sensitive. Oversensitive, even. On three separate occasions, we compared the air particle counts obtained with our handheld air particle monitor with the values displayed by our Levoit Sprout and found that our air purifier overestimated slightly nearly all of them. Now, this can be both good and bad. On the plus side, the Levoit Sprout is less likely to underperform when it is needed the most. On the other hand, it could make the parents way more worried about the state of their indoor air quality than they need to be.

Last but not least, the noise levels. The Levoit Sprout is almost silent at the lowest fan speed, so it is unlikely to wake up a sleeping baby. When it comes to the highest fan speed, however, it is more difficult to assess. When we measured its noise levels using the Sound Meter decibel-counting app, we did not note a reading higher than 48 dB. This is equivalent to a humming refrigerator or quiet office, and significantly lower than many of the air purifiers we tested before. That said, this may still be too noisy for some light sleepers.

Levoit Sprout: User reviews

The Levoit Sprout scores a solid 4.4 out of 5 stars at Amazon. This air purifier is universally praised for its detailed air quality measurements, efficient air purification and compact size. Negative comments, on the other hand, often revolved around its expensive price, and a couple of users complained about their defective units.

As one happy buyer commented, "This purifier is perfect for parents who appreciate having real-time data on air quality. It’s super powerful, taking air quality from unhealthy to healthy in a matter of minutes! It’s a must-have, we run it 24/7, and we may buy a second one for our bedroom! It’s a great size for our nursery, easy to use, and very quiet at lower levels. It’s pricier than others, but you get the quality you pay for!"

Should you buy the Levoit Sprout?

✅ Buy it if: You are looking for a multi-purpose air purifier for a small nursery or toddler's bedroom. The Levoit Sprout does an excellent job of removing airborne pollutants in spaces up to 100 square feet (9.29 square meters), without making much noise or requiring extensive maintenance. It is also portable, good-looking and easy to use, and unlike many other air purifiers designed with infants in mind, the Levoit Sprout features a built-in white noise machine and blue-light-free night lamp.

❌ Do not buy it if: You want an air purifier for large spaces, something affordable, or an appliance that can keep records of your air quality data over time. There is a lot to like about the Levoit Sprout, but it is not powerful, functional or affordable enough to fully justify its high price.

If Levoit Sprout is not for you

While we can't think of any appliances that would have exactly the same functionality as the Levoit Sprout, there are several appliances that could be of interest to new parents. The Thule Shine Canopy, for example, is the first ever stroller accessory designed to filter out air pollutants on the go. We found it to be discreet, easy to use and very effective at cleaning the air. However, it is only available in Europe and in the UK at the moment, and it does cost nearly €500 ($580).

If you would rather stick to classic standalone units, consider the Levoit 400S Core instead. This air purifier is of a similar size to the Sprout, and it works using the same app, but it is more powerful and cheaper by around $60.

Looking for something bigger? The BlueAir Classic Pro CP7i is another great alternative. Immensely powerful, ultra-quiet and equipped with innovative germ-busting HINS technology, it is a great choice for large spaces. That said, it costs almost $200 more than the Levoit Sprout.

Levoit Sprout: How we tested

We spent over a month testing the Levoit Sprout air purifier, assessing its design, functionality, day-to-day performance, ease of use and connectivity with third-party devices. We also measured how loud this appliance was on different settings using the Sound Meter decibel-counting app, and checked the cost of the replacement filters.

Lastly, we performed a series of tests using an industry-grade Perfect Prime air particle counter, a handheld device capable of detecting airborne pollutants as small as 0.3 microns. We started with an ambient air quality test, where we ran the Levoit Sprout on its auto mode for 15 and 30 minutes, and noted the differences in the air quality measurements over time. Next, we conducted several smoke tests. We burned matches and incense sticks to create severe pollution, then recorded the changes in air quality readings after running the Levoit Sprout for 15 and 30 minutes on auto mode and the highest fan speed.

Chronological age is the number of years between your birth and now; it's purely time-based. Biological age, on the other hand, describes the progressive breakdown of an individual's physiological and molecular systems over time; it's a measure of how "aged" the body is. The calculation aims to answer the question of how well your systems, organs and cells are working compared to an average, healthy baseline.

"Biological age is notoriously hard to define because it's very much a conceptual notion," said Eric Sun, an assistant professor of biomedical engineering at MIT, where he will launch a new lab starting in 2026. The concept requires you to think less about pure chronology and more about how your body is performing over time, and what your risks and vulnerabilities for various diseases might be in the future, he said.

Scientists have devised a number of "clocks" aimed at determining people's biological ages. Here's how they work and why they might be useful.

Neither Henderson nor Sun thinks modern aging clocks are ready for clinical use. There's still too much noise in the data, too much potential for drawing faulty conclusions about what drives aging and what's just associated with it, Henderson told Live Science. If aging clocks were used to help doctors determine what treatment course a patient needs, false positives could lead to unnecessary medical intervention.

Sun told Live Science he believes future clocks that get adapted for patients will bear similarities to the fourth-generation causal clocks that already exist.

"It won't just be biomarkers for how your entire body or even individual systems are aging," he said, "but multiple biomarkers for different functions within an organ."

This article is for informational purposes only and is not meant to offer medical advice.

Formaldehyde — as well as liquid forms of the chemical, called formalin and methylene glycol — is added to hair-straightening and hair-smoothening products as a preservative to extend shelf life and to help lock the hair's texture in place for a long time.

However, in recent years, various countries have moved to ban the chemical from hair-straightening products due to health concerns.

When heated, as it is during these hair treatments, formaldehyde is released into the air as a gas. This can cause immediate problems, such as skin irritation, coughing, wheezing and a burning sensation in the eyes. But especially when it happens repeatedly, formaldehyde exposure can also cause long-term issues such as fertility problems, asthma and a raised risk of cancer, such as leukemia and nasopharyngeal cancers.

Given these issues, formaldehyde-free versions of these products are often touted as safer options. But that doesn't mean they're harmless, according to the new case series, published Aug. 28 in the journal Clinical Toxicology. In particular, the report highlights a potential risk of kidney injury tied to glyoxylic acid, an ingredient found in many formaldehyde-free hair-straightening products that serves as a straightening agent.

The report details the cases of 13 women and teens who were treated at the Sourasky Medical Center in Tel Aviv following exposure to formaldehyde-free hair-straightening products. The patients began feeling ill within two to 72 hours of undergoing these hair-straightening treatments at various salons.

"Even before these studies were published," the study authors wrote, "our medical toxicology service had begun to receive similar reports, prompting us to visit local hair salons, including illegal salons mentioned by affected patients, where we discovered the presence of glyoxylic acid in the hair-straightening products."

Related: Hair-straightening products contain chemicals that boost risks of cancer, kidney injuries and breathing issues

The 13 patients, who ranged from 15 to 53 years old, developed symptoms such as vomiting, abdominal pain and scalp rashes. Twelve of the patients developed acute kidney injury, as evidenced by a buildup of the waste product creatinine in their blood, a decrease in urine output and the presence of small crystals in the urine they did expel.

The one person who didn't develop kidney injury had received treatment very quickly — they were admitted to the hospital just six hours after their hair treatment, and within two hours of admission received thiamine and pyridoxine, which are B vitamins thought to help the body break down glyoxylic acid.

In addition to finding glyoxylic acid-containing products at the salons their patients visited, the medical center's toxicology team also found that some of the salons had inadequate ventilation.

The patients stayed in the hospital for between one and 10 days. None of the patients required their blood to be filtered with hemodialysis and no deaths occurred.

It’s worth noting that the case series included relatively few patients, didn't include any kidney biopsies and was in part conducted retrospectively, as the authors looked back at cases that took place between April 2021 and March 2025. However, this isn't the first time glyoxylic acid has been linked to kidney issues. Hair products containing the ingredient have been tied to kidney injuries in anecdotal reports and in one woman's case of repeated kidney damage, for example.

"These findings highlight a potentially underrecognized risk of kidney toxicity associated with glyoxylic acid-containing hair products," the authors concluded. "Prompt recognition and early treatment, particularly with thiamine and pyridoxine, may reduce the severity of kidney damage. Further studies and regulatory action are needed to better define the risk and prevent future cases."

Meanwhile, in the U.S., the Food and Drug Administration (FDA) seemed poised to ban formaldehyde in hair-straightening and hair-smoothing products back in April 2024. However, the proposed ruling was postponed several times in 2024, and the effort has not progressed in 2025. For now, the FDA simply discourages consumers from purchasing and using hair products containing formaldehyde or related ingredients.

Some experts have said that glyoxylic acid should also be banned from hair-straightening and smoothening products, but no moves have been made on that front.

This article is for informational purposes only and is not meant to offer medical advice.

It has numerous higher-end fitness and running features, and as of June 2025, it is the brightest Garmin watch we’ve ever used. The Forerunner 970 flourishes in the summer, even if you do have to pay for that clarity in battery life. Under heavy use, the Forerunner 970 won’t last nearly as long as some older Forerunners.

The Forerunner 970 is also perhaps a little pricey for UK buyers, at $749.99/£629.99. That is $150/£30 more than the predecessor Forerunner 965’s $599.99/£599.99, which was one of the best high-end fitness watch deals of its generation.

There’s a bit of a sting for US buyers, but a much less pronounced one for those in the UK.

Garmin Forerunner 970 review

Garmin Forerunner 970: Design

The Forerunner series is home to some of Garmin’s most practical and easy-to-recommend watches. Its Garmin Forerunner 970 tests that premise, being the most expensive of the lot. But this is still an easy-to-like design.

It doesn’t have the bulky, intimidating appearance of Garmin’s adventure-bound Instinct watches, and the mostly-plastic build keeps the weight to a light 56g.

Think it’s crazy to spend this much on a plastic casing watch? That’s just part of the bargain when you buy a Garmin.

This is an ultra-tough polymer, though, and there are metal touches throughout. The Forerunner 970 has a titanium bezel with a matt finish on its front-facing edge. All the buttons are metal, too, as is the little lime green Forerunner panel on the side.

A truly ultra-rugged design is what the Forerunner 970 lacks. The bezel does not sit significantly proud of the screen, a design used in some Garmin models to help deflect surfaces and objects away from the screen glass.

Now, several weeks into using the Forerunner 970, we would also advise against thinking titanium means the bezel won’t get damaged. We’ve already put a few scrapes into its matt surface. Oddly enough, we tend to find it’s Garmin’s “polymer” plastic watches that often age the best.

The main body of the Forerunner 970 is made of this plastic polymer and appears to be a single piece of it. This watch also only has 5ATM water resistance, not the 10ATM of the Fenix 8. It’s a reminder that Forerunner is a runner-first series, even if Garmin does also recommend this series for triathletes.

It’s easily tough enough and rugged enough for most, myself included, but doesn’t have a laser focus on being abuse-ready compared to more adventure-ready families like Garmin Instinct. That said, the jump to Sapphire crystal display protection is a big boost over the Gorilla Glass of the previous Forerunner 965.

There’s also no size option beyond 47mm in diameter. We are perfectly happy with this size, but if you prefer a more petite watch, you may well prefer something in the 40-42mm bracket. There’s the pricier Fenix 8 (43mm) or the lower-end Forerunner 570 (42mm), for example.

Garmin Forerunner 970: Features

The Garmin Forerunner 970 has just about every feature you could ask for, bar the dive-ready water resistance Garmin added in the Fenix 8.

On-watch maps are one of the key things you’re paying for, above the step-down Forerunner 570. You can download whole continents’ worth to the 32 GB internal storage.

With a cheaper Forerunner, you can still transfer planned routes to the watch for navigation but here you can see full colour maps as you go. We’ve done this a few times during testing, and it. It might be the best such experience we’ve ever had with a Garmin watch.

Why? The Forerunner 970 has a great mapping display screen that provides the map plus some essential stats — all you need. And this thing’s 1.4-inch AMOLED screen is exceptionally bright. In more than a decade of reviewing wearables, we’re not sure display brightness has ever stood out to me as much as this.

The Forerunner 970 really goes for it too, making the screen look ultra-clear on bright and sunny days throughout multi-hour workouts rather than playing safe to conserve power. It feels positively indulgent, even if it does predictably have an effect on battery life. More on that later.

Garmin has also done its best to blend the sense that the Forerunner 970 is a hardcore runner’s watch and also a lifestyle device. It bookends your days with Evening and Morning reports, which show the upcoming weather, your calendar and — the really important bit — your suggested workout for the next day.

Morning Report has been around for yonks but the Evening one is newer. And we find it can be useful when Garmin suggests a tougher workout. Who doesn’t need some mental preparation time for a sprint session?

What’s specifically new for the Forerunner series is the Forerunner 970’s combo of a speaker and mic. This enables two flavours of voice-prompted assistant.

Voice Command lets you control parts of the watch. That might be starting a run session, increasing screen brightness, or using the Find My Phone feature. But the part that’s actually useful? Setting timers. The best bit: the Forerunner 970 can do this all without being connected to your phone, which is neat.

The Forerunner 970 can also be used as a conduit to your phone’s own assistant. This is less exciting, though, as the watch itself isn’t really doing any of the work. And neither of these voice assistant modes feels immediate. There’s a short wait while you hope it’ll work.

Additionally, the Forerunner 970 has a flashlight, which used to be the preserve of Garmin’s bulkiest watches. Up on the top sidewall of the watch, easy to miss, there are two white LEDs and a red one, used when you don’t want to cast too much light and just need to see your near-field surroundings.

The Forerunner 970 has an adventurer’s edge after all.

It also introduces a few new stats, alongside the long-running (and super-useful) Training Readiness and Training Load. The Forerunner 970 adds Running Tolerance, which is a stat — expressed in km. But it’s not just the amount you’ve run. Harder running has a greater km value.

Right now, the Forerunner 970 says we have a running tolerance of 91km a week, and that we are currently at 81.8km for the last seven days. But we’ve only actually run 73km.

Is messing with a concrete stat like weekly distance questionable? Sure, but we have found it a useful way to, fingers crossed, avoid injury through overdoing exercise.

On the health side, the Forerunner 970 also provides ECG readings to look for signs of arrhythmia. This is only available in a few high-end Garmin devices so far, and does require activity participation, a 30-second session where you place your thumb and forefinger on the metal bezel.

Garmin Forerunner 970: Performance

The Garmin Forerunner 970 is a lot like the Fenix 8 in use, which is no surprise when they share the same level of internal tech.

GPS lock-on takes a few seconds — not instant but fast enough not to become annoying — and the route maps it produces are highly accurate. You may get even better results if you use the more battery-sapping dual-band GPS mode, present here.

We’ve used the Auto mode during testing, which claims to be able to tell when the powerful dual-band mode is needed, then switch to it.

Heart rate accuracy is very good for running, too, but as with every other high-end Garmin, it’s not perfect for weight-based gym sessions where your heart rate rises and falls within the space of a minute. The Forerunner 970 still massively outclassed the Sunnto Run we’ve tested alongside the Garmin, but results were far better with a Garmin HRM 600 chest strap worn at the same time.

As with most Garmins, you can connect a chest strap to the Forerunner 970 wirelessly if you like.

We’re basically looking at a quality level the best Garmin has to offer in terms of GPS and HR accuracy, which is also among the best found in any wearable at present. It gets an A-grade for running, maybe a C+ for gym work.

Sleep tracking is good too. The Forerunner 970 can always tell when we’ve had a few glasses of something the night before, and notices the loss of sleep quality, although it does tend to miss wakeful moments at times — even if they include walking to the toilet.

Earlier, we suggested that the very high screen brightness has an effect on battery life, and it means we personally haven’t come close to Garmin’s claim of 15 days of battery life. With the always-on mode switched on, it’s closer to 4-5 days. And we’ve found tracked outdoors exercise can eat up to 7% an hour — the variance depends on how your interactions with the wash push it to its highest brightness mode.

Is Garmin’s 15-day claim a fake, then? No, but there are more factors to bring it down than before. And even if you lower the display brightness setting, it will still put out a good amount of power when in direct sunlight.

Garmin Forerunner 970: User reviews

The Garmin Forerunner 970 has received almost universally positive user reviews so far online.

One complaint is that the “always-on display” mode is not very visible when outdoors. This is where the watch displays the time even when the watch is sitting idle on your wrist.

The Forerunner 970’s brighter screen actually highlights this effect by increasing the disparity between the brightness level when the watch is used and left hanging around on your wrist.

Should you buy the Garmin Forerunner 970?

The Garmin Forerunner 970 is a terrific running and fitness watch we’re comfortable recommending to many, with a few caveats.

It doesn’t feel quite as high-value a package as the older Forerunner 965 for US buyers. That older model was probably the easiest-to-recommend high-end Garmin watch of the last generation.

We get more smart features, even greater teasing out of stats. But the core proposition is pretty similar. And its neatest trick, supernova brightness, does make real-world stamina worse than last time around.

Does that matter when it genuinely enhances the experience? Maybe not, but it does reinforce that the Forerunner 970 is better suited to those who exercise around a regular routine rather than spending weekends (or weeks) away in the wilderness, where charging opportunities may be less forgiving.

If the Garmin Forerunner 970 is not for you

Put off by the price? It’s worth seeing if you can hunt down a deal on the Garmin Forerunner 965. It’s an older watch without this one’s screen brightness and older software. But it does have most of the core features we care about most, for less.

You may also want to consider dropping down to the Forerunner 570, although we actually find the value issue more glaring in that watch. The two were released at the same time, and that one lacks features like maps and ECG readings, and uses cheaper glass and metal for the bezel and screen.

How we tested

The Garmin Forerunner 970 was worn consistently for more than two weeks during testing. Most days it was used to track a run, and around three times a week it was used to track gym sessions. It took a rainy London day festival like a champ, and was worn most nights to assess sleep tracking. Testing also included switching between the Forerunner 970’s “always on” screen mode and the default “raise to wake” to get the best idea of battery life.

Likely by reducing inflammation, this routine oral hygiene procedure may be an unsung way of minimizing declines in blood vessel functioning.

"I was very overwhelmed when I looked at the data the first time," study co-author Dr. Marco Orlandi, a clinical research periodontist at University College London, told Live Science.

Around 40% of U.S. adults ages 30 and older have some level of gum disease, known as periodontitis, a chronic inflammatory condition whose progression leads to wobbly teeth, tooth loss and persistent bad breath. As the disease worsens, small pockets around the teeth that cannot be reached by a toothbrush or floss expand and fill with plaque and bacteria.

There is now an abundance of research linking periodontitis to a higher risk of various health outcomes, including Alzheimer's disease, colon cancer and rheumatoid arthritis. A key area with mounting evidence is the association between severe gum disease and cardiovascular disease, with previous studies finding that the management of gum disease is linked to improved blood vessel function.

Now, a clinical trial published Aug. 19 in the European Heart Journal has found that treating periodontitis slows the thickening of the inner two layers of the carotid arteries, found on each side of the neck, in otherwise healthy adults. The thickness of those artery walls is a key marker for cardiovascular disease risk.

Related: Keratin extracted from sheep's wool repairs teeth in breakthrough

By targeting inflammation rather than other artery health factors, like cholesterol, "the impact of what we are doing comes without going through the classic risk pathway" for cardiovascular disease, Orlandi said.

To test whether treating periodontitis actually causes the carotid arteries to thicken less over time, Orlandi and his team of periodontists and cardiologists conducted a gold-standard trial at a dental hospital in central London. The trial was randomized, meaning participants were randomly placed in a treatment group or a comparison group that didn't receive the intensive gum treatment.

First, the researchers took ultrasounds of the carotid arteries of 135 people with severe periodontitis, to establish a baseline level of thickness. They also measured how much the arteries dilated when blood flow increased — a measure of blood vessel functioning — and took blood samples to pinpoint markers of inflammatory and oxidative stress. All of the individuals were healthy besides having gum disease.

