Not all of it is fat
The medication is working. The scale is moving. But not all of what comes off is fat.
Across the large semaglutide and tirzepatide trials, roughly a quarter to a little under half of the weight lost on a GLP-1 is lean tissue: muscle and bone, not fat. For most people that share sits around 25 to 40 percent. The drug does not distinguish between the tissue you want gone and the tissue that carries you up stairs at sixty. Muscle is the body's largest metabolic organ and the single clearest marker of how independently a person ages. Lose it quietly now, and the version of you on the other side of the medication is lighter, but weaker, slower to recover, and harder to rebuild.

