Is rapamycin safe for anti-aging and longevity?

Short Answer: Low-dose, intermittent rapamycin (e.g., 5mg weekly) appears well-tolerated in healthy adults based on early clinical trials, with mouth sores being the most common side effect. Long-term safety data is still being collected.

Evidence Level: moderate

Detailed Answer

Rapamycin (sirolimus) is the most robust pharmacological life-extension intervention in mammals, extending median lifespan 10-25% across multiple mouse studies (ITP program). The PEARL trial (NCT04488601) tests 5mg weekly rapamycin in healthy older adults. At this low intermittent dose, rapamycin primarily inhibits mTORC1 while sparing mTORC2, avoiding the immunosuppression and metabolic side effects seen at higher transplant doses. The most common side effect is aphthous stomatitis (mouth sores, ~25%), usually self-limiting. Mannick et al. (2014, Sci Transl Med) showed low-dose mTOR inhibition actually enhanced immune function in elderly subjects. Lipid elevation is possible but typically mild. Rapamycin is a CYP3A4 substrate — grapefruit juice increases levels 3.5x. Medical supervision is essential.

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