Next, the participants were randomly divided into either the treatment group or the control group. Care was taken to ensure there was a roughly even split between the two groups in terms of the participants' periodontitis severity, smoking status and family history of cardiovascular disease.

In the treatment group, patients received intensive periodontitis treatment: a thorough clean of the whole mouth and a deep clean below the gumline to remove plaque and tartar. The control group received a simple scale and polish, more akin to a regular dental cleaning that doesn't include a deep clean of the gums.

The participants were then followed for two years, and they each received further dental treatments at regular intervals throughout that time. The researchers also reassessed the carotid artery at the one-year and two-year marks, and took blood samples and measured blood-vessel function at five time points.

They found that the thickness of the carotid arteries' innermost linings was lower for individuals who received intensive treatment than for those in the control group. This difference was "comparable to what has been seen with lifestyle interventions and some pharmacological agents in similar populations," study co-author Dr. Francesco D'Aiuto, a clinical research periodontist at University College London, told Live Science in an email.

The treated patients also had better blood vessel function and lower levels of inflammatory and oxidative stress markers in their blood, which are known to contribute to the narrowing of artery walls — a condition called atherosclerosis.

Although many factors drive atherosclerosis, "our results reinforce the view that untreated periodontitis is a modifiable risk factor for vascular ageing and possibly cardiovascular events," D'Aiuto said.

However, a key limitation of the research is that it was conducted in only one location, so there is a chance that the findings partly come down to quirks of the location or the people in the sample, Orlandi said.

Another limitation, said Dr. Maurizio Tonetti, a clinical and research periodontist at the University of Hong Kong who was not involved in the research, is that all of the participants in the trial were healthy other than having periodontitis. As such, these results should not be interpreted as evidence that if someone with atherosclerosis has their gum disease treated, the health of their arteries will improve, he told Live Science.

Even so, the findings "are bringing the concept of these [intensive gum disease] interventions into the preservation of wellness," Tonetti said.

"For many, many years, dentists have been focusing on the teeth, forgetting the rest of the body, and physicians have been focusing on the body, forgetting that there are teeth," he said. "They are really two worlds that have been separated and need to go back together for the benefit of patients."

This article is for informational purposes only and is not meant to offer medical advice.

The method has so far been tested only in animals, but the researchers who pioneered it hope that it will someday offer an alternative or complement to conventional LASIK surgery. The team presented their findings Aug. 18 at the American Chemical Society's annual meeting in Washington, D.C.

LASIK is the most popular type of "refractive" laser surgery, which adjusts how light passes through the clear outer layer of the eye, or cornea. It can correct the changes in the cornea that cause nearsightedness, farsightedness and astigmatism. For those looking to ditch glasses or contact lenses, LASIK has become a common solution: since its approval in 1999 this surgery has treated more than 10 million people in the U.S.

The cornea bends light to focus it on the retina, the light-sensitive tissue at the back of the eye, before the visual information is sent to the brain to be processed. Irregularly shaped corneas don't focus light properly, resulting in impaired vision. While LASIK can correct this irregularity, it can have some potential side effects like eye pain and irritation. More rarely, incisions on the eyes made by lasers can compromise the organ's structural integrity.

To find another possible method to reshape the cornea without lasers or incisions, Michael Hill, a chemist at Occidental College in Los Angeles, and Dr. Brian Wong, a surgeon at UC Irvine School of Medicine, began experimenting with a process called electromechanical reshaping (EMR) to mold tissues in the body. This technique previously enabled the researchers to reshape rabbit ears and alter scars on pigs' skin, approaches that they plan to develop for eventual use in human patients.

Related: How do screens damage your eyes?

EMR uses electricity to alter tissues. Many collagen-containing tissues in the body, including the cornea, are held in place by oppositely charged components attracted to each other like magnets. These tissues also contain water, so zapping the tissues with electricity ultimately lowers their pH, making them more acidic. With the pH altered, the attraction between opposite charged components is unlocked, loosening up the tissue and making it moldable. When scientists then cut the electricity and restore the tissue's original pH, it locks back into the new shape.

Hill and Wong wondered whether EMR could be used to reshape the cornea. To see, they ran tests with rabbit eyes in lab dishes. They created a platinum contact lens template to imitate the corrected shape of a cornea, placed it over a rabbit eyeball in saline solution, and sent an electric current through the platinum lens. Within about a minute, the rabbit eyeball's cornea molded around the contact lens; the whole process took about the same time as LASIK surgery.

The researchers tested this method on 12 rabbit eyeballs, 10 of which were treated as if they had myopia, or nearsightedness. The treatment successfully reshaped the cornea in a way that would better focus light on the retina, and the cells in the eyeballs were not damaged in the process.

The method might also be able to reverse cloudiness in the cornea, Hill and Wong told Live Science, which is currently only treatable through a corneal transplant. That's something they're still experimenting with, but in theory, tweaking the pH of the cornea could also help counter the cloudiness, they think.

Although Hill and Wong are hopeful about the promise of EMR eye treatments, this procedure is in very early stages, they said. The next steps are studies in living animals, and more specific tests to assess which specific vision issues this process can correct, like near- and farsightedness and astigmatism.

"Like any other medical technology it's a process, and you have to go through a fair amount of testing," Wong told Live Science. This includes testing more with animal tissues and with live animals, resolving any issues that arise, and eventually moving on to various phases of clinical trials in humans.

These early preclinical tests of the method are promising in that they show the procedure is safe for eye cells and that the cornea remains clear after EMR alteration, Maria Walker, an optometrist at the University of Houston, told Live Science. But further testing would need to investigate possible longer-term effects. "It might be safe and the cornea might be clear, but then what happens in a month?" said Walker.

Some issues with laser eye surgery, although rare, come from heat transfer to the cornea, which EMR techniques would avoid, Walker noted. "My impression is cautiously optimistic," she said. "I think it's promising."

If the method is proven to be successful and safe in humans, it could someday offer an alternative or complement to LASIK that's possibly reversible — since it's not actually removing any tissue, just rearranging it — and cheaper, the researchers suggest.

"You can't treat every single problem of the cornea with LASIK, there are areas where it simply doesn't have application," said Wong. There are certain patients who aren't good candidates for LASIK. "So I think there are areas where this would have value complementing LASIK."

The cost of EMR equipment would also be cheaper than laser equipment, said Wong, which could potentially make it accessible to more patients looking to correct their vision.

This article is for informational purposes only and is not meant to offer medical advice.

The symptoms: The woman visited an outpatient psychiatric clinic and told the doctors that when she looked at people's faces, she saw them transform into the faces of dragons. She also saw dragon-like faces appear in front of her spontaneously, even when no people were present. These hallucinations were disturbing and affected her ability to interact with people.

The patient reported that human faces that seemed normal at first "turned black, grew long, pointy ears and a protruding snout, and displayed a reptiloid skin and huge eyes in bright yellow, green, blue, or red," doctors wrote in a report of her case. She added that she had experienced these hallucinations since childhood.

What happened next: Doctors at the clinic conducted blood tests, used a brain-scanning technique called an electroencephalogram (EEG), and did a neurological examination. All of the results were normal. However, an MRI of the patient's brain showed several lesions near the lentiform nucleus. Damage to this part of the brain has been linked to cognitive impairments, such as issues with attention and memory, particularly associated with schizophrenia.

These lesions — which appeared in the insulated wiring of the brain, called white matter — may have been caused by ruptures in small blood vessels in the brain. But the damage was not recent, according to the report.

Although the EEG did not reveal any abnormalities, the doctors suspected that the patient's visual hallucinations were caused by atypical electrical activity in parts of the brain that process colors and faces — specifically, the ventral occipitotemporal cortex. This region, located in the back of the brain, is involved in regulating object recognition. The lesions revealed by the MRI may have triggered this electrical activity, the doctors theorized, and they may have been present since birth, perhaps caused by temporary oxygen deprivation shortly before or after delivery.

The diagnosis: The physicians determined that the woman had a form of prosopometamorphopsia (PMO). This uncommon condition affects how a person perceives human faces, making facial features appear dramatically distorted. Features may seem enlarged or shrunken; they may sag, stretch sideways or drift out of position.

For people with hemi-prosopometamorphopsia, or hemi-PMO, just one side of the observed face is affected. In full-face prosopometamorphopsia, or full-face PMO, distortion warps the entire face a person sees. The condition is associated with changes to brain structure and with disorders that affect brain function, such as epilepsy, migraine and stroke.

The treatment: The doctors prescribed the patient daily doses of valproic acid, an anticonvulsant that prevents seizures and also alleviates migraines and symptoms of bipolar disorder. The treatment brought the woman's visual hallucinations under control.

However, she then began experiencing hallucinations of banging sounds in her sleep. The doctors switched her to a daily regimen of rivastigmine, a drug that is commonly used to treat symptoms of dementia caused by Alzheimer's disease or Parkinson's disease. The drug made these auditory hallucinations less frequent and reduced her visual symptoms to a manageable level. After three years of this treatment, the woman reported that her work situation had stabilized and her social relationships had improved.

What makes the case unique: Prosopometamorphopsia is exceptionally rare, with only 81 cases described in the medical literature over the past 100 years, according to a 2021 review.

For most people who experience this condition, its distorting effect on human faces lasts just a few days or weeks. PMO-triggered distortions have been known to make people's faces appear "demonic" — but in the woman's case, it's unclear exactly what caused her highly specific perception of reptilian dragons.

This article is for informational purposes only and is not meant to offer medical advice.

The Maryland patient had returned to the U.S. after traveling to El Salvador, HHS spokesperson Andrew G. Nixon told Reuters in an email, and the Centers for Disease Control and Prevention (CDC) confirmed the infection with the New World screwworm (Cochliomyia hominivorax) via images of the larvae on Aug. 4, according to Axios.

"This is the first human case of travel-associated New World screwworm myiasis (parasitic infestation of fly larvae) from an outbreak-affected country identified in the United States," Nixon said in an emailed statement to Axios. However, "the risk to public health in the United States from this introduction is very low," he added.

C. hominivorax is a species of parasitic fly that lays eggs inside the open wounds, eyes, noses or mouths of warm-blooded animals. Female screwworm flies can lay up to 300 eggs at a time. When the eggs hatch, screwworm larvae use their sharp mouths to burrow into the host's flesh, which causes a painful infestation called myiasis.

New World screwworms primarily affect cattle and other livestock, but they can also cause infestations in humans. An infestation can be fatal if left untreated, but a doctor can usually treat myiasis by removing the larvae. People who work with livestock, have weakened immune systems, open wounds, or who sleep outdoors are most at risk for developing an infection, according to the CDC. But because screwworm is an insect and not a virus, it’s not contagious, Max Scott, a professor of entomology and plant pathology at North Carolina State University, told NPR.

The New World screwworm is endemic to South America and the Caribbean, and it isn't typically found in the U.S., according to the CDC. No cases of screwworm infestation have been found in U.S. animals so far. In the 1960s, the U.S. eradicated New World screwworms within the country by releasing male sterile screwworm flies into infested areas. The sterile flies mated with wild female flies, but the eggs didn't hatch, which caused screwworm populations to decline.

Since 2023, screwworm populations have been increasing in Central America and slowly spreading northward. In November 2024, a screwworm infestation in Mexico prompted the U.S. to temporarily pause livestock imports at the southern border. Imports resumed in January, only to halt again in May. Ports are now reopening in stages, according to the U.S. Department of Agriculture, and a new sterile fly dispersal facility is being constructed in southern Texas.

Inside cells, DNA gets twisted, copied, and pulled apart. The twists can influence how genes function, affecting which are switched on and when. Studying how DNA responds to stress can help scientists better understand how genes are controlled, how the molecule is organized, and how problems with these processes might contribute to disease.

For years, researchers have been using nanopores — tiny holes just wide enough for a single DNA strand to slip through — to read DNA sequences quickly and inexpensively. These systems work by measuring the electrical current flowing through the nanopore. When a DNA molecule passes through, it disrupts that current in a distinct way that corresponds with each of the four "letters" that make up DNA's code: A, T, C and G.

Unexpected slowdowns or spikes in this signal were often interpreted as knots in DNA. But now, a new study published Aug. 12 in the journal Physics Review X finds that these signal changes can also signify plectonemes, which are natural coils that form when DNA twists under stress.

"Knots and plectonemes can look very similar in nanopore signals," lead study author Ulrich Keyser, a physicist at the University of Cambridge's Cavendish Laboratory, told Live Science. "But they come from very different physical mechanisms. Knots are like tight tangles; plectonemes are more like coiled springs, formed by torque."

To study these coils, the researchers passed a DNA strand through a cone-shaped nanopore in a salty solution with a high pH. The solution helped to create an electroosmotic flow, meaning the DNA began to spin as it entered the pore. The motion generated a strong enough twisting force, or torque, that it coiled the DNA, Keyser explained.

Related: DNA has an expiration date. But proteins are revealing secrets about our ancient ancestors we never thought possible.

Keyser and his team also applied an electrical voltage across the nanopore to help drive the DNA through and measure changes in electrical current.

"In these kinds of nanoscale systems, everything is very high friction, so the DNA moves almost like it's swimming through honey," Keyser said. "It's a very viscous environment, so relatively high forces push the DNA in this corkscrew motion."

The researchers analyzed thousands of these events. While some knots still appeared in the experiment, they tended to be smaller — approximately 140 nanometers across — whereas plectonemes were about 2,100 nanometers across. As the voltage applied to the system was increased, plectonemes became more common due to a stronger torque.

To further test how twisting affects DNA behavior, the researchers introduced small breaks, called nicks, into one strand of DNA's double helix. These nicks enabled the DNA to rotate more easily and release built-up tension, which, in turn, caused fewer plectonemes to form. This confirmed that torsional stress is a key driver of these structures' formation.

"When we controlled the molecule's ability to rotate, we could change how often plectonemes appeared," Keyser said.

Although nanopores are very different from living cells, these kinds of plectonemes may also form during processes like DNA transcription and replication. Transcription describes when DNA's code gets copied down by another molecule, called RNA, and shipped off into the cell. Replication describes when the DNA molecule is replicated in full, which happens when a cell divides, for instance.

"I believe that the torsion in the molecules can actually give rise to the formation of i-motifs and G-quadruplexes," Keyser told Live Science, giving the names of two specific types of knots seen in DNA. So what they found in their lab study likely has implications for living cells, he explained.

Keyser and his team have been investigating how plectonemes and other DNA structures form during natural processes, such as transcription. In earlier work, they explored how torsional stress affects DNA replication. Nanopores give scientists a way to not only read DNA but also to watch how it behaves, this study emphasizes.

"Just the fact that the DNA molecule can squeeze through the pore, where its stiffness is supposed to be much larger than the pore diameter, is quite amazing," Slaven Garaj, a physicist at the National University of Singapore who was not part of the study, told Live Science. "It's 10, 50, even 100 times stiffer than the pore size. Still, it bends and passes through."

Garaj was excited about the findings. In the future, "we might be able to separate nanopore-induced torsion from torsion that was already in the DNA before. That could let us explore natural supercoiling in new ways," he added. This would be important for understanding how coils and knots control gene activity.

Similar experiments involving brain-dead patients have previously taken place in the U.S., but they involved different pig organs, such as kidneys and hearts, and a previous experiment in China involved a pig liver. These experiments have paved the way to transplants of pig organs into living human patients, although only a handful of those procedures have been performed so far.

The recent experiment, described Monday (Aug. 25) in the journal Nature Medicine, took place in Guangzhou, China, and involved a 39-year-old male who had been declared brain-dead prior to the procedure. The team confirmed that the patient was brain-dead through four different assessments and gained written informed consent from his family to perform the experiment, according to the report.

This is the first time doctors have attempted to transplant a lung from another species into a human — a procedure known as lung xenotransplantation.

"For our team, this accomplishment is a meaningful beginning," study co-author Dr. Jiang Shi, a doctor in the department of organ transplantation at the First Affiliated Hospital of Guangzhou Medical University, told STAT. "Lung xenotransplantation presents unique biological and technical challenges compared to other organs." The aim of the study was to investigate how the human immune system might react to such a transplant, "not to claim clinical readiness today," Shi added. In other words, the technique is not yet ready for prime time in living patients; it's still in preclinical investigation.

Once transplanted, the pig lung "maintained viability and functionality" for nine days, even though it showed signs of rejection as early as 24 hours after the procedure. The experiment ended on Day 9 at the request of the patient's family. From the report, it's unclear how much longer the lung might have lasted had it been left in for longer, but the organ had accrued damage by Day 9.

Related: Can you transplant an organ more than once?

"Nobody would sign up for a nine-day lung transplant," Dr. Adam Griesemer, a senior member of the xenotransplantation team for NYU Langone's Transplant Institute who was not involved in the procedure, told CNN. That said, "I think it is very important to do these studies [in brain-dead people] since you can't assume that the animal models are going to perfectly reflect what happens in human recipients," Griesemer added.

The experiment involved a lung from a pig that had been genetically modified using the gene-editing technology CRISPR; a company called Clonorgan Biotechnology in Chengdu, China, handled the editing. Three of the pig's genes were disabled so that the proteins for which they code wouldn't activate the human immune system; three human genes were also added in an attempt to make the organ more tolerable to a human body.

In May 2024, the transplant team removed the left lung of the pig and transplanted it into the brain-dead patient, who retained his right lung. Immunosuppressive drugs were introduced to the patient's body starting one day before the procedure and were given daily following the operation.

The patient's body didn't show signs of "hyperacute rejection," which would have taken place immediately after the transplantation if it did manifest. Although the lung made it over that initial hump, signs of rejection began to emerge around the 24-hour mark, marked by swelling and inflammation. The immune system generated antibodies against the organ by the third day after the operation, resulting in some damage to the lung.

The researchers suggested that for future attempts at this type of experiment, it might help to block the action of specific immune cells, as well as to suppress certain signaling molecules that ramp up inflammation. The lungs present a huge challenge because, given that they're constantly exposed to air from outside the body, they carry many proteins geared toward immune defense — this paradoxically makes them an easy target for the host immune system to see as "foreign." Additionally, their tissue that exchanges oxygen and carbon dioxide is very delicate, meaning any immune attacks launched against them pack a punch.

Other questions remain about how to improve upon the approach and how well it could work for a living patient. Based on the current study, for instance, it's unclear how well the pig lung could have supported the patient if he was removed from life-support machines, Dr. Richard Pierson, a thoracic transplant surgeon at Massachusetts General Hospital in Boston who was not involved with the recent procedure, told Science News.

"Future studies can refine the approach to lung xenotransplantation and move closer to clinical translation," the study authors concluded. "This study provides crucial insights into the immune, physiological and genetic barriers that must be overcome, and paves the way for further innovations in the field."

Estimates suggest that these key cells, known as inhibitory interneurons, make up some 25% to 50% of the neurons in the adult cortex, the wrinkled tissue that covers the surface of the brain. In fact, the human cortex carries more than double the number of interneurons as the mouse cortex does.

These interneurons relay signals between other brain cells and help keep that signaling in check with a chemical messenger called GABA. As the brain's main "inhibitory" messenger, GABA helps turn down brain activity by making neurons less likely to fire, thus balancing out the "excitatory" signals that amplify brain activity. Various disorders have been tied to problems with interneurons, including epilepsy, autism and schizophrenia.

Now, in a study published Aug. 6 in the journal Nature, researchers have uncovered a force that drives interneurons to multiply in the developing human brain — and they say it may be unique to our species.

