Rapamycin: The Most Studied Longevity Drug
Rapamycin (sirolimus) is an mTOR inhibitor licensed as an immunosuppressant for organ transplant patients. It is also the only drug shown to consistently extend lifespan in every model organism tested — mice, yeast, worms, flies. The effect size in mice is dramatic: 10–15% extension even when treatment starts late in life.
How It Works
Rapamycin inhibits mTORC1, a key nutrient-sensing pathway. By reducing mTORC1 activity, it mimics caloric restriction at the cellular level — triggering autophagy (cellular cleanup), reducing cellular senescence, and lowering the rate of age-related inflammation. These mechanisms are well-conserved across species.
Is Anyone Actually Taking It?
Yes. A small but growing cohort of longevity-focused physicians (particularly in the US) prescribe low-dose intermittent rapamycin off-label — typically 3–6mg once weekly, which avoids the immunosuppressive effects of the higher continuous doses used in transplant medicine. UK prescribing is very limited; most interested patients access it via specialist longevity clinics abroad or with the support of private GPs willing to monitor biomarkers.
Risks and Unknowns
Potential concerns include impaired wound healing, increased infection susceptibility at higher doses, and metabolic effects (glucose and lipid changes). The intermittent dosing used for longevity appears to reduce these risks significantly, but long-term human data is lacking. This is not a supplement you take without medical supervision.
⚕️ Rapamycin requires a prescription in the UK. Do not attempt to self-medicate. Discuss with a private GP or specialist if you’re interested in monitored off-label use.