How much lean mass do people typically lose on GLP-1?

In published trials of semaglutide and tirzepatide, lean mass commonly accounts for a meaningful share of total weight lost, in some analyses up to roughly 40 percent without any intervention. The number varies by age, sex, training history, and protein intake. Older and sedentary people tend to lose a larger share as lean mass; younger adults who train and eat enough protein hold on to most of theirs. Trial averages do not have to be your story. Aiming for 1.2 to 1.6 grams of protein per kilogram per day, paired with two to four resistance sessions a week, is associated with a smaller lean-mass share in the research. A DEXA scan every 3 to 6 months is one way to see which side of the average you are on. This is general information, not medical advice.