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The Hill
4 days ago
- Health
- The Hill
Semaglutides may shrink muscle size, strength: Study
New research suggests popular weight loss drugs like Ozempic and Wegovy may affect more than just fat, raising questions about muscle strength and organ size after significant weight loss. University of Utah scientists studied semaglutide, the active ingredient in weight loss medications, in mice. In the study, published in the journal Cell Metabolism, researchers revealed 'unexpected effects,' highlighting that lean mass, or body weight that isn't fat, dropped about 10 percent. Most of the loss came from non-muscle tissues, particularly the liver, which shrank by nearly half. Some skeletal muscles lost around 6 percent of their size, while others remained unchanged. Despite relatively small changes in muscle size, certain muscles became weaker. Researchers said this could be especially concerning for adults over 60, who already face higher risks of muscle loss and reduced mobility. 'The loss of physical function is a strong predictor of not just quality of life but longevity,' said Katsu Funai, the senior author on the study. The findings challenge the assumption that lean mass loss comes mainly from skeletal muscle. Instead, they point to changes in metabolically active organs, such as the liver, which can shrink during healthy weight loss without harming function. 'It's unlikely that the observed lean mass loss represents a serious adverse effect,' said Takuya Karasawa, co-first author on the study. Still, scientists emphasize that further human studies are necessary to determine whether similar effects occur in humans and whether they pose health risks. 'There remains a significant need for validation in humans, especially concerning muscle strength,' Karasawa said. They also suggest that future clinical trials should track not only lean mass but also muscle strength and physical function, especially as more weight loss drugs enter the market. 'There are many additional weight loss drugs that are in clinical trials and coming out in the next three to five years,' Funai said. 'But with all those clinical trials, if they're interested in measuring lean mass loss, they need to consider physical function.'
Yahoo
6 days ago
- Health
- Yahoo
What effect does Ozempic have on muscles?
Mice aren't people, but they have a lot in common with humans genetically. And the furry rodents are often used in preliminary studies to help answer questions about where human research should go. For University of Utah researchers, a recently completed mouse study published in the journal Cell Metabolism suggests the need to look more closely at whether the popular drug Ozempic and other semaglutide drugs could cause muscle weakness that needs to be addressed for those taking the medications to manage diabetes or lose weight. The researchers hail the medications as a 'significant breakthrough in pharmacological interventions to treat obesity.' But they note recent concerns that Ozempic and similar drugs cause 'a loss of lean mass, potentially compromising physical function and quality of life, particularly in those susceptible to sarcopenia.' Sarcopenia is the loss of muscle mass, strength and function associated with age. But there are also medical conditions that could lead to worries about weakened muscles, too, the study's senior author, Katsu Funai, an associate professor of nutrition and integrative physiology at the University of Utah College of Health, told Deseret News. The goal is not to downplay the importance of how Ozempic and related drugs can improve health by controlling blood sugar or causing weight loss, he added. But his team wants to point out that measures might be needed to protect against a potential negative side effect. If further study shows that a drug leads to weaker muscles — especially in a population that might be susceptible already to losing strength — then those folks might need tandem interventions that maintain or build muscle strength. Funai said that besides age, recent surgeries, disabilities and other conditions might increase the risk of losing muscle strength. And quality of life is very much affected by muscle loss, which can lead to falls, injuries and inactivity, impacting overall health and well-being. What the Ozempic study found It's generally assumed that loss of lean muscle leads to loss of muscle mass and weaker muscles. That may not be as straightforward as some believe. The university-led research found those losing weight with Ozempic also lost about 10% of lean mass, though not necessarily from skeletal muscles, but from tissue such as the liver, which shrank a lot. 'Loss of mass in metabolically active organs, such as the liver, is expected as part of healthy weight loss,' Ran Hee Choi, research instructor in nutrition and integrative physiology at University Health and co-first author on the study, said in a news release. But both mice and humans can see organ size change alongside weight without a similar change in function. 