Molecule
Rapamycin
Rapamycin (sirolimus)
The only compound to consistently extend lifespan across every animal species where it has been tested. Not a supplement, a prescription immunosuppressant.
Summary Can rapamycin help people live longer? Show / hide ↓
Rapamycin is a prescription medicine, not a supplement, and it suppresses the immune system. In mice, it extended lifespan in both sexes across several doses, ages, and three independent laboratories. It works by blocking mTOR, a system that controls cell growth, which may allow more cellular maintenance and autophagy, the cell’s recycling process. Human evidence is limited: one small one-year trial found no clear improvement in physical function, and long-term results are still unknown. Longevity users often take 5 to 8 mg once a week, but this is off-label and has not been proven in healthy people; possible problems include mouth ulcers, changes in blood fats, glucose intolerance, and immune suppression.
What this means for you: Rapamycin is promising in mice but has not been shown to extend human lifespan. It is a prescription drug with real risks, so it is not enough evidence to use it for longevity.
early evidenceRapamycin is the strongest single piece of evidence in longevity biology. In the NIH Interventions Testing Program, which subjects candidate compounds to lifespan trials in genetically diverse mice across three independent laboratories, rapamycin extended median lifespan in male and female mice, at multiple doses, initiated at multiple ages. Almost nothing else has passed that filter.
The mechanism is mTOR inhibition. mTOR is a cellular growth sensor. When it is chronically activated, cells prioritize growth over maintenance, including autophagy, which is the cell's own recycling process. Blocking mTOR shifts cells back toward maintenance.
Rapamycin is FDA-approved for organ transplant rejection and certain rare cancers, in daily doses of 2-5 mg. The longevity community uses far lower, intermittent doses, typically 5-8 mg once per week, to hit mTORC1 (implicated in aging) while avoiding mTORC2 inhibition (implicated in metabolic side effects). This dosing schedule is off-label and not supported by RCT evidence in healthy humans.
Side effects at intermittent dosing include mouth ulcers, mild lipid changes, and occasional glucose intolerance. Immune suppression is the top concern, though at longevity doses it appears modest. The PEARL trial in humans found no clear benefit on functional outcomes at 1 year, though the trial was small.
Rapamycin is not sold as a supplement anywhere. It requires a prescription. Clinicians who prescribe it off-label for longevity include Peter Attia and others in the anti-aging clinical community. It is not something to acquire from grey-market sources.
Further reading
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