"That's why we cannot use traditional animal models," study co-author Diankun Yu, an assistant researcher in pediatrics at the University of California, San Francisco (UCSF), told Live Science. To uncover this mechanism that may unfold only in the human brain, the researchers developed an organoid — a miniature 3D structure, grown from stem cells, that mimics a full-size structure found in the human body.

Prior to the organoid study, research in lab animals suggested a link between the activation of the maternal immune system during pregnancy and a lower number of interneurons in the cortices of their offspring, compared to offspring that didn't experience an immune upset. That kind of activation might occur in response to a viral or bacterial infection, for example. The study authors explored this in previous research with lab mice, in which they pinpointed a key player behind the link: microglia, the brain's resident immune cells.

Related: In a 1st, scientists combine AI with a 'minibrain' to make hybrid computer

In the past five years, scientists have begun to recognize how the immune system and nervous system develop in parallel, study co-author Dr. Xianhua Piao, a physician-scientist who specializes in neonatology and developmental neuroscience at UCSF, told Live Science.

"The microglia really fine-tune and regulate nervous development," she said of the new study's findings. "It really adds a new dimension as to how microglia exert their function."

The team built on previous work from other research groups to develop their organoids, which resembled a key structure in the fetal brain from which many cortical interneurons arise. This structure is temporary, appearing around the eighth week of pregnancy in humans and disappearing about eight months after birth, Piao said. The researchers found a way to incorporate microglia into this model, which hadn't been done before, she added.

The team found that the microglia in their organoids were a key source of insulin-like growth factor 1 (IGF1) in the developing minibrains and that the substance helped to drive the dramatic increase in interneurons seen in early development.

When the team tested what would happen when they turned off IGF1 signaling in various ways, they found that it blocked the rapid increase in interneurons. However, "when we deleted this gene in microglia in the mouse model, we did not see any change," Piao said. That suggests that this chain of events kicked off by microglia-made IGF1 may be unique to humans.

"These findings indicate an evolutionary adaptation of microglial function to support the increased demand for interneurons in the human cortex," the researchers wrote in their report. In short, this finding hints at a feature of human evolution that might help to explain our unique cognitive abilities.

That said, organoids aren't exact replicas of the human brain, so there's a limit to what the 3D models can tell us. "So far the model is good enough for especially the proliferation stage, very early stage" of development, Yu said. But currently, these organoids don't do as well with later stages of brain development, he noted. They also don't capture circuit-level activity in the brain, Piao said, showing only activity within smaller, isolated structures.

Future work could help to further clarify this previously unknown role of immune cells in the brain, she said.

Specs-wise, it is a big step up from the Whoop 4.0. Compared to its predecessor, the Whoop MG is smaller, lighter, and equipped with more features — it can now measure your ECG and blood pressure, for example. This new model also promises longer battery life (two weeks as opposed to just 5 days), improved tracking accuracy and a 60% faster processing speed. Media backlash or not, the Whoop MG has what it takes to dethrone the Whoop 4.0 and claim a spot in our guide to the best fitness trackers.

Whoop MG review

Whoop MG: Design

• Sleek and discreet
• Can be worn anywhere on the body
• Sharp edges at the clasp and bulky sensor

The design is both the strongest and the weakest trait of the Whoop MG band. On the plus side, this wearable is way more functional than fitness watches. It is sleeker and more discreet, and it does not overload your wrist with heavy machinery or distract you mid-workout with a huge, blinking display. In fact, the Whoop MG does not have to be on your wrist at all. You could just as well place it on your ankle or arm, and thanks to its unique Any-Wear Technology, even on your waist or torso (that said, you would first have to invest in the Whoop smart apparel). This design tweak offers some tangible benefits. If you are a swimmer, for example, placing the wearable in your swimsuit rather than on the wrist could help you reduce your drag in the water and thus maximize your performance.

On the other hand, the design of the Whoop MG can be dreadfully impractical on a day-to-day basis. The lack of a screen is an obvious disadvantage here. You can't check your workout stats at a glance or keep up with notifications — every single time you want to view anything, you have to log in to the Whoop app. We found this particularly frustrating while exercising in the gym. Heavy weightlifting involves rapid, short-term changes in heart rate that we typically monitor with a glance at the watch face. With the Whoop MG, however, we always had to keep our phone screen nearby.

The locking mechanism on the strap is another downside. It is not particularly intuitive, so it takes some time to master. Secondly, the buckle that keeps the sensor in place has relatively sharp edges. This can pose a safety risk (especially in certain contact sports), and it can be uncomfortable while sleeping. For example, we tend to snooze with our hand placed underneath our head, where this sharp clasp was pinching our face.

Moreover, the Whoop MG does not feel very female-friendly. The sensor is too wide and bulky for comfortable all-day wear, and it only comes in one color. Sure, you can add some personality to your tracker by swapping its default black straps with some brighter ones, but you will not be spoiled for choice here. We also found the Whoop replacement straps to be unreasonably expensive — the cheapest one costs a whopping $49. You can get a knock-off band from Amazon, but then it is not guaranteed that it will fit.

Then there is the relatively high price of the Whoop MG. The device itself costs $359, which places it on par with some of the more premium Garmin watches, plus it requires a subscription to work properly. The Whoop app costs $199 per year for the basic package, and if you want to have full access to the features on your tracker (the ECG and blood pressure insights, for example), you have to fork out a whopping $359 per year.

Whoop MG: Features

• Detailed analysis of the body's strain and recovery
• ECG and blood pressure measurements
• AI-driven personalized coaching

The Whoop bands have always dazzled with their advanced features, and the MG is no different. This fitness tracker is best suited for serious athletes and data geeks who are laser-focused on maximizing their exercise performance and recovery. For beginners, however, the Whoop MG can be a feature overkill. While most metrics come with sufficient explanations and actionable, easy-to-understand tips, there may simply be too many of them to bring real value to those who have never used a fitness tracker before.

We can't really get into each and every feature of the Whoop MG here (otherwise, this section would be five pages long), so we will try to keep things short and sweet. This wearable is focused on three main metrics — sleep, strain and recovery — all of which are calculated based on its continuous measurements of your heart rate, movement and skin temperature. It also tracks various other stats, including stress levels, calories, steps and VO2max (the maximum amount of oxygen that a person can use during exercise). In addition, the Whoop MG can take on-demand ECG (heart rhythm) readings and estimate your blood pressure (you first need to calibrate the algorithm with a traditional blood pressure cuff).

Every morning, your Whoop MG will ask you to complete your journal. You can choose which activities and symptoms you want to log in, and whether you want them to form part of your "Feel Better Plan". We found this feature to be very useful. For example, it helped us track our hay fever symptoms and associated fatigue levels — not something many fitness trackers can do.

Another feature that scored highly in our books was the menstrual cycle tracker. Of all the fitness wearables we have tested, the Whoop MG proved to be the most detailed and accurate in its predictions in that regard. We particularly liked the little snippets of personalized guidance that accompanied each of our cycle phases. We could only wish more brands took this important aspect of human biology with the same degree of care and understanding.

Then there is the AI-powered coaching. Essentially, it is a chatbox, similar to one we have seen in the Amazfit Zepp app. While we did not use it much ourselves, we appreciate that Whoop MG has a feature that can help its users better understand their health and fitness data. Again, that is not something too common for fitness tracker brands.

Lastly, the Whoop MG comes with its own communities. While you will not be able to directly interact with other users, you can choose which "team" you want to be in (for example, Whoop Yogis or Whoop Women 30-40) and see all the activities its team members logged into their apps. If you have a competitive streak (or simply want to snoop around), this feature will surely be up your street.

Whoop MG: Performance

• Up to two weeks of battery life
• Largely accurate health and fitness tracking
• App connectivity can be patchy

The Whoop MG promises up to two weeks of battery life — and that is indeed true. Our testing unit lasted on average 12 to 13 days, with at least four tracked workouts a week. No complaints here. If anything, we were not too keen on the weirdly-shaped charger. Sliding the sensor into the charging dock takes some strength and manual dexterity, and we think it is just more hassle than it needs to be.

The health and fitness tracking on the Whoop MG is largely accurate, but it differs slightly depending on the metric. For example, we were particularly impressed with the reliability of its sleep and heart rate measurements. During one workout, we wore both the Whoop MG and the more precise Polar H9 chest strap heart rate monitor, and obtained impressively similar results regardless of the exercise intensity. Most fitness trackers we test tend to lose accuracy when the heart rate goes roughly above 140 bpm, but that did not apply to the Whoop MG. The sleep tracking also seemed to be highly precise.

The stress and activity tracking, on the other hand, could use some improvement. The Whoop MG is supposed to automatically detect your workouts, but based on our experiences, it either does not "see" your activities (and therefore logs the elevated heart rates as stressful reactions) or misinterprets them. For example, it once logged our shower as "dancing". Moreover, we found the workout tracking to be quite basic. If you want to track complex stats (stroke rate for indoor rowing, for example), the Whoop MG may not be the best option for you.

Speaking of tracking, the Whoop MG takes quite a few weeks to calibrate. This means that it may not display accurate results straight away. We found that to be particularly pronounced with stress tracking — our measurements were wildly off the mark in the first couple of weeks, but improved markedly afterwards. It is a good sign. The Whoop MG can actively "learn" your body and provide you with more personalized feedback, and that is not something many fitness trackers do.

Our biggest gripe with the Whoop MG was its patchy app connectivity. On most days, it was perfectly fine. On others, it stopped working for no apparent reason. Our testing unit must have disconnected from the app at least a dozen times, each time forcing us to meddle with our Bluetooth settings. On one occasion, we even resorted to resetting the device. True, we have always managed to restore connectivity without losing any data, but we found this flakiness to be quite annoying.

All in all, the Whoop MG is a fabulous health tracker with exceptional battery life, but its performance hiccups are too frequent and disruptive to brush off. If this wearable were cheaper, we probably would not mind as much, but at this price range, the bar is set much higher.

Whoop MG: User reviews

The Whoop MG scores 4 out of 5 stars on Amazon, with two-thirds of users giving it the highest rating. Positive reviews often praise this wearable for its insightful health and fitness tracking, long battery life and good data accuracy.

One happy buyer said, "My Whoop has been a game-changer for my health, performance, and overall lifestyle. I am a trainer and work at a bar, so late nights and early mornings are unavoidable. My Whoop has made a huge difference in how I pay attention to my sleep and recovery. I started with Whoop almost a year ago and loved it. I was super excited about this new band and haven’t been disappointed. The new insights and tools this band provides are amazing, and with the 14-day battery life, I would say this upgrade is completely worth it."

Negative reviews, on the other hand, tended to revolve around its high price tag, skin-irritating straps and poor compatibility with Apple's app ecosystem. Several users also complained about Whoop's customer service.

One user commented, "The moment you try to return, update, or manage your account, WHOOP shows its true face: a company built on confusion, hidden charges, and a broken support system. Customer service is a black hole — canned responses, no resolution, and endless back-and-forth. You’ll waste hours, if not weeks, trying to fix simple issues while they quietly keep charging you."

Should you buy the Whoop MG?

✅ Buy it if: You are serious about elevating your exercise performance and/ or looking for an advanced fitness tracker that you can put anywhere on your body. The Whoop MG is versatile and discreet, but more importantly, it delivers heaps of useful data on your sleep, strain and recovery. A perfect choice for serious athletes and performance geeks.

❌ Do not buy it if: You are on a budget, want to prioritize workout tracking, or frequently engage in contact sports. The Whoop MG does not provide nearly as many exercise stats as other fitness trackers in its price range, and the sharp edges on its clasp may pose a safety risk to those who train in martial arts or team sports like rugby and basketball.

If Whoop MG is not for you

Like the idea of a screenless fitness tracker? Think of a smart ring. The Oura Ring 3 and Ultrahuman Ring AIR, for example, are similar to the Whoop MG in terms of price and functionality, but they are smaller and more elegant. Plus, many smart rings (such as the Ultrahuman Ring AIR or Amazfit Helio) do not require a subscription.

Looking for something cheaper? Consider the Amazfit Balance instead. This subscription-free smartwatch costs less than $200, but it is stylish, comfortable to wear and jam-packed with detailed insights into your sleep, stress and recovery. The downside? It is nowhere near as data-focused as the Whoop MG.

Whoop MG: How we tested

We spent nearly three months testing the Whoop MG band, assessing its design, features, ease of use, tracking performance, connectivity with third-party devices and value for money. We wore it during the day, while sleeping and when doing a range of activities, from swimming in the pool and hiking outdoors to exercising in the gym.

Finally, we assessed the accuracy of our Whoop MG by comparing its heart rate measurements with the data we obtained using a more precise Polar H9 chest-strap heart rate monitor.

"Caffeine withdrawal headaches can be surprisingly intense," Dr. Nolan Pearson, a neurologist and headache specialist at Cedars-Sinai Medical Center in Los Angeles, told Live Science. "It can trigger a migraine-type headache, so it can be pulsing, pounding, throbbing."

But why is caffeine withdrawal so excruciating? Neurologists still aren't entirely sure, but they have a few theories and some tips on how to treat these nasty headaches.

Caffeine withdrawal headaches occur after a person consumes more than 200 milligrams of caffeine — the amount in about two cups of coffee — per day for more than two weeks and then abruptly stops, according to the International Classification of Headache Disorders (ICHD-3). The headaches usually appear within 24 hours without caffeine, and typically go away within one week or when caffeine is consumed again.

Why withdrawal headaches are so painful remains somewhat unclear. Because caffeine affects many parts of the body, experts haven't been able to pin down a single overarching cause. But the pain likely comes, in part, from dilated blood vessels.

Caffeine constricts blood vessels — which is part of the reason why the drug can also, paradoxically, be used to relieve some types of headaches, according to the Mayo Clinic. When caffeine use stops, those blood vessels swell, causing more blood flow and, therefore, pain. But Dr. Brian McGeeney, a neurologist and headache specialist at Boston's Brigham and Women's Hospital, said that's just one contributing cause.

"It's involved, but it's not the whole story," he told Live Science.

Related: Does caffeine help or cause headaches?

Another explanation for caffeine withdrawal headaches has to do with adenosine receptors. The drug blocks adenosine, a building block of RNA, from attaching to receptors scattered across the central nervous system. This causes neurons to fire more quickly and blood vessels to constrict, which, in turn, makes people feel more alert and awake.

When someone stops consuming caffeine, the sudden buildup of adenosine in the body can contribute to withdrawal headaches. This is also why caffeine is commonly used to treat headaches: By blocking adenosine receptors, it prevents blood vessel dilation from the outset. In fact, caffeine can make painkillers like ibuprofen and acetaminophen work more efficiently, according to the Mayo Clinic.

But, as Pearson noted, much of caffeine withdrawal is yet to be explained. "We certainly don't know, but these are all reasons why it might be causing headaches," he said.

Caffeine withdrawal often happens in hospital settings when patients have to quit their coffee habit to undergo a medical procedure. Some studies also show caffeine withdrawal symptoms in people who fast, such as Muslims observing Ramadan.

"When life is interrupted unpredictably, like you end up in the emergency room or get admitted to hospital, you see a lot of caffeine withdrawal," McGeeney said.

Caffeine is usually safe in moderation. But when someone is looking to reduce or eliminate their caffeine intake, experts agree that the best strategy is to cut down gradually. Drink a little less each day, or substitute lower-caffeine alternatives, like tea, to make the transition easier.

"If somebody's using caffeine chronically and they want to cut back, I would do it quite gradually," Pearson said. "So no faster than about 25 to 50 milligrams of caffeine reduced per day — that's a quarter to half a cup of coffee."

If a headache lasts longer than a week, Pearson recommended seeking medical care, as that time frame suggests the headache may be triggered by something other than caffeine withdrawal.

This article is for informational purposes only and is not meant to offer medical advice.

Many outlets — including Newsweek, The Economic Times, and ChosunBiz — named a Chinese outlet, Kuai Ke Zhi, as the story's source. Zhang Qifeng, the developer of the bot intended to carry a pregnancy from conception to birth, reportedly told the outlet that a prototype would be ready as early as 2026 at a price point under 100,000 yuan (around $13,900 USD).

"Some people don't want to get married but still want a 'wife'; some don't want to be pregnant but still want a child," Zhang said, according to Newsweek. "Mature" artificial womb technology just "needs to be implanted in the robot's abdomen so that a real person and the robot can interact to achieve pregnancy," he said, according to ChosunBiz. The nature of that human-robot interaction was not detailed.

Depending on the article, Zhang was cited as the CEO or founder of Kaiwa Technology, a Guangzhou-based company, or as a PhD affiliated with Singapore's Nanyang Technological University (NTU). Finding no online evidence of Kaiwa Technology, Live Science contacted NTU about their purported affiliation with Zhang Qifeng.

"We would like to inform you that no one by the name of 'Zhang Qifeng' graduated from NTU with a PhD," an NTU spokesperson told Live Science via email. "Our checks also showed no such 'gestation robot' research has been conducted at NTU."

As you may have suspected — and as Snopes has also confirmed — the pregnancy robot isn't real. But the viral story raised questions about the potential of artificial-womb technology. Would it be possible to build a pregnancy robot? Or is the concept pure science fiction? Live Science spoke with experts about the idea, discussing whether it would technically be possible and whether anyone should even try.

"Should we do it? My answer would be categorically 'no,'" said Dr. Harvey Kliman, director of the Reproductive and Placental Research Unit at Yale University School of Medicine. "That being said, intellectually, I think it's interesting to think about the challenges because it helps us actually reflect about what is the beauty and miracle of a normal pregnancy."

Related: If 'pregnancy robots' were real, would you use one?

Artificial wombs?

The pregnancy robot is fake, but scientists have been developing artificial wombs. At Children's Hospital of Philadelphia (CHOP), scientists are developing a womb-like device called the "extra-uterine environment for newborn development," or EXTEND. The eventual hope is to support babies who are born extremely premature, between 23 and 28 weeks of gestation.

Recent advances have decreased the death rate associated with preterm birth, but health issues, including chronic lung disease and neurodevelopmental problems, remain a big concern for babies born that early. To decrease these risks, CHOP researchers aim to create a uterus-like environment that babies can be placed in after delivery to help them over the 28-week mark.

The device includes a bag full of amniotic fluid, which is made in the lab and contains key nutrients and growth factors. The umbilical cord is attached to an "external oxygenator" that partly stands in for the placenta, facilitating an exchange of oxygen and carbon dioxide. Within the device, a baby would be insulated from changes in temperature, pressure and light, as well as from exposure to germs.

EXTEND has so far been tested with lambs. In a 2017 paper, the team showed that fetal lambs could be supported in the device for a month and that their development continued much as it would have in the womb. In a 2024 paper, they collaborated with Duke University researchers to see how EXTEND impacted gene activity in the brain. The device helped preserve gene activity in premature lambs' brains so that it resembled that of lambs that remained in the womb for much longer.

Meanwhile, some researchers are working on artificial placentas that would fulfill the same purpose as EXTEND, supporting premature babies. These devices have also been tested in lambs but are farther out from human trials than EXTEND is.

The EXTEND team aims to move into human trials soon, though there are questions about when and how it would be ethical to test the device, given many premature babies have a fighting chance with existing technologies.

"In a human setting, a couple weeks is not enough," said Dr. Lusine Aghajanova, a fertility specialist and clinical associate professor of obstetrics and gynecology at Stanford Medicine, in reference to the length of the tests done so far in lambs. "What that study showed is that it's a concept that can be possible, but it's more complicated than we think," she told Live Science.

Throughout their efforts, the EXTEND developers have stressed that the device is intended as a bridge for premature babies moving from the womb into the world; it is not intended to be used to push fetal viability earlier than 23 weeks. Of course, there's a big difference between keeping an ailing baby alive and gestating a baby from conception, as the fake Kaiwa pregnancy robot was supposed to do.