'It's unlikely that the observed lean mass loss represents a serious adverse effect,' said Takuya Karasawa, postdoctoral researcher in the University of Utah Molecular Medicine Program and co-first author on the study. But size of muscles and strength are very different things, Funai said. And loss of lean mass is not the same as muscle loss or its strength, either. The researchers found that even when a muscle stayed the same size, it in some cases lost strength, while in other muscles that didn't happen. What isn't known — and needs to be studied, Funai said — is whether weight loss can lead to loss of muscle strength in some people and, if so, who would be impacted. Funai emphasized again that their work in mice raises questions, but does not necessarily apply directly to humans. For one thing, as the study notes, rodents and people gain and lose weight differently. People with obesity are often less physically active, while having obesity doesn't usually make mice more sedentary. And the mice were given obesity through a high-fat diet for the study, while people have many different reasons for weight gain, including genetics, diet, sleep patterns and age. Funai said it is very common for people to not realize they have lost strength in their muscles, but when it's tested, the loss is clear. 'When they're opening a jar or when they have to do flights of stairs that they don't usually do or have to carry something, then they might notice. It's something that they may not be aware of' otherwise, he said. He added that the loss of muscle mass and loss of muscle strength were dose dependent and time dependent, meaning that how long and how much Ozempic was given mattered. And the dose that was higher and where loss was more sustained was higher than would be given to people. It was noteworthy that loss of muscle mass and loss of force or strength weren't always coupled and that fact was not uncommon. The study points out the need for clinical trials that directly look at whether muscle strength is lost and if so, in which populations, Funai said. And those studies should consider not just Ozempic and other semaglutide weight-loss drugs, but those in development, he added. While studies frequently consider lean mass loss, physical function is an important issue that may not be so straightforward, he said. But it's critically important for those who may be vulnerable to losing strength and gaining associated risks. Solve the daily Crossword
Yahoo
05-08-2025
- Health
- Yahoo
Experts reveal potential unintended side effect of Ozempic – and whether we should worry
The use of weight-loss jabs in the UK has skyrocketed, with an estimated 1.5 million people using them. Yet drugs like Ozempic and Wegovy don't just help people lose fat, but potentially muscle too, new research has suggested. A study that tested weight loss jabs on mice found that although muscle mass changes less than expected, muscles still get weaker and tissues like the liver also shrink. Weight-loss injections, also known as GLP-1 receptor agonists, work by mimicking the natural hormone which regulates blood sugar, appetite and digestion. The medications, known as semaglutides, predominantly treat diabetes but are also available on the NHS or via private providers to help adults with a high body mass index (BMI). For example, although Ozempic is used for type 2 diabetes, it is sometimes prescribed off-label as a weight-loss drug. The results of the study, published in the journal Cell Metabolism, revealed Ozempic-induced weight loss decreased muscle mass by about 10 per cent. Most of this lost weight wasn't from skeletal muscles, which surround bones and joints, but instead from other tissues like the liver, which shrank by nearly half. However, because the Ozempic was tested on mice, researchers emphasise that more research is needed to determine whether similar changes to organ size occur in humans and whether those changes come with any risks. 'Loss of mass in metabolically active organs, such as the liver, is expected as part of healthy weight loss,' said Dr Ran Hee Choi, research instructor in nutrition and integrative physiology at the University of Utah college of health, and co-first author on the study. In both mice and humans, weight gain and loss can affect the size of organs like the liver without affecting their function. 'It's unlikely that the observed lean mass loss represents a serious adverse effect,' added Dr Takuya Karasawa, another co-first author on the study. Researchers found some skeletal muscles did shrink by about 6 per cent as the mice lost weight, but not enough to explain the overall muscle loss. However, when someone gains fat, they also tend to gain skeletal muscle. Study authors explain this is because the body needs to work harder to move around. As a result, losing extra fat can lead to a loss of muscle, which will not affect the person's overall quality of life. Researchers also tested the amount of force the mice's muscles exerted and found that some muscle strength decreased as the mice lost weight, even when the size of the muscle stayed roughly the same. This potential loss of strength when taking Ozempic could be a particular concern for adults over the age of 60 who are at a higher risk of muscle loss and reduced mobility. 'The loss of physical function is a strong predictor of not just quality of life but longevity,' added Dr Katsu Funai, professor of nutrition at the University of Utah and the senior author on the study. Dr Funai concluded that further clinical trials of weight loss jabs should check for changes in muscle strength. A spokesperson for Novo Nordisk, which makes Ozempic, said: 'In clinical trial for Wegovy or Ozempic we did not specifically study the medicine's impact on muscle mass. In a sub-study of 140 patients with a BMI of 40 or less, analysis suggested that treatment with Wegovy was accompanied by reductions in both fat and lean body mass, with a greater reduction in fat mass than lean body mass. 'We recommend that any patients experiencing side effects while taking Wegovy or Ozempic contact their healthcare provider.'
