Without specific intervention, between roughly a quarter and forty-five percent of weight lost on a GLP-1 receptor agonist can be lean tissue rather than fat — depending on the drug, the dose, and the trial.[1][2][3] With adequate protein intake (1.2 g/kg/day or above) and a resistance-training stimulus, that share drops substantially.[8][9] This article walks through what the published trial substudies actually report, why the figure varies, and what changes it.