A new study reveals that the Ozempic could weaken muscle strength, even if your muscles do not seem to decrease in size. Results observed in animals which remain to be confirmed in humans.
Less severe loss of muscle mass than expected
For several months, the Ozempic, a semaglutide -based drug initially designed for type 2 diabetes, has been massively diverted worldwide to induce weight loss. One of the ongoing debates concerns the lean mass: what do we really lose when we lose weight thanks to the Ozempic? Does this drug also reduces muscle mass?
The team of Katsu Funai, associate professor of medicine at the University of Utah, looked at this issue through a study conducted on model mice. Verdict: the loss of total lean mass reached around 10 %, but the skeletal muscles only represented a minor part of this decline.
The researcher RAN HEE CHOI, PHD, the first author of the study, specifies: “Our data suggest that the majority of lean mass loss is not due to muscle cast. For example, we have observed a significant reduction in liver size“.
More specifically, the mass of the liver had halved. This phenomenon could be interpreted positively, because in cases of obesity, this organ often accumulates large amounts of fat. “”These reductions can be considered as part of healthy weight loss“, Continues Choi.
Weakened muscles … even without change in volume
But beyond the mass, it was the muscular function that alerted the researchers. By testing several muscle groups, they observed that muscular strength decreased as the mice lost weight, even when the size of the muscle remained significantly the same. For other muscles, the force remained unchanged. It is unclear how weight loss drugs affect this balance in humans, specify researchers.
These data suggest a potentially complex effect of semaglutide on physical performance. This dissociation between volume and strength challenges researchers, because it could have gone unnoticed in studies centered solely on body composition.
The possible decrease in force due to the use of Ozempic could be particularly worrying for people over the age of 60, as they are already more likely to undergo muscle loss and a reduction in their mobility. Katsu Funai insists: “The loss of physical function is a very powerful indicator not only of the quality of life, but also of longevity“.
Why this loss of strength worries researchers
If muscle mass remains generally preserved, the weakening of certain muscle groups asks serious questions about the prolonged use of the semaglutide. In a context of aging or sedentary lifestyle, this functional drop could amplify the risks of fall, loss of autonomy or fragility. The effects seem to vary according to the targeted muscles.
The researchers point out, however, that these conclusions come from an animal model. To learn from it generalizable to humans, rigorous clinical trials are necessary. “”There remains an important need for validation in humans, especially with regard to muscle strength “says Karasawa.
Funai adds that clinical trials should assess the evolution of muscle strength, not only for Ozempic, but also for future weight loss drugs. “”Many other weight loss drugs are currently on clinical trials and will be marketed in the next three to five years (…) but with all these clinical trials, if you want to measure the loss of lean mass, you have to take into account physical function “.
The study recalls a fundamental principle too often neglected in the universe of medical “Weight Loss”: weight loss does not always rhyme with health gain. The authors call for a paradigm shift: measuring metabolic health can no longer be limited to the balance or the BMI.