Assessing Heart Risks: The Long-Term Effects of Ozempic and Wegovy on Muscle Health

Popular weight loss drugs like Ozempic and Wegovy show strong short-term benefits. These include improved metabolic health, pain relief, help with addiction, and better cognitive health. However, long-term side effects are still emerging.

Experts have raised concerns that these weight loss drugs, called GLP-1 receptor agonists, may lead to muscle loss along with fat loss. More research is needed to fully understand these effects.

Researchers from the University of Alberta in Canada investigated how GLP-1 drugs affect cardiac muscle. They administered semaglutide, the active ingredient in Ozempic, to lean and obese mice for 21 days. Neither group had diabetes or heart problems.

The obese mice lost about 30% of their body weight and 65% of their fat mass. In lean mice treated with semaglutide, researchers observed an 8% reduction in skeletal muscle over three weeks.

Both groups of treated mice experienced a decrease in overall heart mass and the size of heart muscle cells, but heart function remained unchanged. The authors noted that cardiac shrinkage from semaglutide happens regardless of weight loss.

The researchers also treated human cardiac muscle cells with semaglutide in the lab. These cells showed significant reductions in size. The authors speculate that semaglutide could cause cardiac atrophy, but they do not observe clear symptoms of this condition.

The findings suggest that semaglutide might harm heart muscles in the long run. If these results apply to humans, individuals with existing heart disease could be at higher risk if they take semaglutide or similar drugs.

It is still unclear if diet or exercise can counteract potential heart muscle loss. Future studies should focus on this aspect, similar to ongoing research on skeletal muscle loss.

The researchers recommend thorough evaluation of heart structure and function in clinical studies involving GLP-1 agonists. Another paper by the American Heart Association calls for a more complete assessment of these drugs on muscle health, particularly as many patients may use them long-term.

This study appeared in The Lancet.