Adding a Muscle Targeting Antibody to Semaglutide Cut Lean Mass Loss from 7.4% to 2.9% in a Phase 2 Trial

Adults taking semaglutide alone lost 7.4 percent of their lean mass over the course of a phase 2 trial. Adults taking semaglutide plus an experimental antibody called bimagrumab lost 2.9 percent, while losing more total weight.

That contrast, from a trial published in Nature Medicine, addresses the most persistent clinical worry about GLP-1 drugs: that a meaningful share of the weight coming off is muscle rather than fat. Up to 40 percent of weight lost on these therapies may come from lean tissue.