The Independent
05-08-2025
- Health
- The Independent
Experts reveal potential unintended side effect of Ozempic – and whether we should worry
The use of weight-loss jabs in the UK has skyrocketed, with an estimated 1.5 million people using them. Yet drugs like Ozempic and Wegovy don't just help people lose fat, but potentially muscle too, new research has suggested. A study that tested weight loss jabs on mice found that although muscle mass changes less than expected, muscles still get weaker and tissues like the liver also shrink. Weight-loss injections, also known as GLP-1 receptor agonists, work by mimicking the natural hormone which regulates blood sugar, appetite and digestion. The medications, known as semaglutides, predominantly treat diabetes but are also available on the NHS or via private providers to help adults with a high body mass index (BMI). For example, although Ozempic is used for type 2 diabetes, it is sometimes prescribed off-label as a weight-loss drug. The results of the study, published in the journal Cell Metabolism, revealed Ozempic -induced weight loss decreased muscle mass by about 10 per cent. Most of this lost weight wasn't from skeletal muscles, which surround bones and joints, but instead from other tissues like the liver, which shrank by nearly half. However, because the Ozempic was tested on mice, researchers emphasise that more research is needed to determine whether similar changes to organ size occur in humans and whether those changes come with any risks. 'Loss of mass in metabolically active organs, such as the liver, is expected as part of healthy weight loss,' said Dr Ran Hee Choi, research instructor in nutrition and integrative physiology at the University of Utah college of health, and co-first author on the study. In both mice and humans, weight gain and loss can affect the size of organs like the liver without affecting their function. 'It's unlikely that the observed lean mass loss represents a serious adverse effect,' added Dr Takuya Karasawa, another co-first author on the study. Researchers found some skeletal muscles did shrink by about 6 per cent as the mice lost weight, but not enough to explain the overall muscle loss. However, when someone gains fat, they also tend to gain skeletal muscle. Study authors explain this is because the body needs to work harder to move around. As a result, losing extra fat can lead to a loss of muscle, which will not affect the person's overall quality of life. Researchers also tested the amount of force the mice's muscles exerted and found that some muscle strength decreased as the mice lost weight, even when the size of the muscle stayed roughly the same. This potential loss of strength when taking Ozempic could be a particular concern for adults over the age of 60 who are at a higher risk of muscle loss and reduced mobility. 'The loss of physical function is a strong predictor of not just quality of life but longevity,' added Dr Katsu Funai, professor of nutrition at the University of Utah and the senior author on the study. Dr Funai concluded that further clinical trials of weight loss jabs should check for changes in muscle strength. A spokesperson for Novo Nordisk, which makes Ozempic, said: 'In clinical trial for Wegovy or Ozempic we did not specifically study the medicine's impact on muscle mass. In a sub-study of 140 patients with a BMI of 40 or less, analysis suggested that treatment with Wegovy was accompanied by reductions in both fat and lean body mass, with a greater reduction in fat mass than lean body mass. 'We recommend that any patients experiencing side effects while taking Wegovy or Ozempic contact their healthcare provider.'
South China Morning Post
26-05-2025
- Health
- South China Morning Post
Sleep helps the brain enter repair mode to clean up free radicals, Chinese study finds
Sleep serves as the brain's nightly clean-up crew, flushing out harmful oxygen-derived free radicals that accumulate during wakefulness, Chinese scientists have discovered in a landmark study. The research published in Cell Metabolism on May 15 deciphers how hydrogen peroxide (H₂O₂), a reactive by-product of metabolism, acts as a molecular signal to trigger sleep and restore balance in the brain. By confirming a decades-old hypothesis, the team found that when H₂O₂ levels rise in sleep-regulating neurons, the brain switches to 'repair mode,' prompting restorative slumber. 06:23 Can China claim the leadership mantle after the US quits the WHO and Paris Agreement? Can China claim the leadership mantle after the US quits the WHO and Paris Agreement? Excess build-up of these free radicals disrupts sleep quality and sparks inflammation, offering critical insights into age-related insomnia and degenerative diseases such as Alzheimer's disease This breakthrough not only solves a long-standing mystery of why sleep is biologically essential but also opens pathways for therapies targeting oxidative stress to combat sleep disorders. While scientists around the globe have identified some molecular changes that occur in the brain during sleep, Liu Danqian, a researcher from the Shanghai-based Centre for Excellence in Brain Science and Intelligence Technology, an affiliate of the Chinese Academy of Sciences, who led the study, said this was 'the first time' they had fully delineated how a molecule specifically functioned in the brain. Just as a person seeks food when they are hungry or water when they are thirsty, this type of instinctive behaviour is known in neuroscience as 'homeostatic regulation' – the body's ability to maintain a stable internal environment. One mystery scientists have been exploring is what kinds of material changes in the brain trigger homeostatic regulation of sleep, according to Liu.
