Does rapamycin help people live longer in good health?

Rapamycin works impressively well in mice: it clearly extends their lifespan. But what works in mice does not always translate the same way in humans, and that is precisely the problem here. The human studies that exist are small and short, and they measure things like immune response or vaccine effectiveness rather than actual lifespan or long-term health. The most promising signal, a better immune response in older adults, did not hold up when it was tested in a larger, carefully designed study. That is not a trivial finding.

The 48-week PEARL study in healthy older adults did show some hints of certain effects, but the primary outcome measure was not met, and the results differed between men and women. In short: there is currently no demonstrated benefit for health or lifespan in humans.

On top of that, rapamycin is a real drug with real risks: it suppresses the immune system, which increases the risk of infections, and it can raise blood lipids and blood sugar. Long-term use in healthy people, outside the approved indications such as transplantation, has simply not been studied from a safety perspective. It is not known what years of use will do. In the Netherlands it is available by prescription only and is not approved for lifespan extension.

If you are considering it: right now the unknown risks outweigh the absence of proven benefit. It is a compound worth watching because research is ongoing, but the current state of evidence does not justify use outside a clinical trial.