“up to 40 per cent of the weight lost by people using weight-loss drugs is actually muscle.”
Semaglutide shrank heart muscle in obese and lean mice, and the effect held in cultured human heart cells. A Lancet commentary puts muscle at up to 40 percent of the weight lost on these drugs, far above dieting or normal aging. Lead author Jason Dyck wants cardiac structure checked in existing trials. The people taking it off-label for a smaller waist are the trial nobody is running.