Related: Should we rethink our legal definition of a human embryo?

Like a 'tomato plant suspended in water'

Presumably, a gestation robot might need to deal with a particularly tricky part of pregnancy: implantation.

In an unassisted pregnancy, an egg travels through a fallopian tube, where it is typically fertilized before moving into the uterus and implanting in the uterine wall. In fertility treatments, such as in vitro fertilization (IVF), a fertilized egg is placed into the uterus, where ideally, it then implants itself. That aspect of the treatment is not directly orchestrated by doctors.

In a robotic incubator, though, implantation may not be a critical step, Kliman said. "I'm thinking about hydroponics," he said. "Think of it as a tomato plant suspended in this bucket of water, right?"

Similar to the EXTEND studies with lambs, in theory, a human embryo could be suspended in fluid rather than embedded in something akin to the uterine wall, he said. The real challenge would be ensuring that the embryo remains suspended, so it can grow unimpeded, and that it's supplied with adequate nutrients and factors to grow. The placenta "doesn't actually have to attach to anything or burrow into anything" in that kind of setup, Kliman said.

Aghajanova, on the other hand, thinks recreating implantation would be key. "Implantation is absolutely important," she said. "It's the seed and the soil," referencing the embryo and the uterine lining. Abnormalities in the uterine lining can undermine both fetal growth and placental development, she argued, so some stand-in for the tissue would likely be necessary in a pregnancy robot.

Even if the implantation issue was addressed, delivering the right nutrients to the fetus at the right time could still be tricky.

Early in pregnancy — roughly up to the eighth week or so — glands in the uterine lining produce a nutritious "milk" for the developing embryo and placenta. At that point, blood flow from mother to womb is not fully established, in part, because the maternal blood is too oxygenated, Kliman said. "That high-oxygen state causes too many free radicals and would destroy the DNA of the dividing embryo," he said, so instead, the early womb maintains a low-oxygen state.

In a robot pregnancy, you'd need to carefully recreate that transition from low- to high-oxygen, as well as maintain the womb-like environment and keep it flush with nutrients for months on end. Maternal metabolism shifts dramatically in pregnancy, Aghajanova said, so it would be difficult to know what dose of oxygen is needed at any given stage of development.

"That's mind boggling to me. I'm just trying to think of any system that would work flawlessly for nine months and not get infected," meaning exposed to germs that could derail the whole process, Kliman said. "We're talking extreme challenges of just the machinery, the reliability, the nutrients, the getting rid of the waste — and again, I think the biggest problem, to be honest with you, would be infection."

While those aspects of an artificial womb would be complex, it might be simpler than human reproduction in other respects, Kliman mused. In human pregnancy, the embryo and placenta must be protected from the maternal immune system, lest they be targeted as foreign invaders. Additionally the uterus undergoes changes to create a suitable environment for the embryo, and the placenta releases hormones that prep the mammary glands to make milk. These factors would be irrelevant in a machine, he said.

There are questions about how the fetal immune system might develop differently in a robot. In a human pregnancy, antibodies pass from maternal blood to the fetus via the umbilical cord. That's why a variety of vaccines are given in late pregnancy: The vaccines stimulate maternal antibody production, those antibodies pass to the fetus, and newborns enter the world with some protection against dangerous infections. And additional, non-vaccine-induced antibodies also cross over.

Given robots lack immune systems, developers of a pregnancy robot might need to figure out how to replicate this process, perhaps with lab-made antibodies or with donated blood.

"I don't think that would be that hard," Kliman said. Some of those antibodies could be supplied after birth via breastmilk or through formula containing lab-made antibodies, he suggested. And you might take extra precautions to keep the baby from being exposed to too many germs too soon, if you knew that might be an issue, he added.

In the womb, the maternal immune system must avoid attacking the growing fetus while also protecting it from pathogens, Aghajanova said. The former issue might not be relevant in a robotic pregnancy, but that latter protection would still be necessary, she said.

Related: 'We know what to do; we just have to implement it.': Pregnancy is deadlier in the US than in other wealthy countries. But we could fix that.

Unanswered questions

An additional factor to consider might be the vaginal microbiome, which contains bacteria, fungi and other microorganisms that studies suggest impact the health of the developing fetus. Figuring out how and what to deliver into the robot to mimic this complex microbial community could be tricky, as we don't fully understand which species are helpful to fetal development.

With the loss of a microbiome would likely come the addition of plastic components within the robot itself, Aghajanova added. It's unclear how all that plastic could sway early development, but it likely wouldn't be great, she suggested.

Other quandaries cloud the notion of a pregnancy robot: How would the eggs and sperm be sourced? Whose gametes would be used to test and optimize the device, proving it could lead to a live birth? Where could such research be conducted, legally? Would fertilization occur inside the bot itself, or via a lab procedure akin to IVF? Who is tasked with maintaining and monitoring the bot's functions throughout the "pregnancy"? What would the birthing process look like for a robot, and would engineers be needed in the delivery room? Are there yet-unknown aspects of human pregnancy that a baby grown in a machine would miss out on?

In our current reality, many of these questions remain unanswerable — but they would certainly make a compelling premise for a sci-fi novel.

"It's good science fiction, but in a word, it doesn't exist yet," Aghajanova said. And "we are not that desperate [for such technology], especially in the U.S." In the United States, patients have access to fertility treatments, donor eggs and surrogates, she said.

For Kliman's part, he said that his main takeaway from this thought experiment is simply "what a miracle a pregnancy is."

"We're just little feeble beings trying to conceive of some way to do this artificially, and look at what nature has done," he said. "And it happens four million times a year in our country; we get a normal delivery. So that's the miracle."

This article is for informational purposes only and is not meant to offer medical advice.

The robot and the related story were — as you might have guessed — pure fiction. But the viral tale nonetheless raised questions about whether designing such a robot could be possible with today's technology, and what ethical quandaries that possibility might raise, in turn.

If a "pregnancy robot" existed, would you consider using one? Take our poll below, and let us know what you think of this sci-fi-sounding idea in the comments below. If you chose "maybe," what would sway your decision?

Related: 'Pregnancy robot from China' is fake, but is the technology behind it possible?

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With her son in her arms, the worst should have been behind her. But within moments, her doctor realized her placenta was stuck to her uterine wall. Hospital staff gathered around her, trying to remove the placenta manually — "a horribly painful experience," Albright, 32, said. She wouldn't stop bleeding.

Mere minutes after giving birth, Albright passed out from blood loss. What she didn't hear was her care team calling for a rapid response, which is an alert in labor-and-delivery units that brings an emergency team of doctors and nurses rushing to the room. This team saved Albright's life with 4 pints of blood (she would later need 2 more) and whisked her to emergency surgery to remove the retained placenta.

This harrowing experience was followed by a traumatic few days in the intensive care unit (ICU) and separation from her newborn. It was compounded by weeks in the neonatal ICU for the new baby, who contracted a rare bacterial infection after birth. But Albright and her husband, Jeffrey Albright, credit their care team with saving both mom and child.

"This could have been so much worse," Jeffrey Albright, 32, told Live Science. "In any way you can think of it, it could have been worse."

For too many families, it is worse. A higher percentage of people die in pregnancy, childbirth or the postpartum period in the U.S. than in comparable wealthy countries. It's a problem of health disparities, access to health care, and how individual hospitals handle emergencies — and the problems could deepen with recent policy decisions in the U.S., experts say.

Despite the bleak numbers, there is hope. Evidence suggests that most of these deaths are preventable and that some relatively straightforward interventions could slash the maternal death rate. Those measures include better prenatal monitoring to prevent emergencies in the first place, as well as more training for hospital personnel to react when emergencies do happen.

"We know what to do," said Jeanne Conry, past president of the American College of Obstetricians and Gynecologists (ACOG) and the International Federation of Gynecology and Obstetrics. "We just have to implement it."

Causes of maternal death

The Centers for Disease Control and Prevention (CDC) defines maternal mortality as the death of a patient during pregnancy or up to 42 days after delivery from any cause related to or aggravated by the pregnancy or pregnancy care. For example, someone who dies in a car wreck during pregnancy wouldn't be counted, but someone with a preexisting heart condition whose condition worsened due to pregnancy would be.

Although maternal death is rare in the U.S., the rate is higher than in other wealthy nations. Provisional CDC data suggest that in 2024, there were 19 maternal deaths for every 100,000 live births, compared with 8.4 per 100,000 in Canada, 8.8 per 100,000 in South Korea, 5.5 per 100,000 in the U.K. and zero in Norway, according to The Commonwealth Fund, a health policy foundation.

The U.S. has long been an outlier among its wealthy peers in maternal mortality, even though the country spends about twice as much per person on health care as other large, wealthy nations do, according to the Peterson Center on Healthcare and the health policy organization KFF, a health policy research organization.

"We rank very poorly on the world stage," said Dr. Monique Rainford, an assistant professor of obstetrics, gynecology and reproductive sciences at the Yale School of Medicine and the CEO and co-founder of Enrich Health, a startup that aims to provide evidence-based prenatal care.

According to The Commonwealth Fund, about half of U.S. maternal deaths happen the day after birth, and about a third occur during pregnancy. During pregnancy, one-third of the deaths are due to stroke and heart conditions, according to the March of Dimes, while emergencies such as hemorrhage cause the most deaths during labor and delivery. Bleeding, high blood pressure (including pregnancy-induced conditions such as preeclampsia, a life-threatening persistent rise in blood pressure that can develop during pregnancy or up to six weeks postpartum), infection and cardiomyopathy (a weakening of the heart muscle) cause the most deaths after delivery.

"What's coming out of our research is that cardiovascular disease is really increasing," Conry told Live Science.

While the U.S. has high rates of certain conditions that increase the risk of complications during pregnancy, birth and the postpartum period — such as obesity — other countries with high rates of these risk factors have much lower rates of death than the U.S.

Maternity deserts

One factor in the U.S.' comparatively poor outcomes is that many women live in "maternity deserts" — areas where there is no nearby hospital that offers maternity services or neonatal specialists. Thirty-five percent of counties in the United States are maternity care deserts, according to the March of Dimes.

As of 2022, 52% of rural hospitals did not offer obstetric care, and the problem has worsened since then. According to 2024 research in the journal JAMA, 238 rural hospitals stopped offering obstetrics between 2010 and 2022, and only 26 rural hospitals added obstetrics to their offerings in that time period. (During the same period, 299 urban hospitals lost obstetrics, but 112 added in new offerings.)

In addition, a 2021 study of New Jersey maternity hospital closures found that women had a higher rate of maternal morbidity rate — a measure of serious and life-threatening complications around pregnancy and childbirth — if they gave birth after an obstetrical unit closed in a nearby hospital.

Lack of maternity care is a big problem in rural areas, but it's not exclusively a rural one. Around 35% of urban hospitals lack obstetric care. In addition, other health care access problems can make it difficult for women to get to prenatal appointments where problems can be spotted and managed early on.

Even in dense Chicago, "if your Medicaid provider is not in network, you're a lot of times forced to use public transport in horrible weather, often with other children, to get preventative care," said Star August Ali, a certified professional midwife and the executive director and founder of the Black Midwifery Collective in Chicago, which aims to train and support Black midwives.

Looming cuts

The Medicaid cuts in the "Big Beautiful Bill Act" signed into law in July could spell deep trouble for maternal mortality. The cuts are expected to hit rural hospitals hard, according to KFF, with the likely closure of 144 rural labor and delivery wards.

And about 41% of U.S. births are covered through Medicaid. While it's not clear how the cuts will affect enrollment during pregnancy, without that coverage, people may not have access to treatments and monitoring that could head off some life-threatening emergencies.

The impact of these policies is not equal. Medicaid covers about 28% of births to white mothers, 64% of births to Black mothers, and 67% of births to American Indian or Alaska Native moms. Younger women are also more likely to be covered by Medicaid than by private insurance, with almost 79% of births to moms under age 20 being covered by the government program.

If fewer pregnant women are covered, "we're going to see a huge uptick of emergency room utilization, a huge decrease in preventative care and early detection," during pregnancy, Ali told Live Science.

Racial disparities

The same groups that may lose the most coverage under the Medicaid cuts are also those that are at higher risk of poor outcomes for mom and baby. Black and Native American women are two to three times more likely than white women to die during pregnancy, childbirth and the postpartum period, according to KFF.

Some of this disparity has to do with access to care and poorer quality of care for people of color. A 2025 study of over 3,000 hospitals showed sparser staffing and worse mortality outcomes in hospitals that served predominantly Black patients compared with hospitals with lower percentages of Black patients. And the 2021 study on maternity unit closures also found that severe maternal morbidity was worse in hospitals that served many Black patients.

Research also suggests that American Indian and Alaska Native patients face serious gaps in their health care coverage, which could prevent them from accessing lifesaving preventive care.

Racial bias by health care providers may play a role as well. A 2017 review of studies on doctor-patient communication found that Black patients experienced "poorer communication quality, information-giving, patient participation, and participatory decision-making" compared with white patients. This could lead to a lack of trust between doctor and patient that affects clinical decision-making, the study researchers wrote. For example, the doctor may view the patient as less engaged and fail to give them important recommendations about how to care for their health.

Preventable deaths

Despite big-picture problems with the healthcare system, the data suggest that there are opportunities to prevent a large number of maternal deaths.

A 2024 study in the American Journal of Obstetrics and Gynecology looked at deaths across 42 states and found that over 90% of deaths from preeclampsia and eclampsia in the U.S. could have been prevented. So could more than 80% of deaths from hemorrhage and cardiovascular conditions and about 70% of deaths from infection. Harder to prevent are deaths from stroke or amniotic fluid embolism, an emergency in which amniotic fluid enters the maternal bloodstream, but even then, 40% of deaths were found to be preventable.

The fraction of deaths that could have been prevented with immediate improvements in medical care varied dramatically among states, from 45% to 100%, the study found.

"The number one finding is this variability," said study author Dr. Andreea Creanga, a public health researcher at the Johns Hopkins Bloomberg School of Public Health.

That variability is actually a cause for hope, experts say, because it suggests there are clear measures that states, hospitals and providers can implement to reduce maternal mortality.

Learning from each death

The first step in preventing these deaths is to study each death in detail, Rainford said.

States that have studied these deaths and used those lessons to make concerted efforts to reduce maternal mortality have seen success. California's long-running Maternal Quality Care Collaborative, for example, prompted a dramatic decline in maternal mortality in the decade after it was started in 2006, putting the state almost on a par with Canada.

The collaborative helps to investigate the causes of individual deaths, looking for preventable factors. "It's transformed things," Conry said.

But current policies and politics may be hindering efforts to learn from past experiences. After the investigative news organization ProPublica reported a series of preventable maternal deaths in Texas and Georgia likely caused by hospitals delaying care out of fear that doctors would be prosecuted under the states' strict abortion laws, Georgia abruptly fired every member of its committee on maternal deaths. The state will not disclose who is now on the committee. The board in Idaho, which also has a strict abortion ban, was dissolved by state lawmakers in 2023 before being reestablished in 2024, leading to gaps in analysis and methodology changes. Texas' committee skipped analyzing deaths in 2022 and 2023, the two years after the Supreme Court overturned Roe v. Wade and enabled the state to enact laws restricting nearly all abortions.

The lack of transparency stemming from abortion politics is a barrier to reducing maternal mortality.

Standardizing care

Creating and implementing standards of care is another way to lower death rates. For instance, after the California Maternal Quality Care Collaborative analyzed maternal deaths in detail, they found a clear pattern: Too many women were dying of postpartum hemorrhage, one of the most common causes of maternal mortality.

So they provided hospitals tool kits to handle emergency scenarios, including standardized drills, training, and instructions to stock a "crash cart" of supplies to handle postpartum hemorrhage.

The same concept of standardized care could be extended to other conditions beyond hemorrhage, Conry said. For instance, the Collaborative will soon release guidance on better recognizing sepsis, a type of life-threatening infection that can occur during or after childbirth.

There is also a need to improve monitoring before labor and delivery. Over time, the immediate causes of death have been shifting from rapidly-developing emergency situations, such as hemorrhage, toward chronic conditions, such as cardiovascular disease, Creanga said.

This underscores the importance of people receiving regular care through pregnancy and for increased monitoring of high-risk individuals. For example, Johns Hopkins has launched an initiative called The Maryland Maternal Health Innovation Program (MDMOM) that includes at-home, telehealth-supported blood-pressure monitoring for pregnant patients with high blood pressure. That could help catch patients whose health is deteriorating, before an emergency happens. (The Preeclampsia Foundation offers a similar program nationwide.)

Creanga and her colleagues are also working to improve education for health care professionals and community groups around warning signs for high-risk pregnancy. The goal is to get tools into the hands of patients and their families, Creanga said, and to move the U.S. into the company of countries like Norway, where maternal death is vanishingly rare.

"Maternal mortality is a marker of the health of your country," she said. "It's maybe the most important marker."

In non-medically assisted pregnancy, an egg travels from the ovary to the uterus via the fallopian tubes, also called uterine tubes. Tubal ligation prevents this movement by permanently blocking, clipping or removing the tubes, thus keeping the egg from becoming fertilized. The removal of the tubes, called a salpingectomy, is a type of tubal ligation.

The procedure is extremely effective, with a 99% free-from-pregnancy rate. That number rises to 100% for surgeries that use large incisions to access the tubes, rather than minimally invasive medical tools that can navigate the body through small incisions.

"It's a great option for family planning that does, unfortunately, involve a surgical procedure," Dr. Andrew Rubenstein, director of General Obstetrics and Gynecology at NYU Langone Health, told Live Science.

Side effects are minimal, but can include shoulder pain, bloating, abdominal cramping, nausea and dizziness, according to Cleveland Clinic. The shoulder pain is related to gas used to temporarily inflate the abdomen during some tubal ligation procedures; that gas can linger and irritate the neck, shoulders and chest for up to a couple days after surgery.

Tubal ligation can be performed whether or not the patient has had a pregnancy previously, Rubenstein explained.

Related: Tube-tying surgeries and vasectomies skyrocketed post-Roe

Regardless of when a person gets their tubes tied, extensive consultation between the patient and the physician is required beforehand. The patient's partner may also be included in the consultation, if applicable.

"It is shared decision making amongst the team members," Rubenstein said, describing the process of deciding what form of birth control is the best approach for each individual patient. "It's not a single episode event and then surgery is scheduled. It does require some doctor-patient relationship."

How does the surgery work?

There are four main methods for completing a tubal ligation, each using a different technique to block the travel of an egg. Doctors may remove both tubes completely — which is called a bilateral salpingectomy, or "bisalp" for short — or partition the tubes by cauterizing, clipping or folding them.

(Unilateral salpingectomies, which remove only one tube, are not a sterilizing procedure but can be used to treat conditions like ectopic pregnancy.)

The method a physician chooses, and whether they agree to carry out the procedure at all, in part depends on a patient's clinical history, Rubenstein said. Doctors will consider factors like age, past surgical procedures and body mass index to see what's feasible for a given patient.

The procedure is often completed through two small incisions, one just below the navel and the other on the lower abdomen above the pelvis. Using laparoscopic tools — a small camera and accompanying instruments that allow the surgeon to see within the body — the physician can complete the permanent operation.

Sometimes a tubal ligation is performed as a preventative treatment to decrease a patient's chances of contracting ovarian cancer. Evidence suggests that ovarian cancers often arise in the fallopian tubes, and that removing the tubes can cut the risk.

"It doesn't eliminate it, but it definitely reduces that risk for patients," Rubenstein said. It's currently unclear by how much tubal ligation lowers the odds of developing ovarian cancer, but some research suggests it decreases by 24% to 42%.

