Do you lose muscle on Ozempic (GLP-1s) — and how do you prevent it?

Muscle loss is the single most consensus-rich concern about GLP-1 drugs across the panel — and the good news is that it is largely preventable.

The magnitude: neuroscientist Dr. Zachary Knight, on Huberman's podcast, puts it plainly — roughly 25% to 33% of the weight lost on a GLP-1 agonist is muscle mass. Attia calls that rate "alarming" and warns it can leave you with worse body composition despite a lower number on the scale. A key nuance several experts raise: a lot of this is a consequence of rapid weight loss in general (any aggressive calorie deficit does it), not a unique toxic effect of the drug — which is exactly why the fix is the same as for any rapid weight loss.

The fix is two levers, and the experts converge on both. First, protein: Dr. Abby Smith-Ryan (via Attia) targets 130-150g daily; Rhonda Patrick, citing Dr. Stu Phillips' meta-analysis, recommends about 1.6 g/kg (which beats 1.2 g/kg) and notes appetite suppression makes easily-digested protein important. Attia frames it as roughly 1g per pound of lean body mass. Second, resistance training 2-4x/week to give the body a reason to keep the muscle. Attia adds a measurement layer: track body composition with a DEXA scan, not just bodyweight, so you can confirm the weight you are losing is fat.

One honest counterpoint: Dr. Ralph DeFronzo (via Attia) notes that even when absolute strength dips slightly, functional measures — walking distance, getting out of a chair, even VO2 max — can still improve as people lose excess weight. The muscle concern is real and worth defending against, but it does not by itself make the drugs a bad trade for someone with significant weight to lose. It is most concerning for people without much fat to lose.