Peptides Clarified

Metformin vs. Rapamycin for longevity interest

Summary

Both are FDA-approved for other uses and attract off-label longevity interest. Neither is FDA-approved for aging. Metformin has a large trial (TAME) designed to test aging-related outcomes; rapamycin's longevity evidence is largely from animals.

At a glance

Metformin

FDA-approved for
Type 2 diabetes
Longevity evidence in humans
Limited (observational; TAME trial designed)
Key risk
Rare lactic acidosis; B12 lowering

Rapamycin (Sirolimus)

FDA-approved for
Transplant rejection; LAM
Longevity evidence in humans
Preclinical (mostly animal data)
Key risk
Immunosuppression; infection risk

What they have in common

  • Both are used off-label by people interested in healthy aging.
  • Neither has proven anti-aging benefit in healthy humans.
  • Both require clinician oversight and monitoring.

Material differences

  • Metformin has a long diabetes safety record; rapamycin is an immunosuppressant with more monitoring needs.
  • Metformin's aging hypothesis is being tested prospectively (TAME); rapamycin's is not at that scale in humans.

Decision considerations

  • That neither is FDA-approved for longevity.
  • Your kidney function (metformin) or infection risk (rapamycin).
  • The strength and limits of the current evidence.
  • Monitoring that would be required.

Sources

  1. 1.TAME — Targeting Aging with Metformin American Federation for Aging Research (AFAR). Professional organizationAccessed July 24, 2026.
  2. 2.A Critical Review of the Evidence That Metformin Is a Putative Anti-Aging Drug PMC / NCBI (peer-reviewed review). Systematic reviewAccessed July 24, 2026.
  3. 3.RAPAMUNE (sirolimus) — Prescribing Information U.S. Food and Drug Administration. Government agencyAccessed July 24, 2026.
  4. 4.Rapamycin for longevity: the pros, the cons, and future perspectives PMC / NCBI (peer-reviewed review). Systematic reviewAccessed July 24, 2026.
Last reviewed (yesterday)