Anyone with fallopian tubes who is uninterested in getting pregnant in the future and already plans to undergo pelvic surgery should consider taking this preventative measure simultaneously, the Ovarian Cancer Research Alliance and the Society of Gynecologic Oncology suggest.

Rubenstein warned that not all operating rooms will perform tubal ligations. "Certain organizations will not allow you to do tubal ligation in their facilities based on religious beliefs, so they have to be done then in a nondenominational facility," he said.

Is it permanent?

Like any operation, tubal ligation can fail — in this context, failure means the patient becomes pregnant after the surgery.

"It's extremely rare," Rubenstein said, but it can happen and is more likely to occur for younger patients. Within the first year after the procedure, the failure rate is estimated to be 0.1 to 0.8% across all patients.

Some providers won't perform the procedure on someone younger than 30, Rubenstein said, on the basis that the patient might later come to regret it. One 2022 study that surveyed about 1,500 patients found that 12.6% of people who underwent sterilization at ages 21 to 30 and 6.7% of those who underwent sterilization when they were older than 30 regretted their choice. Notably, the majority of the patients — 92% — were in the over-30 group, so the sample of under-30s was somewhat small.

To place the 2022 study in greater context, the average regret rate reported is similar to that for knee replacement surgery, at around 10%.

Rubenstein thinks it is important to emphasize that tubal ligation is a permanent surgery. "People have a misconception that tying your tubes is similar to tying your shoelaces. You can tie and untie them," he said.

While it is medically possible to reverse the operation when the tubes have not been fully removed, just cauterized, clipped or folded, most doctors won't do so, Rubenstein said. When they are done, reversal surgeries enable about 73% of patients to get pregnant and 53% to give birth, a review of 135 cases found.

In contrast, Rubenstein described in vitro fertilization (IVF) success rates in such situations as "exceptional." In other words, "we would recommend to that patient to have an IVF cycle and then a transfer of that embryo into the uterus rather than trying to reconnect the tubes." IVF never requires an egg to travel through the tubes, so the procedure would still work for a person lacking tubes.

This article is for informational purposes only and is not meant to offer medical advice.

However, our expert, Melanie Carver, Chief Mission Officer at the Asthma and Allergy Foundation of America, suggests finding out if your room needs humidifying before purchasing one of the best humidifiers. She said, "A device known as a hygrometer (humidity sensor) can help you make this determination. It measures the relative humidity (RH) in your space. Ideally, your indoor space should be between 30-50% RH. The climate where you live, your home’s air ventilation and your indoor activities all affect your humidity levels."

But what should you look for in a humidifier? There are so many options out there that understanding all the terminology and functions can feel overwhelming. When choosing a humidifier for your home, there will be certain things to consider such as the room size, the space you have available to place the humidifier in, the style you'd prefer and the room you're placing it in, as, for example, if you're placing it in the bedroom you will want a quieter option. These are just a few of the things to consider.

While some of the best humidifiers may tick many boxes, the likelihood is that you'll have to compromise on something. Our advice is to consider what's most important to you and go from there. We've provided some more guidance below to help you understand what to consider when purchasing a humidifier.

We have years of experience in testing various humidifiers so we know what to look for. We will share with you our knowledge so you feel empowered to find the best humidifier for you. We'll take you through what to look for, step-by-step, so the next time you're searching, you feel confident. Let's see if we can get your home humidified in time for the warmer summer months...

Consider the room size

Some people may think that any humidifier can handle any space but this isn't the case. It's important to consider your room size when deciding which humidifier to purchase. Our expert, Melanie Carver, Chief Mission Officer at the Asthma and Allergy Foundation of America, explained the impact low humidity can have, "Low humidity can cause your skin to dry out as well as your eyes, nose and lips. It can result in a dry, sore throat as well as worsen eczema and asthma. If your humidity levels are below 30%, you can add moisture to the air by using a humidifier." She added, "Using an appropriate humidifier in your space can help to keep the humidity in your home at a healthy level."

Humidifiers came in various sizes from small to large. Small humidifiers, you guessed it, can handle smaller spaces, while the larger ones can effectively humidify larger rooms. Ensuring you get the right-sized humidifier for your space is key. If you end up with one that's too small for your space, it won't be able to provide the optimum humidity levels. This means you won't be receiving the benefits of having a humidifier — the air pollutants won't be reduced and the added moisture won't be enough to sustain that ideal humidity level as previously discussed by our expert, Melanie Carver.

On the other hand, if you purchase a large humidifier for a small room, you may find that the room becomes too humid. Too much humidity in a room or house can be an issue, causing damp and mold spores. Melanie warns of this complication, "High humidity causes the air to feel warmer than it actually is. This can cause you to overheat. It also encourages the growth of dust mites and mold (both of which can trigger asthma and allergies). They thrive in high humidity above 50%. If your indoor space is above 50%, you can reduce the humidity levels by improving your ventilation, using air conditioning or using a dehumidifier to remove moisture from the air. You obviously want to avoid causing any further issues, so we argue that selecting the right-sized humidifier for your space is paramount in your purchasing decision."

In order to understand what size humidifier is appropriate for your space, check the specifications. Most manufacturers make it very clear what size room their humidifier can work most effectively in.

What noise level is appropriate for you?

Once you're clear which room you're placing your humidifier in and you've got the right-sized humidifier for that space, next you should consider the noise level of the humidifier itself. This may be particularly important if, for example, you are placing it in the bedroom and want it to run overnight.

There are a couple of ways to work out what the noise levels of a humidifier may be like, even if the manufacturer doesn't mention this specifically in their description. In our best humidifiers guide, we tested some models with a decibel meter but we don't expect you to go round shops and do this. Generally speaking, ultrasonic humidifiers tend to be the quietest. This is because they use a high-frequency vibration to create the mist that's released into the air. These are a good option if you're looking for a humidifier that won't distract you or keep you awake.

You can also consider whether you want to have a warm or cool mist humidifier. Melanie Carver, our expert, offers some advice on this front: "There are different types of humidifiers that release water vapor or steam or mist into the air. For people with young children in the home, opt for a cool mist or ultrasonic option rather than a steam vaporizer to reduce the risk of burns."

Cool mist humidifiers use a fan to disperse the water into the air and are known as evaporative humidifiers. Conversely, warm mist humidifiers use a heating element to create steam that evaporates into the air. As cool mist humidifiers use a fan, this may make them slightly louder than warm mist humidifiers, so this is worth keeping in mind.

Ultimately, it is about whether or not you are distracted by noises in your home or if you find background noise calming. No humidifier is so unbearingly loud you won't be able to deal with it, but saying that, we all have our own tolerances to noise. If you're sensitive to background noises or hums, we suggest going for an ultrasonic humidifier for minimal noise disturbance.

And what about maintenance?

Many people may not think that humidifiers require maintenance but they do and this is something to bear in mind if you're thinking of buying one. There are many ways you can ensure the smooth running and longevity of your humidifier. A regular cleaning will do wonders, while others suggest using only distilled or soft water. This is because the type of water in your home can impact the lifespan of your humidifier. For example, hard water can contribute to mineral buildup. This buildup can make your humidifier less effective due to blockages in water flow, with it even causing damage to the humidifier's components. On the other hand, soft water is much less likely to have these effects, with soft or distilled water being recommended over hard water. Of course, if you live in a hard water area, you will have to rely on distilled water if you want to keep your humidifier in top condition.

Our expert, Melanie Carver, offers further suggestions for an optimal clean: "Clean your device per the manufacturer’s instructions. If you don’t have the manufacturer’s recommendations, the Environmental Protection Agency (EPA) recommends a 3% hydrogen peroxide solution may be useful for cleaning humidifiers. A scrubbing brush can be helpful to reach small areas or corners." She added, "The Asthma and Allergy Foundation of America also recommends just plain soap and water for the collection tank/reservoir parts of the machines. Do a thorough rinse and dry whenever cleaning with soap or any other cleaning solution."

Furthermore, it is recommended that you change the water daily and keep on top of any mineral buildup by performing a thorough clean every few days. Our expert, Melanie Carver, explained there were signs to watch for that will help you identify when your humidifier is due a clean, "If you see build-up or discoloration on any part of the humidifier — water tank, reservoir, base, etc. that is a sign it needs cleaning and could indicate mold growth." Humidifiers also have filters that will need changing as per the manufacturer's guidance.

So, as you can see, having a humidifier working effectively in your home isn't a case of plugging it in, filling the tank and leaving it. To get the most out of these devices, it's important to consider how much time you can give towards cleaning and maintaining them to ensure their longevity.

Consider any extra features

Now we've covered selecting the right-sized humidifier for your space, the potential noise levels to be aware of and how to maintain your new investment, we move on to the features of humidifiers. While the basics of what they do are similar (adding moisture to the air through various means, be that ultrasonic, fan-based or through a heating element), there are differences in the extra features that they offer.

However, there are some key features to look for. Melanie Carver, our expert, explained, "The most important features include automatic shut-off and a humidity sensor that measures and displays your room’s relative humidity so you can keep the space within 30-50% RH."

The automatic shut-off feature is a good idea, especially if you want to leave the humidifier running while you've popped out. When the tank is running low, if a humidifier has this function, it will shut off. This is a safety feature that gives peace of mind. However, the runtimes on humidifiers vary dramatically, with some lasting only 60 minutes and others 50 hours or more. Runtimes may impact whether you think an automatic shut-off feature is essential, as if it only runs for a total of an hour, you may be around within that time to shut it off yourself. Automatic shut-offs can be more useful for those who go to work all day and would prefer to leave the humidifier running while they are out. There are other differences in features such as the addition of lights. You will need to consider the placement of your humidifier and whether, for example, lights will be a nice addition or just cause irritation as they may light the bedroom up at night.

This is not an exhaustive list of features, with some, such as the PureGuardian H950AR humidifier, having a separate oil tank to allow you to infuse the moisture with essential oils. However, our expert, Melanie Carver, advised that infusing the moisture with fragrances may not be a helpful feature for those with asthma: "Some humidifiers have a feature for you to add fragrances. Fragrances are a common asthma trigger, and so the Asthma and Allergy Foundation of America does not recommend adding fragrances to any air care device."

We recommend you look at the product details closely to get an understanding of what else the humidifier offers to see if it suits your needs.

How much do they cost to run?

One of the big considerations for you may be the cost of running a humidifier. Luckily, the cost of running a humidifier is generally low, with them costing less than running an air conditioning unit, for example. As with any electrical appliance, the running costs will depend on how often you use it and the rates of your electricity.

Our expert, Melanie Carver, offers further advice, "The power consumption of humidifiers is going to be dependent on the type of humidifier you are using and how often it runs. Ultrasonic humidifiers tend to consume less energy than cool mist or steam vaporizers. The EPA’s Energy Star certification has been a helpful resource for consumers to identify appliances that use less energy. But the Energy Star program does not certify humidifiers."

Our expert

So is there a clear link between cannabis and cancer, and if so, what causes it?

Each lungful of cannabis smoke is a brew of the high-inducing ingredient tetrahydrocannabinol (THC), fine particulates, and certain carcinogens that are also found in tobacco. But cannabinoids may bring their own twist by quietly rewiring the lungs' immune settings.

"The airway's protective lining weakens, antiviral signals falter, and inflammation flares," said Raphael Cuomo, a scientist working at the intersection of cancer prevention and addiction at the University of California, San Diego. In one study with mice, cannabis smoke dulled both tumor-fighting and infection defenses. In another, THC blunted the effects of immunotherapy, weakening tumor-killing immune cells in the body.

Cannabis also triggers other changes in the immune system, according to studies in humans, cells and lab mice. In the airways, levels of proteins tied to inflammation spike when cannabis is used consistently. A protein called MUC5AC, which lines and protects the respiratory tract, is made in excess in certain cells, hinting at early tissue changes. Cannabis smoke can skew the enzymes that maintain tissue and switch off genes that respond to toxins.

The responses of the lungs' patrol cells — alveolar macrophages — can be stunted. And in the blood, shifts in cellular messengers called cytokines and faint changes in epigenetics become a molecular diary of exposure.

Related: Could cannabis treat cancer someday? Here's what the science says so far

In summary, "cannabis smoke, from its toxic byproducts to THC, can irritate lungs and weaken immunity," Sayantan Bhattacharyya, a cancer systems biologist who will soon be a senior postdoctoral scientist at the University of Limerick in Ireland, told Live Science.

But immune disruption is only one factor that might raise cancer risk. Cannabis smoke may also tug on deeper levers inside cells — the molecular switches that cancers use to grow and spread.

Among these, few are as infamous as the epidermal growth factor receptor, or EGFR. In one of the few studies of its kind, Bhattacharyya examined 83 men with glottic cancer, which affects the voice box, and found that cannabis smokers in the group had markedly higher activation of EGFR and related cancer proteins than either tobacco smokers or nonsmokers.

"EGFR governs [cell] growth, repair, and survival," Bhattacharyya said. "In cannabis smokers, constant activation can fuel unchecked proliferation, speed genetic damage, and hasten the leap toward cancer — triggering earlier onset, faster spread, and treatment resistance." That said, Bhattacharyya's study included only 83 people with one type of cancer, so more work is needed to know if the results are broadly applicable.

Bhattacharyya sees two priorities for future research. One is to develop realistic lab models — such as "organoids," 3D-printed tumors and organ chips — to study how cannabis amplifies EGFR. The other is to probe potentially dangerous additives that might be lurking in unregulated cannabis products, he said.

For all the unsettling biology uncovered in laboratory studies, real-world studies of cannabis smokers tell a mixed story. Some research links heavy cannabis use to higher cancer risk, while others find no clear connection. Still, Cuomo maintains that long-term use of the drug may increase the odds of developing cancer, based on what we know so far.

For people who already have cancer, however, Cuomo has shown that cannabis use isn't linked to an earlier death — a puzzle researchers now call "Cuomo's paradox." In fact, studies have found that, in cancer patients, cannabis can boost appetite and curb chemotherapy-induced nausea, even as its smoke may potentially be planting the chemical and cellular seeds of disease.

The challenge going forward will be to accurately assess both the benefits and harms of cannabis in order to weigh them against one another.

Editor's note: This story was updated on Aug. 21, 2025, to note that Bhattacharyya will hold a position at University of Limerick.

This article is for informational purposes only and is not meant to offer medical advice.

With every brand having a whole host of models, and there being dozens of brands to choose from in the first place, it’s not always easy to establish where to start. Then there’s the dilemma of price — an all-singing, all-dancing Garmin or Apple Watch model might be the best on paper, but they don’t come cheap.

Thankfully, we’re here to take some of the confusion out of the equation, offering our best fitness trackers for beginners as well as what makes an ideal first model for newcomers to running, visiting the gym, or just step-tracking.

The quick list

See the quick list below for a short overview of our favorite fitness trackers for beginners, and look further below on this page to find a deeper dive into each.

The best fitness trackers for beginners we recommend in 2025

Best beginner-friendly fitness tracker for iOS users

We’ll start with an Apple Watch because if you’ve got an iPhone, it’ll naturally be of interest (more on OS compatibility later), but it’s also worth noting that the 2nd generation Apple Watch SE is currently almost three years old and seemingly due for an update.

In any case, it’s a comfortable watch that has access to a whole host of apps thanks to watchOS, which lets it run the likes of Strava and other apps natively, while also being light and easy to wear all day.

It’s worth noting that Apple Watch models are less fitness trackers and more smartwatches (and there is a difference). Apple Watch SE 2nd Gen is able to run a whole host of apps, but that comes at the cost of battery life.

So, while it can deal with sleep tracking and counting your steps, it will need to be charged at the end of each day. If you’re looking for something more focused on health and wellbeing, which doesn’t need more advanced features, another option on this list might be more appropriate.

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Best budget smartwatch for beginners

We’re following up with the Amazfit Active because, at quick glance, you could be forgiven for thinking it’s an Apple Watch at a massively reduced price.

It has much better battery life, too, running for a whole month before needing a charge, it’s light as a feather, and it’s a very accurate tracker, too. The design is perhaps a little cheap to the touch, but that’s perhaps to be expected at this price point.

It’s easy to set up, and comes in much cheaper than many of its rivals on this list, but it’s worth considering that cheaper construction if you’re planning to run a more intense trail. If you were to fall, or you’re expecting tougher conditions, you might find the materials used don’t stand up to scrutiny.

Read more: Amazfit Active review

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Best affordable Garmin watch for beginners

Garmin’s fitness trackers have grown consistently in quality (and popularity) in recent years, but they’ve also gotten a fair bit pricier at the top end.

Thankfully, the Forerunner 165 is an ideal starter watch. It melds the manufacturer’s excellent GPS and heart-rate tracking with a big, easy-to-read OLED display, while keeping the price down at around £250/$250 (although it’s often discounted).

You can add music storage with the 165 Music variant, but it’ll cost you to do so. It’s still not exactly what we’d call “cheap”, despite being much more affordable than its siblings.

Still, it keeps many of the Garmin training features and that all-important GPS tech without breaking the bank.

Read more: Garmin Forerunner 165 review.

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Best beginner-friendly fitness tracker for streaming music

Coros has become a bit of an industry disruptor in recent years by offering more affordable fitness trackers that pack a whole host of features.

The Pace 3 might be the best yet, with a comfortable watch and the option to play music from the watch (something surprisingly rare in the current fitness tracker landscape). Tracking is accurate, too, getting close to Garmin's levels of GPS accuracy but at a lower price point.

We admit we’d have preferred an OLED or AMOLED display, but the one here is still at least large enough for more casual users; it just isn’t as easy to read in all lighting conditions as the others on this list.

Still, the Coros Pace 3 is packed with features, including training plans, built-in GPS, and plenty of sensors, all for less than you’d spend on something like a Garmin.

Read more: Coros Pace 3 review.

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Best budget fitness tracker for beginners

One of our favorite budget fitness trackers, this Xiaomi model will set you back just $49.99/£34.99, but we’ve seen it going for half of that in discount events.

It’s small and discreet but has plenty of fitness-tracking potential across 150 sports modes, heart rate, oxygen saturation, sleep tracking and more. It lacks built-in GPS, instead piggybacking off of your phone’s signal, but at this price, it’s hard to complain.

Despite its relatively small size, it’s very easy to read thanks to a vibrant AMOLED screen that’s ideal in all conditions, and despite the smaller size, it’s intuitive enough for newcomers to use it.

Read more: Xiaomi Smart Band 9 review

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Best smartwatch for Android users

This fantastic (and affordable) fitness tracker is larger than some on this list, but still comfortable. It has a big, 1.43-inch AMOLED display that’s easy to read, and has a whopping 45 days of battery life on a single charge.

It’s also rugged enough for anyone running trails or doing some light climbing, with our main issue being that it doesn’t work with iOS. That’s a shame, because we called it our favorite Garmin alternative.

It manages to walk the line between affordability and ruggedness that none of its rivals can quite manage, and while the large chassis won’t be for everyone, it does give the big display plenty of opportunity to show information.

The Snapdragon W5+ chip under the hood means it works perfectly with all that Wear OS can offer, too.

Read more: TicWatch Atlas review

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Best fitness trackers for beginners: comparison

Contributing experts

How to choose the best fitness tracker for a beginner

Every user will have different needs, but these are some things to consider when picking your first fitness tracker.

Screen size and technology

Some fitness trackers are relatively tiny, but that means a smaller display. That won’t suit everyone, particularly if you want to read messages mid-workout or make adjustments to your route.

It’s also worth considering the screen technology used. AMOLED and OLED displays are not only brighter, but they tend to be easier to read while outdoors.

“When someone is just starting out with a fitness tracker, the most important thing is ease of use,” Jay Wirsig, CEO of KayaArm explains.

“A large, readable screen helps more than people realize, especially if you are checking stats mid-hike or while moving. Bright sunlight can make smaller displays hard to read, so visibility is key for outdoor use.”

