Research Suggests Ozempic May Reduce Muscle Strength Despite Stable Muscle Size

As the use of Ozempic, a widely prescribed medication for diabetes management and weight loss, continues to increase, researchers are scrutinizing its potential side effects, particularly its impact on muscle health. Recent studies indicate that while the drug may not significantly decrease muscle mass, it could still lead to a decline in muscle strength, raising concerns about its effects on physical function.

A new investigation conducted on mice suggests that although muscle size remains relatively stable during Ozempic treatment, muscle strength may diminish. The study highlights that muscle mass changes are less than initially expected, but muscles may still weaken, emphasizing the necessity for clinical research to fully understand these effects. Associate Professor Katsu Funai from the University of Utah notes that current data from animal models point to complexities that are not yet fully understood.

The study reports that Ozempic-related weight loss results in about a 10% decrease in lean body mass. Interestingly, most of this loss is attributed not to skeletal muscle but to reductions in other organs like the liver, which shrank by nearly half. While loss of organ mass during weight loss can be normal, especially in metabolically active tissues, the researchers stress that further investigation is needed to determine if similar organ changes occur in humans and if they pose health risks.

Additionally, the research found that some skeletal muscles did shrink slightly, by around 6%, but others remained unchanged. The decrease in muscle strength was observed even when muscle size did not change, indicating a disconnect between muscle volume and functional capacity. This phenomenon is concerning, particularly for adults over 60, as muscle strength directly correlates with mobility and longevity.

Despite these findings, the researchers caution against directly applying results from mice to humans, since weight gain and loss behaviors differ between species. Mice tend to overeat when fed a high-fat diet, whereas weight gain in humans involves multiple factors such as genetics and lifestyle. Therefore, the study underscores the urgent need for well-designed clinical trials to assess muscle effects—specifically strength—in humans using Ozempic and similar medications.

Future research should incorporate measurements of physical function to ensure comprehensive understanding of how weight-loss drugs influence muscle health. As Dr. Funai states, "Our findings are preliminary, and human data are essential to confirm these observations." The goal is to optimize weight management treatments without compromising muscle health and mobility.

For more details, see the published study in Cell Metabolism: DOI: 10.1016/j.cmet.2025.07.004. Source: MedicalXpress.