A mouse study suggests a hidden culprit behind muscle loss on weight-loss drugs — and blocking it might help keep muscles strong.

Other research shows that when mice on semaglutide had 15-PGDH blocked, they kept about 30% more muscle mass and regained strength faster after injury — without losing the fat-burning effect. That’s a compelling clue, but the original study linked in the post didn’t actually measure whether semaglutide raises this enzyme at all. It only showed that blocking it reversed muscle loss, which implies a connection but doesn’t prove how it starts. And while the results in mice are striking, no human trials have tested this yet. So we’re seeing a promising puzzle piece, not a finished picture.

If you're on a GLP-1 drug and worried about muscle loss, lifting weights and eating enough protein are still your best bets — but this mouse research might point to a future way to protect muscle without giving up the weight loss.