Ease of use and companion app

Many of the best fitness trackers are packed with impressive features and gizmos, but unless you’re desperate to use them, they can increase the knowledge barrier needed to get the most out of them.

The models on this page are easier to use thanks to intuitive companion apps for tracking your data and monitoring your progress, and the on-device UI is easy to get to grips with, too.

“If someone cannot understand the app within a few minutes, they are unlikely to open it again,” Wirsig explains. “A good beginner setup keeps focus on a few easy-to-follow metrics instead of flooding the user with complicated dashboards.”

OS compatibility

If you’ve got an iPhone or Android phone, that’ll dictate which fitness tracker options are available to you. After all, an Apple Watch won’t work on a Google phone, while the same can be said the other way around with Wear OS watches on iOS phones.

Aside from the Apple Watch SE and Ticwatch Atlas on this list, every device has a companion app that can be installed on either platform.

Comfort

Above all else, it’s important that your fitness tracker is comfortable; otherwise, you might not want to wear it at all.

Thankfully, the options on this list are just that, and with some offering battery life up to a month and a half, you’ll be able to keep it on your wrist for weeks.

GPS

“For outdoor activity, GPS is where a tracker really becomes useful,” Wirsig notes.

“Whether you are paddling, walking trails, or even gardening, built-in GPS lets you see where you went and how far. It also helps when tracking elevation changes or actual pace, which is more useful in the outdoors than counting steps alone.”

Price

“Price does matter, especially when someone is not sure how long they will stay committed,” Wirsig adds.

“A lower-cost device that tracks basic steps, heart rate, and sleep is often more than enough in the early stages. It helps get a feel for patterns without the pressure of a big investment.”

Latest updates

How we tested these fitness trackers

How we test the best fitness trackers for beginners

We test all fitness trackers to the exact same standard, using the same procedures. After spending at least two weeks with each wearable, we rank it across the following categories:

1) Design. We check the tracker's size, shape and general appearance, and assess whether it is comfortable to wear and sufficiently customizable (for example, whether it has removable straps and different size options). We also look into its durability and waterproofness, and inform you of any scuffs and scratches that the testing unit may have sustained during testing.

2) Display. We check the size, brightness and resolution of the screen, and whether it comes with any protective measures (scratch-resistant Gorilla glass, for example) or any other design solutions that can enhance user experience. We also review the touchscreen's responsiveness and report any screen issues we may have experienced during testing.

3) Features. We try to answer the following questions: Which health metrics and activities does this fitness tracker measure? How in-depth and well-explained are they? Does it come with any smart features, such as voice control and compatibility with third-party apps? Can it store music, pay for your groceries or take your phone calls?

4) Performance. We put the fitness tracker through a range of activities to test its battery life, general tracking accuracy and app connectivity. Most importantly, we assess the validity of its heart rate tracking features using a chest-strap heart rate monitor (such as the Polar H9), and (if applicable) compare its GPS readings to a more high-end navigation system.

Verdict. Finally, we calculate a final score out of five and advise on the pros and cons of the fitness tracker in question.

Emergency personnel were dispatched to a trailhead in the Savage Gulf State Park on Aug. 8. Medical workers gave the man CPR on the trail and transported him to a hospital, where he died. The man's identity has not been made public.

Witnesses said the hiker picked up the Rattlesnake, resulting in a bite to his hand, Matthew Griffith, director of the Grundy County Emergency Management Agency, told Live Science. The snake is believed to be a timber rattlesnake (Crotalus horridus), a species with potent venom but one that rarely bites humans unless provoked or stepped on.

"It is believed that the hiker had an allergic reaction however full details of actual cause of death have not been released," Griffith said in an email.

Venomous snake bites are rarely fatal in the U.S. Around 7,000 to 8,000 people are bitten by venomous snakes each year, and only about five of these result in a fatality, according to the Centers for Disease Control and Prevention (CDC). Most fatalities happen because of immediate anaphylactic reactions or because the person bitten doesn't seek medical attention.

Related: Cobra venom kills by collapsing blood vessels, organ-on-a-chip shows

Timber rattlesnakes are the largest and most dangerous venomous snakes in Tennessee, with heavy bodies that can grow up to about 5 feet (1.5 meters) long, according to the Tennessee Wildlife Resources Agency. The other venomous snakes in the state are pygmy rattlesnakes (Sistrurus miliarius), copperheads (Agkistrodon contortrix) and cottonmouths (Agkistrodon piscivorus).

These snakes use their venom to hunt prey and for defence. Timber rattlesnakes normally eat small mammals such as squirrels and rats but will also occasionally hunt birds and reptiles. This species is an ambush predator, remaining still at the base of trees or beside fallen logs, waiting for prey to pass. Rattlesnakes can strike quickly from any position and do not always rattle before biting, according to the CDC.

Timber rattlesnakes aren't aggressive toward humans and avoid contact with people and pets if they can, according to the Florida Museum. If they do bite, there's also a small chance they won't inject their venom. This kind of strike is known as a dry bite and accounts for about 20% of all defensive rattlesnake bites, according to the Arizona-Sonora Desert Museum.

Snake venom is a complex mix of proteins that varies dramatically across different species and their populations. Rattlesnakes are vipers, which typically have haemotoxic venom that attacks the circulatory system. Haemotoxic venom causes bleeding and disrupts the blood's ability to clot, according to the Natural History Museum in London. However, rattlesnakes can also have neurotoxic venom, which attacks the nervous system. Timber rattlesnakes are known to have properties of both and can be equipped with extremely potent neurotoxic venom that lacks the hemorrhagic effects typical of rattlesnakes. Rattlesnake venom is also cytotoxic, which is destructive to tissue.

William Sutton, a professor at Tennessee State University who studies snakes, told The New York Times that a snake venom allergic reaction can be similar to a bee sting allergic reaction, with the potential to send someone into anaphylaxis, during which a person's airways narrow and their blood pressure lowers.

While rattlesnake bites aren't normally fatal with medical treatment, the venom can have long-term consequences. Around 10% to 44% of those bitten experience lasting injuries, such as losing part or all of their finger.

Griffith warned people engaging in outdoor activities to be mindful of venomous snakes and not to handle them.

"As always, it's strongly recommended to have some kind of first aid supplies while enjoying outdoor recreational activities and be mindful of wildlife and the dangers that some wildlife may pose," Griffith said. "If you encounter a snake simply remain calm and do not attempt to handle it. If bitten seek immediate medical attention."

The symptoms: The patient reported to an outpatient clinic after noticing a change in his typical migraine symptoms. Over the previous four months, medications were no longer effective in treating his migraines, and they started occurring more frequently than usual — about once a week — while also becoming more severe. He also reported worsening pain across the back of his skull.

What happened next: Doctors took the man's vital signs, which were not out of the ordinary. They also took a CT scan of his brain, which revealed numerous cyst-like lesions scattered throughout both hemispheres. Specifically, these growths appeared in the organ's white matter, the insulated wiring that extends off brain cells.

The patient was immediately admitted to the hospital for a neurosurgical consultation. An MRI backed up what was seen on the CT scan, but it also revealed a buildup of fluid around the cysts in the man's brain.

The diagnosis: Suspecting a possible parasitic infection, the neurosurgery department sent the patient to infectious disease specialists, who ran a number of tests. One test showed that the man's blood carried antibodies against Taenia solium, a tapeworm typically found in pigs — lodging in their intestines and muscles and passing in their feces. In the man's case, the worm's larvae had invaded his brain and were embedded within cysts inside the tissue. When T. solium infects the nervous system in this way, the condition is known as neurocysticercosis.

The treatment: The patient received antiparasitic and anti-inflammatory drugs while being monitored in the intensive care unit for several weeks, after which he was seen at an infectious disease outpatient clinic. "The patient was successfully treated, with regression of lesions and improvement of headaches," his doctors wrote in a report of the case.

What makes the case unique: Humans can be infected by T. solium when they inadvertently consume the worm's larvae or eggs. People can end up being exposed if they eat undercooked pork, for instance, or if they drink water contaminated with the feces of infected pigs or touch their faces or food after touching pig poop.

Consuming undercooked pork containing the larvae can cause an intestinal infection called taeniasis, while consuming feces containing the eggs triggers infections in other tissues, including the brain. The eggs initially travel into the brain's blood vessels and compartments for cerebrospinal fluid, the clear fluid that bathes the brain, and they then trigger inflammatory immune responses that break down the brain's protective barrier.

T. solium is endemic to many regions of the world, including various parts of Central and South America, Africa and Asia, which means the parasitic infection regularly spreads in those locations. In fact, in these endemic areas, neurocysticercosis is a common cause of epilepsy, according to the World Health Organization. While the infection is not endemic to the United States, about 2,000 or so cases are reported in the country each year, and they are often related to travel to and from places where T. solium is endemic.

But in the man's case, he "denied recent travel to high-risk areas, with his only notable travel history being attendance on a cruise to the Bahamas 2 years prior," the report noted. (There is minimal data on whether T. solium is present in the Bahamas.)

Upon further questioning, the man "admitted to a habit of eating lightly cooked, non-crispy bacon for most of his life," the report said. The Food and Drug Administration recommends cooking pork to at least 145 degrees Fahrenheit (about 63 degrees Celsius), though it can be difficult to check the temperature of bacon, given it's a thin cut of meat. However, if cooked until crisp, it should have reached a safe temperature, according to the U.S. Department of Agriculture.

Based on the man's eating habits, his doctors concluded that his "lifelong preference for soft bacon" may have led him to eat undercooked bacon occasionally, leading to taeniasis, the intestinal form of the tapeworm infection. From there, he may have accidentally given himself cysticercosis via improper handwashing, the doctors speculated. In other words, he may have inadvertently been exposed to the worm's eggs in his own feces.

"Undercooked pork consumption is a theoretical risk factor for neurocysticercosis via autoinoculation, as we suspected in this case," the medical team concluded. "It is historically very unusual to encounter infected pork in the United States, and our case may have public health implications."

This article is for informational purposes only and is not meant to offer medical advice.

And while the recall initially only affected products sold by Walmart, the agency has widened its recall to include products sold by another distributor.

The products were processed by PT. Bahari Makmur Sejati, also referred to as BMS Foods. The FDA launched an investigation after U.S. Customs officials detected cesium-137 (Cs-137) — a radioactive form of cesium — in shipping containers carrying the shrimp that were delivered to Los Angeles; Houston; Savannah, Georgia; and Miami.

Analyses of the containers' contents confirmed the presence of Cs-137 in one sample of breaded shrimp. The containers that tested positive were not allowed to enter the U.S., and no products that tested positive have entered the food supply.

However, as a precaution, the FDA has looked into other shrimp products that were imported from the same company but prior to the detection of Cs-137. Despite those previously imported products not testing positive for radioactive material at the time, the FDA has recommended people not consume them and that retailers recall them.

"To date, FDA has learned that Walmart has received implicated raw frozen shrimp, imported after the date of first detection of Cs-137 by CBP [Customs & Border Patrol], but from shipments that did not alert for Cs-137," the statement says. BMS Foods has clearly handled products under conditions that would open the door to Cs-137 contamination, the agency explained, so there's a possibility these other products could pose a safety concern, as well.

As such, the FDA recommended that Walmart recall the affected products, and it lists the specific lot numbers affected in its warning. Anyone who has recently bought frozen shrimp from Walmart that matches the descriptions released by the FDA should throw it away and not eat or serve it.

On Thursday (Aug. 19), the FDA announced that more frozen shrimp are potentially affected by the issue. They've issued a recall of bagged, frozen shrimp distributed by Southwind Foods, LLC of Carson, California between July 17 and Aug. 8. The recalled products were distributed or sold in Alabama, Arizona, California, Massachusetts, Minnesota, Pennsylvania, Utah, Virginia, and Washington.

Related: How radioactive is the human body?

According to the FDA, the nonradioactive form of cesium, called stable cesium, naturally occurs in the environment and is found in rocks, soil and dust. The element can also travel long distances through the air, before settling on the ground or in water. Cesium can become radioactive when it's exposed to decaying uranium, nuclear explosions or nuclear reactor accidents. Cesium-137 has a half-life of about 30 years, meaning it takes three decades for the isotope's radioactivity to decrease by half.

"Because it is widespread worldwide, trace amounts of Cs-137 can be found in the environment, including soil, food, and air," the FDA statement noted. The agency evaluates any detection of the isotope in food products to determine if follow-up action is warranted.

The FDA found Cs-137 in only one of the BMS shrimp products tested, but that does not necessarily mean other products aren't also contaminated, the agency noted. The amount of the isotope found in the breaded shrimp sample was not high enough to cause immediate harm to a consumer in the short term, the tests suggested.

However, the level detected could pose a risk if someone were to consume the product repeatedly over a longer period of time, especially when you combine that exposure with the baseline, low-level radiation that we're exposed to in the environment and through routine medical procedures, such as X-rays. Over the long term, repeated exposure to Cs-137 could raise the risk of cancer by damaging DNA.

The FDA's investigation into the situation is ongoing, but the agency has already confirmed that products from BMS Foods have violated the Federal Food, Drug, and Cosmetic Act. That's because the products appear to have been "prepared, packed, or held under insanitary conditions whereby it may have become contaminated with Cs-137 and may pose a safety concern," the statement explains.

The company has been added to a new import alert for chemical contamination, which effectively stops any of its shrimp products from entering the U.S. until the company corrects those underlying violations.

At this point, the root cause of the contamination is unknown, but the FDA is "working with Indonesian seafood regulatory authorities to investigate."

"FDA will continue working with industry to trace all implicated products processed by PT. Bahari Makmur Sejati through the supply chain to gather as much information about them as possible and take action as appropriate," FDA officials said in the statement.

Editor's Note: This story was updated on Friday, Aug. 22 at 4:45 p.m. EDT to note that the frozen shrimp recall has now been expanded to include products from an additional distributor.

This article is for informational purposes only and is not meant to offer medical advice.

After extracting keratin — a protein found in hair, skin and fingernails — from wool and applying it to teeth, scientists found that the substance formed a protective crystal-like coating that mimicked natural tooth enamel.

The finding could support sustainable, low-cost treatments for early tooth decay within the next two to three years, according to the researchers.They reported their findings August 12 in the journal Advanced Healthcare Materials.

"Keratin offers a transformative alternative to current dental treatments," study coauthor Sara Gamea, a dentistry researcher at King's College London, said in the statement. "Not only is it sustainably sourced from biological waste materials like hair and skin, it also eliminates the need for traditional plastic resins, commonly used in restorative dentistry, which are toxic and less durable. Keratin also looks much more natural than these treatments, as it can more closely match the color of the original tooth."

Untreated tooth decay is the world's most common oral health condition, affecting some 2 billion people worldwide. Over time, acidic foods, poor oral hygiene, and everyday wear and tear can break down the protective enamel that covers a person's teeth. Losing that enamel can lead to pain, cavities and tooth loss.

"Unlike bones and hair, enamel does not regenerate," study coauthor Sherif Elsharkawy, a researcher specializing in prosthodontics at King's College London, said in a statement. "Once it's gone, it's lost forever."

Related: Scientists transform pee into material fit for medical implants

To investigate whether keratin-based treatments could help stop tooth decay and repair enamel, Elsharkawy and his colleagues first extracted keratin from wool fibers. Then they mixed the keratin with water, where it formed a thin film.

After applying the keratin film to a tooth sample, the scientists found that it formed an ordered, strong and crystal-like coating similar to biological enamel when it came in contact with minerals in saliva. Over the course of a month, the coating attracted calcium and phosphate ions, building up a hard, protective layer over the tooth.

The scientists are exploring ways to bring the keratin treatment to the public. Keratin toothpastes for daily use or professional coatings applied at a dentist's office could be available within the next few years, according to the statement.

"We are entering an exciting era where biotechnology allows us to not just treat symptoms but restore biological function using the body's own materials," Elsharkawy said. "With further development and the right industry partnerships, we may soon be growing stronger, healthier smiles from something as simple as a haircut."

The results could help people who are unable to speak communicate more easily with others. Unlike some previous systems, the new brain-computer interface does not require people to attempt to physically speak. Instead, they just have to think what they want to say.

"This is the first time we've managed to understand what brain activity looks like when you just think about speaking," study co-author Erin Kunz, an electrical engineer at Stanford University, said in a statement. "For people with severe speech and motor impairments, [brain-computer interfaces] capable of decoding inner speech could help them communicate much more easily and more naturally."

Brain-computer interfaces (BCIs) allow people who are paralyzed to use their thoughts to control assistive devices, such as prosthetic hands, or to communicate with others. Some systems involve implanting electrodes in a person's brain, while others use MRI to observe brain activity and relate it to thoughts or actions.

But many BCIs that help people communicate require a person to physically attempt to speak in order to interpret what they want to say. This process can be tiring for people who have limited muscle control. Researchers in the new study wondered if they could instead decode inner speech.

In the new study, published Aug. 14 in the journal Cell, Kunz and her colleagues worked with four people who were paralyzed by either a stroke or amyotrophic lateral sclerosis (ALS), a degenerative disease that affects the nerve cells that help control muscles. The participants had electrodes implanted in their brains as part of a clinical trial for controlling assistive devices with thoughts. The researchers trained artificial intelligence models to decode inner speech and attempted speech from electrical signals picked up by the electrodes in the participants' brains.

The models decoded sentences that participants internally "spoke" in their minds with up to 74% accuracy, the team found. They also picked up on a person's natural inner speech during tasks that required it, such as remembering the order of a series of arrows pointing in different directions.

Inner speech and attempted speech produced similar patterns of brain activity in the brain's motor cortex, which controls movement, but inner speech produced weaker activity overall.

One ethical dilemma with BCIs is that they could potentially decode people's private thoughts rather than what they intended to say aloud. The differences in brain signals between attempted and inner speech suggest that future brain-computer interfaces could be trained to ignore inner speech entirely, study co-author Frank Willett, an assistant professor of neurosurgery at Stanford, said in the statement.

As an additional safeguard against the current system unintentionally decoding a person's private inner speech, the team developed a password-protected BCI. Participants could use attempted speech to communicate at any time, but the interface started decoding inner speech only after they spoke the passphrase "chitty chitty bang bang" in their minds.

Though the BCI wasn't able to decode complete sentences when a person wasn't explicitly thinking in words, advanced devices may be able to do so in the future, the researchers wrote in the study.

"The future of BCIs is bright," Willett said in the statement. "This work gives real hope that speech BCIs can one day restore communication that is as fluent, natural, and comfortable as conversational speech."

Panel members discussed adding a so-called black box warning to the drugs — which the agency uses to indicate severe or life-threatening side effects — about the risk they pose to developing fetuses. Some of the panelists who attended had a history of expressing deep skepticism on antidepressants.

SSRIs include drugs like Prozac and Zoloft and are the most commonly used medicines for treating clinical depression. They are considered the first-line medications for treating depression in pregnancy, with approximately 5% to 6% of North American women taking an SSRI during pregnancy.

We are a psychologist certified in perinatal mental health and a reproductive psychiatrist and neuroscientist who studies female hormones and drug treatments for depression. We are concerned that many claims made at the meeting about the dangers of those drugs contradict decades of research evidence showing that antidepressant use during pregnancy is low risk when compared with the dangers of mental illness.

As clinicians, we have front-row seats to the maternal mental health crisis in the U.S. Mental illness, including suicide and overdose, is the leading cause of maternal deaths. Like all drugs, SSRIs carry both risks and benefits. But research shows that the benefits to pregnant patients outweigh the risks of the SSRIs, as well as the risks of untreated depression.

The panel did not address the safety of SSRIs following delivery, but numerous studies show that taking SSRI antidepressants while breastfeeding is low risk, usually producing low to undetectable drug levels in infants.

