"The researchers fed young adult male mice."

"That is very different from what happens in real‑world older people taking GLP‑1 drugs like semaglutide. In younger adults, muscle can often be built back after illness or after stopping these drugs. But once people are over about 55 or 60, the picture is much more worrying.

Current evidence suggests that a large chunk of the weight lost on these drugs in older adults is actually muscle, not just fat. Even with good habits – high‑protein diets and regular resistance exercise – we do not yet have solid human trials showing that older people can fully regain that lost muscle. On top of that, when someone stops the drug, the weight that comes back seems to be mostly fat rather than muscle, which may drive more inflammation and weakness.

So claims that a new add‑on (like blocking 15‑PGDH) will ‘protect muscle’ in older people are based on experiments in young male mice, not on real trials in older human beings. What we really need are proper studies in people over 60, with careful measurements of muscle and strength, before we reassure seniors that their muscles are safe on these medications."

"GLP‑1 drugs are powerful tools, but in people over 60 we urgently need proper human trials that prove we can protect muscle, not just mouse studies that sound reassuring."