How is rapamycin dosed in the longevity studies?

The mouse lifespan data behind rapamycin's reputation as a longevity drug didn't use one fixed protocol. Two separate findings matter: rapamycin still works when started late in life (not just from birth), and it still works when given only briefly rather than continuously. Neither finding has been replicated with a matched dosing protocol in a human lifespan trial – that trial doesn't exist and may never be practical to run. Using rapamycin for longevity is off-label, and no dose or schedule has been established for people.

Late-onset, continuous dosing

• HAR2009 A – rapamycin fed starting at 600 days of age – late-middle-age for a mouse – extended both median and maximal lifespan in both sexes (age at 90% mortality rose 14% in females and 9% in males). This was the finding that established rapamycin doesn't need to start early to work.

Brief, late-life dosing

• BIT2016 A – just 3 months of rapamycin, given late in life, increased subsequent life expectancy by up to 60% – the lifespan benefit doesn't require lifelong daily dosing, at least in mice. The 60% figure comes from males on the high injected dose. At that dose females gained no survival benefit and developed more aggressive blood cancers; the lower dietary dose raised survival in both sexes, so dose and route matter as much as the pulse.

Why intermittent/pulsed dosing is a live research question, not settled practice

If a few months of treatment can extend lifespan as much as continuous dosing in mice, the practical implication for humans is large: intermittent dosing could in principle deliver most of the benefit while limiting cumulative exposure to side effects like the mTORC2-linked insulin resistance discussed in the Atlas's side-effects answer page. But the specific schedule – how often, how much, for how long – hasn't been established in humans at longevity-relevant doses. This is tracked directly by two of the Atlas's open questions: muscle-sparing pulsed mTORC1 inhibition and mTORC1-selective, mTORC2-sparing dosing.

What human trials have actually tested

• KRA2018 H – a safety-first pilot RCT in older adults (n=25, ages 70–95) testing daily low-dose rapamycin over 8+ weeks for basic tolerability – not a lifespan endpoint.
• MOE2025 H – the first completed long-term RCT of rapamycin for healthy human aging (48 weeks, n=114) – still not a lifespan endpoint, and its primary metabolic endpoint showed no significant change.

Related entities

Open in the Atlas explorer