Related: 'Love hormone' oxytocin can pause pregnancy, animal study finds

The biology of maternal brain health

Pregnancy and the months following childbirth are characterized by so many emotional, psychological and physical changes that the transition to motherhood has a specific name: matrescence. During matrescence, the brain changes rapidly as it prepares to efficiently take care of a baby.

The capacity for change within the brain is known as "plasticity." Enhanced plasticity during pregnancy and the postpartum period is what allows the maternal brain to become better at attuning to and carrying out the tasks of motherhood. For example, research indicates that during this period, the brain is primed to respond to baby-related stimuli and improve a mother's ability to regulate her emotions. These brain shifts also act as a mental buffer against aging and stress in the long term.

On the flip side, these rapid brain changes, fueled by hormonal shifts, can make people especially vulnerable to the risk of mental illness during and after pregnancy. For women who have a prior history of depression, the risk is even greater.

Clinical depression interferes with brain plasticity, such that the brain becomes "stuck" in patterns of negative thoughts, emotions and behaviors.

This leads to impairment in brain functions that are essential to motherhood. New mothers with depression have decreased brain activity in regions responsible for motivation, regulation of emotion and problem-solving. They are often withdrawn or overprotective of their infants, and they struggle with the relentless effort needed for tasks that arise with child-rearing like soothing, feeding, stimulating, planning and anticipating the child's needs.

Research shows that SSRIs work by promoting brain plasticity. This in turn allows individuals to perceive the world more positively, increases the experience of gratification as a mother and facilitates cognitive flexibility for problem-solving.

Assessing the risks of SSRIs in pregnancy

Prescription drugs like SSRIs are just one aspect of treating pregnant women struggling with mental illness. Evidence-based psychotherapy, such as cognitive behavioral therapy, can also induce adaptive brain changes. But women with severe symptoms often require medication before they can reap the benefits of psychotherapy, and finding properly trained, accessible and affordable psychotherapists can be challenging. So sometimes, SSRIs may be the most appropriate treatment option available.

Multiple studies have examined the effects of SSRIs on the developing fetus. Some data does show a link between these drugs and preterm birth, as well as low birth weight. However, depression during pregnancy is also linked to these effects, making it difficult to disentangle what's due to the drug and what's due to the illness.

SSRIs are linked to a condition called neonatal adaption syndrome, in which infants are born jittery, irritable and with abnormal muscle tone. About one-third of infants born to mothers taking SSRIs experience it. However, research shows that it usually resolves within two weeks and does not have long-term health implications.

The FDA-convened panel heavily focused on potential risks of SSRI usage, with several individuals incorrectly asserting that these drugs cause autism in exposed youth, as well as birth defects. At least one panelist discussed clinical depression as a "normal" part of the "emotional" experience during pregnancy and following birth. This perpetuates a long history of of women being dismissed, ignored and not believed in medical care. It also discounts the rigorous assessment and criteria that medical professionals use to diagnose reproductive mental health disorders.

A summary of the pivotal studies on SSRIs in pregnancy by the Massachusetts General Hospital Center for Women's Health discusses how research has shown SSRIs to not be associated with miscarriage, birth defects or developmental conditions in children, including autism spectrum disorder.

The risks of untreated mental illness

Untreated clinical depression in pregnancy has several known risks. As noted above, babies born to mothers with clinical depression have a higher risk of preterm birth and low birth weight.

They are also more likely to require neonatal intensive care and are at greater risk of behavioral problems and impaired cognition in childhood.

Women who are clinically depressed have an increased risk of developing preeclampsia — a condition involving high blood pressure that, if not identified and treated quickly, can be fatal to both mother and fetus. Just as concerning is the heightened risk of suicide in depression. Suicide accounts for about 8% of deaths in pregnancy and shortly after birth.

Compared with these very serious risks, the risks of using SSRIs in pregnancy turn out to be minimal. While women used to be encouraged to stop taking SSRIs during pregnancy to avoid some of these risks, this is no longer recommended, as it exposes women to a high chance of depression relapse. The American College of Obstetricians and Gynecologists recommends that all perinatal mental health treatments, including SSRIs, continue to be available.

Many women are already reluctant to take antidepressants during pregnancy, and given the choice, they tend to avoid it. From a psychological standpoint, exposing their fetus to the side effects of antidepressant medications is one of many common reasons for women in the U.S. to feel maternal guilt or shame. However, the available data suggests such guilt is not warranted.

Taken together, the best thing one can do for pregnant women and their babies is not to avoid prescribing these drugs when needed, but to take every measure possible to promote health: optimal prenatal care, and the combination of medications with psychotherapy, as well as other evidence-based treatments such as bright light therapy, exercise and adequate nutrition.

The panel failed to address the latest neuroscience behind depression, how antidepressants work in the brain and the biological rationale for why doctors use them in the first place. Patients deserve education on what's happening in their brain, and how a drug like an SSRI might work to help.

Depression during pregnancy and in the months following birth is a serious barrier to brain health for mothers. SSRIs are one way of promoting healthy brain changes so that mothers can thrive both short- and long-term.

Should the FDA, as a result of this recent panel, decide to place a black-box warning on antidepressants in pregnancy, researchers like us already know from history what will happen. In 2004, the FDA placed a warning on antidepressants describing potential suicidal ideation and behavior in young people.

In the following years, antidepressant-prescribing decreased, while the consequences of mental illness increased. And it's easy to imagine a similar pattern in pregnant women.

This edited article is republished from The Conversation under a Creative Commons license. Read the original article.

While there has long been broad scientific consensus that vaccines prevent or mitigate the spread of infections, there is new research suggesting that the therapeutic impact might go beyond the benefit of preventing infectious diseases.

An April 2025 study published in the prominent journal Nature found tantalizing evidence that the herpes zoster — or shingles — vaccine could lower the risk of dementia in the general population by as much as 20%.

We are a team of physician scientists with expertise in the clinical and basic science of neurodegenerative disorders and dementia.

We believe that this study potentially opens the door to other breakthroughs in understanding and treating dementia and other degenerative disorders of the brain.

A role for vaccines in reducing dementia risk?

One of the major challenges researchers face when trying to study the effects of vaccines is finding an unvaccinated "control group" for comparison — a group that is similar to the vaccine group in all respects, save for the fact that they haven't received the active vaccine. That's because it's unethical to assign some patients to the control group and deprive them of vaccine protection against a disease such as shingles.

The Nature study took advantage of a policy change in Wales that went into effect in 2013, stating that people born on or after September 2, 1933, were eligible for the herpes zoster vaccination for at least a year, while those born before that cutoff date were not. The vaccine was administered to prevent shingles, a painful condition caused by the same virus that causes chickenpox, which can lie dormant in the body and be reactivated later in life.

Related: Shingles vaccine may directly guard against dementia, study hints

The researchers used the policy change as a natural laboratory of sorts to study the effect of shingles vaccination on long-term health outcomes. In a statistically sophisticated analysis of health records, the team found that the vaccine reduced the probability of getting dementia by one-fifth over a seven-year period. This means that people who received the shingles vaccine were less likely to develop clinical dementia over the seven-year follow-up period, and women benefited more than men.

The study design allowed researchers to compare two groups without actively depriving any one group of access to vaccination. The two groups were also of comparable age and had similar medical comorbidities — meaning similar rates of other medical conditions such as diabetes or high blood pressure.

Results from this and other related studies raise the possibility that vaccines may have a broader role in experimental therapeutics outside the realm of infectious diseases.

These studies also raise provocative questions about how vaccines work and how our immune system can potentially prevent dementia.

How vaccines might be protective

One scientific explanation for the reduction of dementia by the herpes zoster vaccine could be the direct protection against the shingles virus, which may play a role in exacerbating dementia.

However, there is also the possibility that the vaccine may have conferred protection by activating the immune system and providing "trained immunity," in which the immune system is strengthened by repeated exposure to vaccines or viruses.

The study did not differentiate between different types of dementia, such as dementia due to Alzheimer's disease or dementia due to stroke. Additionally, researchers cannot draw any definitive conclusions about possible mechanisms for how the vaccines could be protective from an analysis of health records alone.

The next step would be a prospective, randomized, double-blind, placebo-controlled study — the "gold standard" for clinical trials in medicine — to directly examine how the herpes zoster vaccine compares with a placebo in their ability to reduce the risk of dementia over time. Such studies are necessary before any vaccines, as well as other potential therapies, can be recommended for routine clinical use in the prevention of dementia.

The challenges of untangling dementia

Dementia is a major noncommunicable disease that is a leading cause of death around the world.

A January 2025 study provided updated figures on lifetime dementia risk across different subsets of the U.S. population. The researchers estimate that the lifetime risk of dementia after age 55 is 42% — more than double earlier estimates. The dementia risk was 4% by age 75, and 20% by age 85, with the majority of risk occurring after 85. The researchers projected that the number of new cases of dementia in the U.S. would double over the next four decades from approximately 514,000 cases in 2020 to 1 million in 2060.

Once considered a disease largely confined to the developed world, the deleterious effects of dementia are now apparent throughout the globe, as life expectancy increases in many formerly developing countries. While there are different forms of dementia with varying clinical manifestations and underlying neurobiology, Alzheimer's disease is the most common.

Prospective studies that specifically test how giving a vaccine changes the risk for future dementia may benefit from studying patient populations with specific types of dementia because each version of dementia might require distinct treatments.

Unfortunately, for the past two to three decades, the amyloid hypothesis of Alzheimer's disease — which posits that accumulation of a protein called amyloid in the brain contributes to the disorder — dominated the scientific conversation. As a result, most of the efforts in the experimental therapeutics of Alzheimer's disease have focused on drugs that lower the levels of amyloid in the brain.

However, results to date have been modest and disappointing. The two recently approved amyloid-lowering therapies have only a minimal impact on slowing the decline, are expensive and have potentially serious side effects. And no drug currently approved by the Food and Drug Administration for clinical use reverses the cognitive decline.

Studies based on health records suggest that past exposure to viruses increase the risk of dementia, while routine vaccines, including those against tetanus, diphtheria, pertussis, pneumonia, shingles and others, reduce the risk.

Innovation and an open mind

There is sometimes a tendency among scientists to cling to older, familiar models of disease and a reluctance to move in more unconventional directions.

Yet the process of doing science has a way of teaching researchers like us humility, opening our minds to new information, learning from our mistakes and going where that data takes us in our quest for effective, lifesaving therapies.

Vaccines may be one of those paths less traveled. It is an exciting possibility that may open the door to other breakthroughs in understanding and treating degenerative disorders of the brain.

This edited article is republished from The Conversation under a Creative Commons license. Read the original article.

Hair can look different after chemotherapy, Tobin said. "In the vast majority of cases, post-treatment the hair regrows well and similar to the way it was before," he told Live Science. "But in the early stages of recovery, the hair texture and appearance may change."

The most commonly reported difference by patients who have completed chemotherapy is "chemo curls" — hair that regrows as curly when it had previously been straight. Usually, this changed hair returns to its original form within about a year, Tobin said. But why does hair grow back differently after chemotherapy?

To explain "chemo curls," first we need to understand how hair grows normally. Individual human hairs are long fibers of dead skin cells, composed mainly of keratin proteins, Sunny Wong, a professor of dermatology at the University of Michigan Medical School, told Live Science. Each strand is created by a hair follicle — a complex factory of different cell types — which passes through a constant cycle of growth, rest and shedding.

We're born with all of the hair follicles we will ever have, Tobin said. But a mixture of factors — including genetics, nutrition and fluctuating hormone levels during the different stages of life — means that the appearance of hair is constantly evolving.

Pigments control hair color: The production of sex hormones at the onset of puberty causes fair hair to darken, and pigment loss with age lightens hair to gray or white later in life.

Related: Can gray hair be reversed?

Meanwhile, the shape of the hair follicles determines the shape — and, therefore, texture — of each fiber, with circular follicles producing straight hair, flattened oval follicles creating coiled hair, and a follicle somewhere in between giving looser waves or curls.

How chemo changes hair

So what are chemotherapy drugs doing to these hair follicles? Cancer treatments target rapidly dividing cells so the hair follicles, which also contain stem cells to act as fuel for hair growth, are particularly vulnerable to damage.

"The hair follicle is one of the most proliferative and actively dividing tissues in the body, probably second to the bone marrow or gut, so it's preferentially attacked," Tobin said. "That causes the hair follicle to go into a hyper-stress response." Chemotherapy therefore halts the hair cycle, forcing these follicles to expel fibers during the growth stage or shift them into a dormant phase.

However, post-treatment, the stem cells within the individual hair follicles begin to wake up. The cycle gradually starts again, which enables the hair to regrow, but sometimes with a slightly altered appearance.

"The chemotherapeutic exposure will damage the existing hair follicle and may turn it into an abnormal shape so it produces a fiber of a different shape or length, maybe thinner," Tobin explained. "It depends on how that hair follicle copes with the impact of the drug."

Similarly, the effect of chemotherapy on other bodily systems — such as the endocrine system, which is responsible for making hormones — can temporarily alter the production of pigments, leading to a change in hair color.

Although the complexity of factors determining hair's appearance makes it difficult to predict an individual patient's response, in most cases, hair returns to normal as the body processes the remnants of the drug, Wong said.

"These drugs work by incorporating themselves into replicating DNA, so it takes time for them to elute from the system," Wong explained. "Probably the cells just need to build up over time and the signals [that regulate the hair cycle] just have to return and reconfigure."

The human body is remarkably resilient, and hair follicles damaged by cancer treatments can make a full recovery. Although it can be frustrating to wait for hair to return, experts urge patients to avoid damaging treatments like dyeing or straightening on their new growth.

"Hair typically grows a centimeter a month on the scalp, but good nutrition and blood supply will hopefully feed the soil in which those hair follicles are growing and improve its recovery," Tobin said.

As a pediatrician and researcher who studies vaccine delivery and health policy, I am hearing uncertainty from both parents and health care providers. If that describes you, you are not alone. A poll published Aug. 1, 2025, by the health policy organization KFF found half of parents are unsure whether federal health agencies are recommending COVID-19 vaccines for healthy children this fall.

The process that normally provides clear, consistent recommendations and ensures availability for vaccines before respiratory virus season has been upended, and this year's COVID-19 vaccine guidance for children is a prime example.

How the process typically works

For over two decades, there was a predictable, well-coordinated process to ensure recommended seasonal vaccines, such as the flu shot, were available for anyone who wanted them by early fall. In recent years, COVID-19 vaccines have been incorporated into this same annual cycle.

Beginning in February, the Food and Drug Administration, including its independent committee of experts, reviewed data and approved the optimal formulation. After FDA approval, the Advisory Committee on Immunization Practices, or ACIP, an independent panel of experts that advises the Centers for Disease Control and Prevention, reviewed the evidence in public meetings and issued clear recommendations.

The U.S. has long followed an established set of steps lining up vaccines for any given year.

Manufacturers then scaled up production; insurers confirmed coverage, which is tied to the advisory committee's recommendations; and doses were distributed nationwide so vaccines would be available in clinics and pharmacies before the leaves started turning. This usual series of steps ensured that guidance incorporated input from scientists, epidemiologists, public health experts, clinicians, manufacturers, insurers and consumers. It also fostered trust among health care providers and, in turn, provided parents with clarity and confidence when making decisions.

Related: 'These decisions were completely reckless': Funding cuts to mRNA vaccines will make America more vulnerable to pandemics

What's different this year

Since Robert F. Kennedy Jr. took over as secretary of Health and Human Services in February 2025, that usual, tightly choreographed dance has become a chaotic scramble marked by uncertainty and a lack of transparency. Decisions about vaccine guidance have been made through internal channels without the same level of public discussion, review of the evidence or broad stakeholder input.

In May 2025, Kennedy and FDA leadership bypassed the agency's independent review committee and announced that some COVID-19 vaccines would be approved only for children with high-risk conditions. One formulation has yet to be FDA-approved for children at all. The secretary first announced updated recommendations for children on X, stating COVID-19 vaccines would no longer be recommended for healthy children. Shortly after, the CDC posted guidelines that differed from that announcement and said healthy children "may" receive them. Meanwhile, the Advisory Committee on Immunization Practices was disbanded by Kennedy and replaced with a smaller, hand-picked panel that operates with less transparency and has yet to weigh in on COVID-19 vaccines for children.

Public messaging has added to the confusion. Statements from newly appointed federal health leaders have questioned the safety of COVID-19 vaccines and the long-standing processes for ensuring their safety. Funding for mRNA technology, which supports several COVID-19 vaccines and is being explored for use against other diseases and even some cancers, has been cut. And many of the claims used to justify these actions have been challenged by experts as inaccurate or misleading.

What this means for parents

For parents, the result is uncertainty about whether their children should be vaccinated, when and where the vaccines will be available, whether insurance will cover them, or whether their choice has effectively been made for them by newly appointed health leaders operating outside the guardrails of the normal vetting process. This uncertainty comes at a time when the uptake of COVID-19 vaccines in children is already lower than that of other routine vaccines.

Currently, CDC guidelines say healthy children six months and older "may" receive a COVID-19 vaccine based on shared decision-making with their health care provider. The CDC recommends that children who are moderately or severely immunocompromised receive it. These guidelines differ from FDA approvals and Kennedy's guidelines announced on X, and they have not been reviewed or voted on in an advisory committee on immunization practices meeting.

Parents can start by talking with their child's pediatrician about benefits and potential risks, confirming eligibility and checking on insurance coverage. Pediatricians welcome parents' questions and work tirelessly to provide answers grounded in the best available evidence so families can make truly informed decisions about their child's health.

In some cases, unfortunately, even if parents want the vaccine and their pediatrician agrees, they may not be able to get it due to any number of factors, including local supply shortages, lack of insurance coverage, policies that prevent administration by pharmacists and other health providers without clear federal guidance, or an unwillingness of providers to give it "off-label," meaning in a way that differs from the FDA's official approval. For those parents, their decision has been made for them.

Reducing risks in other ways

Whether or not a child receives an updated COVID-19 vaccine, parents can still take steps to reduce illness, including keeping children home when sick, teaching them cough-and-sneeze hygiene and encouraging frequent hand-washing. The CDC provides national and state data on seasonal respiratory illnesses, including COVID-19, while local public health websites often offer community-level information.

Parents should also remember that the COVID-19 vaccine is not the only thing to consider before school starts. Routine immunizations such as those for measles, mumps and rubella, known as the MMR vaccine; diphtheria, tetanus and pertussis, called DTaP; and influenza are essential for keeping kids healthy and in school. These are widely available for now. This is particularly important, as this year the United States has experienced the highest number of measles cases in decades.

Uncertainty surrounding COVID-19 vaccine recommendations, and potentially other vaccines, may worsen in the coming weeks and months. It is possible parents will continue to see shifting guidance, conflicting statements from federal agencies and reduced access to vaccines in their communities.

In this chaotic environment, parents can look to trusted sources such as their pediatrician or organizations such as the American Academy of Pediatrics, which will continue to provide independent, evidence-based vaccine guidance.

This edited article is republished from The Conversation under a Creative Commons license. Read the original article.

We have tried and tested multiple smart rings in relation to their design, features, tracking accuracy, battery life and other factors to give our verdict on their functionality and value for money. You can read more about our testing protocol in the How we test section, and if you are not sure if smart rings are right for you, scroll down to the FAQs section for more buying advice.

Smart rings do not tend to feature advanced motion sensors or GPS navigation, and as such, they may not be well-suited for tracking workouts. If logging exercise is your priority, consider investing in one of the best fitness trackers instead.

