Head to head
Rapamycin against Spermidine
Two ways to reach autophagy, a prescription immunosuppressant and a polyamine found in food. Spermidine's human case is population association with lower mortality; rapamycin's is animal lifespan data, and neither has a randomised ageing outcome in people.
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
SpermidineSpermidine
A natural polyamine that induces autophagy, linked in population studies to lower mortality and studied for cardiovascular and cognitive aging.
Side by side, on the facts we can check
| Attribute | Rapamycin | Spermidine |
|---|---|---|
| Category | Longevity | Longevity |
| FDA status | FDA-approved (Rapamune); longevity use is off-label and investigational | Sold as a supplement / food component; not an approved drug |
| Half-life | ~60 hours | Short |
| Molecular weight | 914.2 Da | 145.2 Da |
| Mechanism | Inhibits the mTOR pathway, mimicking aspects of caloric restriction and enhancing autophagy and cellular maintenance. | Induces autophagy by inhibiting acetyltransferase activity, helping cells clear damaged components associated with aging. |
| Human studies cited | 2 | 1 |
| Legal status, US | FDA-approved (for its labeled use), prescription only | Sold as a dietary supplement |
Frequently asked questions
What is the difference between Rapamycin and Spermidine?
Rapamycin: An FDA-approved mTOR inhibitor that extends lifespan in animals and is widely studied off-label at low, intermittent doses for longevity. Spermidine: A natural polyamine that induces autophagy, linked in population studies to lower mortality and studied for cardiovascular and cognitive aging.
Which has stronger research evidence, Rapamycin or Spermidine?
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 1 of 3 for Spermidine. Those counts are of our own citation lists and understate any larger literature, and neither is a recommendation.
Are Rapamycin and Spermidine FDA-approved?
Rapamycin: FDA-approved (Rapamune); longevity use is off-label and investigational. Spermidine: Sold as a supplement / food component; not an approved drug.
Related posts
Blog articles that cover Rapamycin or Spermidine, newest first.
- 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.