Ozempic and Wegovy: Scientists call for more research on GLP-1 receptor agonists and muscle loss

Medicines such as Ozempic and Wegovy are widely recognised for helping people lose weight, yet some scientists are pressing for clearer answers on what these drugs might mean for muscle loss.

In a fresh commentary in The Lancet, an international group of researchers cautions that evidence on how GLP-1 receptor agonists affect muscles is still too limited.

What researchers say about GLP-1 receptor agonists

The authors stress that GLP-1 agonists have "shown substantial benefits" for large numbers of people globally. Early research indicates that these medicines-initially authorised for treating type 2 diabetes-can also support weight loss.

They add that even people who do not lose weight may still see improvements in kidney and heart health, lowering their risk of stroke or cardiac arrest.

Concerns about muscle loss and fat-free tissue loss

Despite these positives, the team highlights preliminary findings suggesting that GLP-1 agonists are linked with slightly higher rates of non-fat tissue loss than weight loss achieved without medicines.

They note that losing fat-free tissue does not necessarily map directly onto muscle loss, and that a reduction in muscle mass is not automatically harmful for strength or mobility. However, dietitian Carla Prado, biomedical researchers Stuart Phillips and Steven Heymsfield, and nutritionist Cristina Gonzalez argue that stronger evidence is needed before anyone can be confident about the real-world implications.

"At the time of writing, there are no data to establish whether treatment with GLP-1 receptor agonists is associated with physical frailty or [a loss of muscle mass]," the team writes.

"These effects would require long-term studies, which are not yet available, and the studies conducted to date were not designed to answer these questions."

While early studies indicate that the weight loss associated with GLP-1 agonists does not reduce strength, the authors point out that strength "is only one aspect of muscles' importance."

Why muscles matter beyond movement

The commentary explains that muscles do more than drive movement: they are central to metabolism, immune function, and how the body responds to stress and trauma.

Muscle mass also supports the body’s uptake of glucose in response to insulin.

The researchers are concerned that, in some patients, any muscle loss could further worsen risk factors already associated with GLP-1 agonists, including metabolic dysfunction, inflammation, inadequate dietary intake, and low levels of physical activity.

Using Ozempic and Wegovy strategically: nutrition and exercise

Given these potential risks, the authors conclude that "these highly effective medications should be used strategically. This strategy can be accomplished with concurrent nutrition and exercise interventions."

Research suggests that after weight loss, declines in skeletal muscle mass can be partly moderated through higher protein intake or exercise. According to some estimates, resistance exercise can attenuate losses in fat-free mass by 50 to 95 percent.

These findings strengthen the case that exercise programmes and nutrition guidance should be recommended alongside GLP-1 agonists to achieve the best outcomes.

The authors also note that when people stop taking these appetite-suppressing medicines, they typically regain about two-thirds of the weight they lost within a year. In a recent clinical trial, however, participants in supervised exercise programmes were more successful at maintaining their weight loss.

"Additionally," the team writes, "ongoing studies are exploring ways to prevent or mitigate muscle loss with drugs… which could offer solutions for preserving muscle mass in individuals undergoing weight loss treatments."

The possibility of muscle loss is not, in their view, a reason for patients to stop taking GLP-1 agonists. But because muscles are so important to human health, they argue that more research is urgently needed.

The commentary was published in The Lancet: Diabetes & Endocrinology.