The quick list

The best smart rings we recommend in 2025

The best smart ring overall

The Oura Ring Gen 4 takes the well-deserved top spot. This smart ring is an excellent all-rounder, suitable for both beginners and seasoned fitness professionals, and it comes with the most inclusive size range and the longest battery life of all the models mentioned in this guide. More importantly, the Oura Ring Gen 4 offers accurate sleep and heart rate measurements, a good selection of health-tracking tools and personalized advice that is both detailed and easy to understand — all delivered in a beautifully designed and genuinely engaging app. We think it is the best choice for most people, even though it is not particularly comfortable to wear or budget-friendly.

This model is even better than the Oura Ring Gen 3, which we proudly proclaimed to be the best smart ring on the market for the last three years. While both versions offer largely the same features and tracking capabilities, the newer Gen 4 outperforms its older brother with a slimmer design and improved durability. It also feels somewhat more intuitive to use, but this is more likely down to the improvements in the app rather than the design of the ring itself.

Performance is the strongest aspect of the Oura Ring Gen 4. It has the longest battery life of all the smart rings we tested (approximately eight days), and its tracking accuracy is either comparable or better than of the Ultrahuman Ring AIR and Amazfit Helio mentioned below. During our full Oura Ring Gen 4 review, we were particularly impressed with its precise sleep quality assessments, and we can confidently say this smart ring is one of the best sleep trackers on the market.

However, it is now without its flaws. Yes, the Oura Ring Gen 4 is an accurate tracker, but this also means that it has big sensors that inevitably bulk it up. We found this smart ring somewhat uncomfortable to wear, and even after a week of testing, we still could not get used to its 'chunkiness' and heavy-ish weight. Moreover, we were disappointed by its overzealous automatic activity detection — the Oura Ring Gen 4 has a habit of overestimating how much of your daily activity constitutes actual exercise. Lastly, this smart ring needs a subscription for full access to the features.

• Full review coming soon

• Back to the top ⤴

Best subscription-free smart ring

If you do not want to be tied down with subscriptions, consider the Ultrahuman Ring AIR. This smart ring is a close match to the Oura Ring Gen 4 in terms of tracking accuracy, battery life and customization, and in some aspects, it even outperforms it — for example, the Ultrahuman Ring AIR is more comfortable to wear and comes with a more comprehensive selection of health-tracking features. True, its patchy app connectivity can be annoying at times and it can scratch easily when handling sharp objects, but you would be hard-pressed to find a better subscription-free alternative to the Oura Ring Gen 4.

It is a particularly good choice for fitness pros. While all the smart rings mentioned in this guide can help you improve your exercise performance, the Ultrahuman Ring AIR is the most data-heavy and comprehensive in its approach to fitness tracking. Not only is it jam-packed with graphs and numbers, but it can also help you optimize a wide range of lifestyle factors, such as your caffeine intake or sun exposure, and it can even track your blood sugar levels (that said, the Ultrahuman blood glucose sensors are sold separately). Hardly any fitness tracker we tested places so much emphasis on metabolism and circadian rhythm, and these two factors are important for rest and recovery.

Design also scored highly in our books. The Ultrahuman Ring AIR proudly proclaims to be "the world's most comfortable and compact smart ring" — and it rings true. It is the slimmest and lightest model of all the smart rings in this guide, and one that we enjoyed wearing the most. Not to mention, it simply looks good.

But, as we mentioned before, this smart ring is not without its flaws. During our full Ultrahuman Ring AIR review, we were particularly disappointed with its patchy app connectivity. While it worked fine most of the time, there were a significant number of times when we struggled to sync the data or even connect to the app. We could often resolve these issues by simply refreshing the app several times, but it can be annoying nevertheless.

Mixed durability was the other issue for us. While our Ultrahuman Ring AIR could easily sustain salt water, high temperatures and drops from height, it also seemed to scratch easily.

Lastly, its heart rate readings can become unreliable during high-intensity workouts — but then that is something we have seen in all the smart rings we tested.

Read more: Ultrahuman Ring AIR review

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Best budget smart ring

Smart rings are still a relatively new invention, and that is fully reflected in their price. Both the aforementioned Oura Ring Gen 4 and Ultrahuman Ring AIR are priced well above $300, placing them at the same level as some of the best Garmin watches, while many other popular smart rings — such as the RingConn Gen2 or Evie Ring, for example — typically cost more than $200. So, is it still possible to get a decent smart ring on a budget? Absolutely.

The Amazfit Helio costs $199 and we frequently see it on sale for less than $170, which is roughly half of what you would pay for the Oura Ring Gen 4. That is not even the best part. This smart ring is entirely subscription-free, making the Amazfit Helio one of the most affordable smart rings we tested. If our hands-on experiences are anything to go by, it is also one of the best-value models out there.

This budget smart ring nails the essentials. During our full Amazfit Helio smart ring review, we were impressed with its good tracking accuracy, high sensitivity to our fluctuating stress levels and the copious amounts of collected health data. At the same time, we liked that this smart ring does not overload you with numbers and complex terminology, and that it offers plenty of actionable, easy-to-understand health advice. The Amazfit Helio is a perfect option for fitness beginners, even more so than the Oura Ring Gen 4.

Secondly, the Amazfit Helio was very comfortable to wear. It was slim and light enough to make us forget we were even wearing it. This smart ring proved to be surprisingly durable, too. It sustained only one tiny scratch throughout two months of testing. All in all, the Amazfit Helio offers great value for money — as long as you look past some minor inconveniences.

This smart ring is available in three sizes only (8, 10 and 12) and it comes in just one color (light bronze), so it will not suit everyone. On top of that, the Amazfit Helio has a relatively short battery life. This smart ring lasts approximately three days on a single charge, so if you travel or go camping a lot, it may not be the best option for you.

Read more: Amazfit Helio smart ring review

• Back to the top ⤴

Best smart rings: comparison

Contributing experts & product testers

Best smart rings: Frequently Asked Questions

How to choose the best smart ring for you?

Our experts agree — there are many factors to look into when choosing a smart ring, but the most important ones are comfort, value for money and the quality of collected data. While it may be tempting to prioritize glitzy looks and advanced frills like multi-app connectivity, it is these three aspects that tend to have the biggest influence on your user experience.

"Choosing a ring starts with comfort," Rail said. Choosing the right size and fit will help you ensure that your ring suits you well, even when your fingers get slightly swollen. "Order the sizing kit, wear each plastic placeholder for an entire day, and notice whether the finger throbs at night," Rail said. Battery life is another important factor here. Four to seven days on a single charge are enough to provide consistent data without frequent charging breaks, Rail said.

Then, decide which measurements can help you make a tangible difference to your health and fitness. "Don’t get lost in the data — start with your goals," Cann said. "For example, ask yourself what you want to change or understand about your sleep, then pay attention to factors that will help you achieve those goals. In my clinical work, I predominantly focus on sleep timing, duration and consistency. Look for a device that offers accurate estimates of these metrics, and these are based on high-quality measurements of body temperature, movement, heart rate variability, and respiratory rate."

One thing you can largely ignore? Sleep stage tracking. "These estimates remain unreliable across all wearables and are not critical for most people looking to improve sleep," Cann told Live Science.

Lastly, weigh the functionality of a smart ring against its price and potential extra fees. Many models require a subscription to unlock all of its tracking tools and advanced features, while some other rings may be subscription-free, but only offer basic metrics. Your choice here will largely depend on your needs, goals and preferences, but it may be worth a try. "A few of my clients have reported that they cancelled the subscription after the first year and still felt satisfied with the core data. Decide whether you value deep coaching and monthly new features or prefer a simple dashboard that keeps running without another bill," Rail said.

That said, be mindful that information overload can lead to data-driven anxiety, Cann said. "Smart rings give you a helpful foundation, but it is what you do with that information that drives change. Use the data to guide actionable steps, like adjusting bedtime, improving wind-down routines, or tracking how stress affects your sleep. That’s how you turn metrics into real improvements," Cann concluded.

Latest updates

How we tested these smart rings

How we test the best smart rings

We are experienced fitness professionals and sports enthusiasts who have spent many years trying and testing activity trackers, including smart rings and other screenless devices. You can trust our judgments — we have a deep passion for wearable tech, use several different devices at a time, and are always on the lookout for the next big thing to help us achieve our health and fitness goals. We have first-hand knowledge as to what works and what does not live up to expectations.

That said, we also pride ourselves on being fair and objective in our reviews. All smart rings in this guide were tested to the exact same standard, using the same procedures. After spending at least a month or two with each testing unit, we ranked it across the following categories:

1) Design. We look into the size, weight and appearance of the smart ring in question. We assess whether it is comfortable to wear and sufficiently customizable (for example, we check how many colors and sizes it comes in), and try to gauge its durability based on the materials it is made of and any scuffs and scratches it may have sustained during testing.

2) Features. We give our verdict on its overall functionality. How many health metrics and activities does it track, and how detailed are these measurements? How many apps can this smart ring connect to? Can it explain your data and provide personalized health advice, and if so, is it actionable and easy to understand?

3) Performance. We put the smart ring through a range of activities to test its battery life, general tracking accuracy and app connectivity. We also assess the validity of its heart rate tracking features using either a chest-strap heart rate monitor (such as the Polar H9) or a medically graded fitness tracker like the Whoop MG.

Verdict. Finally, we try to answer the key questions: Who is this smart ring for? Should you buy it? If so, does it deliver good value for money? After testing, we calculate a final score out of five and explain our reasoning behind it.

But here's the kicker: There's a good chance you're not actually allergic to penicillin. About 10% to 20% of Americans report that they have a penicillin allergy, yet fewer than 1% actually do.

I'm a clinical associate professor of pharmacy specializing in infectious disease. I study antibiotics and drug allergies, including ways to determine whether people have penicillin allergies.

I know from my research that incorrectly being labeled as allergic to penicillin can prevent you from getting the most appropriate, safest treatment for an infection. It can also put you at an increased risk of antimicrobial resistance, which is when an antibiotic no longer works against bacteria.

The good news? It's gotten a lot easier in recent years to pin down the truth of the matter. More and more clinicians now recognize that many penicillin allergy labels are incorrect — and there are safe, simple ways to find out your actual allergy status.

A steadfast lifesaver

Penicillin, the first antibiotic drug, was discovered in 1928 when a physician named Alexander Fleming extracted it from a type of mold called penicillium. It became widely used to treat infections in the 1940s. Penicillin and closely related antibiotics such as amoxicillin and amoxicillin/clavulanate, which goes by the brand name Augmentin, are frequently prescribed to treat common infections such as ear infections, strep throat, urinary tract infections, pneumonia and dental infections.

Related: Mold that led to penicillin discovery revived to fight superbugs

Penicillin antibiotics are a class of narrow-spectrum antibiotics, which means they target specific types of bacteria. People who report having a penicillin allergy are more likely to receive broad-spectrum antibiotics. Broad-spectrum antibiotics kill many types of bacteria, including helpful ones, making it easier for resistant bacteria to survive and spread. This overuse speeds up the development of antibiotic resistance. Broad-spectrum antibiotics can also be less effective and are often costlier.

Why the mismatch?

People often get labeled as allergic to antibiotics as children when they have a reaction such as a rash after taking one. But skin rashes frequently occur alongside infections in childhood, with many viruses and infections actually causing rashes. If a child is taking an antibiotic at the time, they may be labeled as allergic even though the rash may have been caused by the illness itself.

Some side effects such as nausea, diarrhea or headaches can happen with antibiotics, but they don't always mean you are allergic. These common reactions usually go away on their own or can be managed. A doctor or pharmacist can talk to you about ways to reduce these side effects.

People also often assume penicillin allergies run in families, but having a relative with an allergy doesn't mean you're allergic — it's not hereditary.

Finally, about 80% of patients with a true penicillin allergy will lose the allergy after about 10 years. That means even if you used to be allergic to this antibiotic, you might not be anymore, depending on the timing of your reaction.

Why does it matter if I have a penicillin allergy?

Believing you're allergic to penicillin when you're not can negatively affect your health. For one thing, you are more likely to receive stronger, broad-spectrum antibiotics that aren't always the best fit and can have more side effects. You may also be more likely to get an infection after surgery and to spend longer in the hospital when hospitalized for an infection. What's more, your medical bills could end up higher due to using more expensive drugs.

Penicillin and its close cousins are often the best tools doctors have to treat many infections. If you're not truly allergic, figuring that out can open the door to safer, more effective and more affordable treatment options.

How can I tell if I am really allergic to penicillin?

Start by talking to a health care professional such as a doctor or pharmacist. Allergy symptoms can range from a mild, self-limiting rash to severe facial swelling and trouble breathing. A health care professional may ask you several questions about your allergies, such as what happened, how soon after starting the antibiotic did the reaction occur, whether treatment was needed, and whether you've taken similar medications since then.

These questions can help distinguish between a true allergy and a nonallergic reaction. In many cases, this interview is enough to determine you aren't allergic. But sometimes, further testing may be recommended.

One way to find out whether you're really allergic to penicillin is through penicillin skin testing, which includes tiny skin pricks and small injections under the skin. These tests use components related to penicillin to safely check for a true allergy. If skin testing doesn't cause a reaction, the next step is usually to take a small dose of amoxicillin while being monitored at your doctor's office, just to be sure it's safe.

A study published in 2023 showed that in many cases, skipping the skin test and going straight to the small test dose can also be a safe way to check for a true allergy. In this method, patients take a low dose of amoxicillin and are observed for about 30 minutes to see whether any reaction occurs.

With the right questions, testing and expertise, many people can safely reclaim penicillin as an option for treating common infections.

This edited article is republished from The Conversation under a Creative Commons license. Read the original article.

Being able to witness the complex implantation process may be helpful for advancing fertility procedures, such as in vitro fertilization (IVF), the researchers say.

"We have observed that human embryos burrow into the uterus, exerting considerable force during the process," study co-author Samuel Ojosnegros, principal investigator for the Bioengineering for Reproductive Health Group at the Institute for Bioengineering of Catalonia (IBEC) in Spain, said in a statement. "It is a surprisingly invasive process."

In a study published Friday (Aug. 15) in the journal Science Advances, the researchers detailed their invention of an apparatus that enabled them to record a video showing how human embryos implant. The process let them measure the force exerted during implantation and see how it differs between human and mouse embryos.

During implantation, mammalian embryos attach to the endometrium — the lining of the uterus — and then begin to develop and give rise to more and more cells. Sometimes, though, this biological process doesn't work as expected. "Implantation failure is one of the main causes of infertility, accounting for 60% of miscarriages," the researchers wrote in the study.

Studying how embryo implantation works in humans is difficult in part because it requires capturing a short moment in time inside a complex organ. Capturing that fleeting moment would be especially difficult inside a person — for instance, a patient undergoing IVF — given that it could be risky to disrupt the reproductive system at that time.

Related: Should we rethink our legal definition of a human embryo?

As such, the only footage of human implantation captured before the new study was a series of still images of embryos at specific moments in the process and in a simple laboratory model of the uterine environment.

Now, researchers at IBEC have developed a way to capture the implantation of a human embryo in four dimensions. First, they created a gel made of various proteins in uterine tissue, including collagen, and put early-stage embryos in the gel. The embryos used in this study were donated by couples undergoing IVF.

This setup enabled the team to use microscopy and fluorescence imaging techniques to record the embryos' implantation into the gel. When watching the implantations, they discovered that, after releasing enzymes that broke down the uterine tissue, the human embryo invaded the uterus.

"The embryo opens a path through this structure and begins to form specialised tissues that connect to the mother's blood vessels in order to feed," Ojosnegros said. (Research done by other labs has detailed how the placenta — the temporary organ that supplies oxygen and nutrients to the fetus — similarly invades a major maternal artery in order to form in early pregnancy.)

They also found that the burrowing embryo exerted force on the uterus, essentially moving and reorganizing the tissues. The embryos also appeared to respond to external forces that they encountered, such as the addition of other cells and structures into the goo. "We hypothesize that contractions occurring in vivo [in the body] may influence embryo implantation," study co-author Amélie Godeau, a researcher at IBEC, said in the statement.

These contractions may hold one key to successful implantation, the researchers suggested in the study. The human uterus spontaneously contracts one to two times per minute, on average, and the nature of these contractions changes throughout the menstrual cycle. A previous study found that people with too many or too few uterine contractions on the day of embryo transfer in IVF had lower implantation rates than people with a "just right" amount.

"This suggests that there may be an optimal frequency range favorable for embryo implantation," the researchers wrote. The exact role of uterine contractions in successful implantation is still being studied, though.

A better understanding of the complexity of the human uterus and the process of implantation may lead to better IVF outcomes in the future, the study authors proposed.

This article is for informational purposes only and is not meant to offer medical advice.

Get the Oral-B Genius X Limited electric toothbrush on sale right now for $79.99 at Amazon.

Right now at Amazon, the Oral-B Genius X Limited, our top choice in the Live Science best electric toothbrush buyers guide, has hit one of the cheapest prices we've ever seen at just $99.99. As an extra incentive, Amazon is also offering a bonus $20 coupon, which takes it down to a bargain $79.99, and an overall saving of $120.99.

The Oral-B Genius X secures the top position in our guide to the best electric toothbrushes, and it received an impressive 4.5 out of 5 from our tester, Joanne Lewsley. She felt the Genius X electric toothbrush outperformed its competitors with outstanding brushing performance, compact design, and a wide range of innovative smart features.

The Genius X also has over 8,500 reviews from Amazon shoppers and an average rating of 4.4 stars, so if you've been considering an electric toothbrush, then I'd suggest grabbing this, because you'll be hard pushed to find anything that comes close at this discounted price.

• We're constantly checking the best prices on our Amazon deals page, and you'll find big discounts on the best telescopes, binoculars, star projectors, cameras, fitness trackers, running shoes, rowing machines and more.

Some of the many impressive features that make this not only an outstanding electric toothbrush, but a brilliant piece of tech too, are the AI and the Oral-B app. The AI is claimed to have learned from thousands of human brushing behaviours and will recognize your brushing style.

It will track all your brushing movement patterns and habits, giving you real-time, simple and actionable prompts to follow — almost like having your dentist in your bathroom.

The Genius X Limited has built-in Bluetooth technology, allowing you to connect it to your smartphone and track all your brushing stats and performance on the interactive Oral-B app.

The Oral-B Genius X also comes with six cleaning modes, including one designed for sensitive teeth, while its gum pressure control feature will alert you if you brush too hard. There is also a 2-minute timer, and the powerful lithium-ion battery keeps it running for around 14 days on a single charge.

Key features: AI-powered tracking, personalized coaching, Bluetooth technology, six cleaning modes, pressure sensor, 14-day battery life, timer, travel case, charger, and one replacement brush head.

Product launched: October 2019.

Price history: The launch price of Oral-B Genius X Limited was $285, and although the $99.99 deal price has been seen before, with the additional $20 bonus discount, it takes it to the lowest price we've ever seen.

Price comparison: Walmart $169.99.

Reviews consensus: The Genius X has held the best overall crown in our best electric toothbrushes guide, and this premium electric toothbrush ticked all the boxes for its outstanding brushing performance and AI-powered assistance. It also has over 8,500 reviews from Amazon shoppers and an average rating of 4.4 stars, and Amazon reviewers like us loved its smart features, along with the travel-friendly package.

LiveScience: ★★★★½ | TechRadar: ★★★★

Featured in guides: Best electric toothbrushes.

✅ Buy it if: You want a thoughtfully designed toothbrush that is compact, stylish and packed with features, including AI, that will help you elevate your brushing performance.

❌ Don't buy it if: You want something ultra-quiet or a more basic offering. The Bitvae R2 is our best budget electric toothbrush, and currently discounted to just $29.99 on Amazon.

Check out our other guides to the best telescopes, binoculars, cameras, star projectors and much more.