Weight loss with GLP-1 medicines does not result in a disproportionate loss of muscle mass or function in obese mice and humans
Langer HT, et al. (2026). Cell Reports Medicine.
Summary
A paper combining four preclinical studies in obese mice with a proof-of-concept clinical trial of a GLP-1 medicine in adults with obesity. In the mice, weight loss was mostly fat, with a small fall in lean mass, and muscle was relatively larger compared with body weight even though absolute muscle mass fell. In the human trial, body composition improved without a negative effect on strength. GLP-1 treatment also produced protein-level changes in muscle that differed from calorie restriction alone. The abstract does not give human sample size; the mouse and human parts are different study designs and the human trial is small.