Metabolic HealthGLP-1 Drugs and Muscle Loss: What the New Data Actually Shows
In this AMA episode, Peter Attia digs into the growing body of evidence on GLP-1 receptor agonists — drugs like semaglutide and tirzepatide — and their effects on lean mass, bone density, and physical function. He challenges early fears about muscle loss, explaining why DEXA scans can give misleading readings and why strength and function often improve even when lean mass appears to drop. Peter compares outcomes across drugs and against bariatric surgery, identifies who is most at risk for meaningful muscle loss, and offers concrete strategies around resistance training and protein intake. He also previews early data on retatrutide, a next-generation triple-hormone therapy, and cautions against using gray-market versions before FDA approval.
