Researchers found that weight loss from GLP-1 receptor agonists, like semaglutide and tirzepatide, results in a similar loss of lean mass as traditional caloric restriction. This includes muscle, but the impact on overall strength appears minimal. While these drugs can lead to significant weight loss—15-20% of body weight over several months—about a quarter of that weight loss can come from lean mass, which includes muscles as well as organs and tissues.

For people looking to maintain muscle strength and overall health while losing weight, this finding is important. If you’re using GLP-1 drugs to manage obesity, you might be concerned about losing muscle along with fat. However, studies indicate that the muscle loss associated with these medications does not significantly impair strength or function, meaning you can still maintain an active lifestyle even while losing weight.

The research involved both animal studies and a small human trial. In mice, the weight loss from GLP-1 drugs resulted in about 20% of the loss coming from lean mass, similar to what happens with regular dieting. In a small human study of ten people with obesity and type 2 diabetes, participants experienced a significant reduction in body weight and fat, but muscle strength remained unchanged. This suggests that while GLP-1 drugs may lead to some muscle loss, it is comparable to natural weight loss and does not necessarily translate to decreased strength or mobility.

If you’re considering GLP-1 medications, it may be wise to combine them with strength training or resistance exercises, as these can help preserve muscle mass. Always consult with a healthcare professional before starting any new treatment or exercise program.

Source: lifespan.io