Head to head
Rapamycin against Metformin
The two drugs longevity clinics prescribe most, with opposite evidence shapes. Rapamycin extends lifespan across animal models and has no human ageing outcome; metformin has enormous human safety data, a consistently null geroscience record, and blunts the muscle and fitness gains from training.
Column A
RapamycinRapamycin (Sirolimus, mTOR inhibitor)
An FDA-approved mTOR inhibitor that extends lifespan in animals and is widely studied off-label at low, intermittent doses for longevity.
Column B
MetforminMetformin hydrochloride (biguanide)
The most discussed drug in longevity, with enormous human safety data and a geroscience record that is consistently null. It also blunts the muscle and fitness gains from training.
Side by side, on the facts we can check
| Attribute | Rapamycin | Metformin |
|---|---|---|
| Category | Longevity | Longevity |
| FDA status | FDA-approved (Rapamune); longevity use is off-label and investigational | FDA approved for type 2 diabetes since 1994. Not approved for ageing or longevity. |
| Half-life | ~60 hours | 4 to 9 hours (plasma), longer in erythrocytes |
| Molecular weight | 914.2 Da | 129.2 Da (165.6 Da as hydrochloride) |
| Mechanism | Inhibits the mTOR pathway, mimicking aspects of caloric restriction and enhancing autophagy and cellular maintenance. | Inhibits mitochondrial complex I and activates AMPK, reducing hepatic glucose output and improving insulin sensitivity. The AMPK account is incomplete and the relative contribution of complex I inhibition, mitochondrial glycerophosphate dehydrogenase and gut-mediated effects is actively disputed between research groups. |
| Human studies cited | 2 | 3 |
| Legal status, US | FDA-approved (for its labeled use), prescription only | Prescription only; approved for type 2 diabetes |
Frequently asked questions
What is the difference between Rapamycin and Metformin?
Rapamycin: An FDA-approved mTOR inhibitor that extends lifespan in animals and is widely studied off-label at low, intermittent doses for longevity. Metformin: The most discussed drug in longevity, with enormous human safety data and a geroscience record that is consistently null. It also blunts the muscle and fitness gains from training.
Which has stronger research evidence, Rapamycin or Metformin?
This database does not grade compounds. It counts what was run in people: 2 of the 3 studies cited on the Rapamycin profile were human work, against 3 of 4 for Metformin. Those counts are of our own citation lists and understate any larger literature, and neither is a recommendation.
Are Rapamycin and Metformin FDA-approved?
Rapamycin: FDA-approved (Rapamune); longevity use is off-label and investigational. Metformin: FDA approved for type 2 diabetes since 1994. Not approved for ageing or longevity..
Related posts
Blog articles that cover Rapamycin or Metformin, newest first.
- Dispatch / Sep 12, 2026 / 8 minDispatch 001: Five Retatrutide Phase 3 Trials Have Finished And None Has Posted Results
- Longevity / Sep 8, 2026 / 12 minPeptides for Longevity: What the Evidence Actually Shows in 2026
- Longevity / Sep 8, 2026 / 9 minSenolytics in 2026: Dasatinib plus Quercetin, Fisetin, and What Human Trials Have Shown
- Longevity / Sep 8, 2026 / 9 minThe Rapamycin Dosing Debate: What PEARL Tested, the Bioavailability Problem, and What Is Unproven
Reviewed Sep 2026. This page sets two published records side by side. It is educational, it is not medical advice, and it contains no dosing protocols or recommendations for personal use.