# Mounjaro Causes Greater Muscle Loss Than Ozempic
Mounjaro users lose more lean body mass than those taking Ozempic, according to clinical data. Both drugs belong to the GLP-1 class of medications that suppress appetite and lower blood sugar, but they work through different mechanisms.
Mounjaro contains tirzepatide, which targets two hormone receptors in the body. Ozempic contains semaglutide, which targets one receptor. This dual-action approach in Mounjaro produces faster weight loss overall, but that comes with a tradeoff. People lose a higher percentage of muscle alongside fat.
Lean body mass includes muscle, bone, and organ tissue. Preserving it matters because muscle burns more calories at rest and supports metabolic health. Rapid weight loss from any drug risks muscle breakdown if people don't exercise and eat enough protein.
The research shows Mounjaro users lost roughly 35 to 40 percent of their weight as muscle, compared to 25 to 30 percent for Ozempic users. Experts recommend resistance training and adequate protein intake while taking either medication to minimize muscle loss.
Neither drug is a standalone solution. Diet and exercise remain essential to preserve body composition during weight loss treatment.