Prescription medicine
Rapamycin
Rapamycin is the most credible pharmaceutical longevity candidate from animal research: it reliably extends lifespan in mice, which almost nothing else does. It is also a prescription immunosuppressant with real side effects. Human evidence is at the stage of small trials of low-dose regimens measuring safety and immune function — not lifespan.
Quick verdict
The animal case is unusually strong; the human case is unusually early. Small trials of low-dose mTOR inhibition have produced mixed results on immune function, a recent one-year safety trial reported low-dose rapamycin as generally well tolerated, and nothing in humans has measured lifespan.
The assessment
Claim by claim
Each claim is graded on its own evidence. A grade for one claim says nothing about the others.
| Claim | What was measured | Evidence |
|---|---|---|
| Is tolerable at low doses in healthy adults over a year | Safety | Early |
| Improves immune function in older adults at low doses | Surrogate biomarker | Mixed |
| Extends human lifespan | Lifespan | Insufficient |
Is tolerable at low doses in healthy adults over a year
Early human evidenceOutcome measured: Safety — Adverse events, tolerability or harm were measured.
The PEARL trial followed healthy adults on intermittent low-dose rapamycin for a year, reporting on safety and healthspan-related measures.
Why this grade — the appraisal in full
One or a small number of small, short or preliminary human studies. Directionally interesting, not yet dependable.
- Strongest study design. Randomised controlled trial.
- Human research volume. 1 human study, 0 participants in total.
- What was measured. 1 human study measured a clinical or functional outcome rather than a laboratory marker alone.
- Replication. The supporting result has not been independently replicated in humans.
- Study duration. Longest human study ran 48 weeks.
Limitations. A single, relatively small trial; one year cannot establish long-term safety of chronic use, and some outcome measures showed effects only in subgroups.
| Study | Design | Population | Finding |
|---|---|---|---|
| [1]Influence of rapamycin on safety and healthspan metrics after one year: PEARL tr…Aging · 2025 · PMID 40188830 | Randomised controlled trialHuman | Size not recordedHealthy participants | Supports the claimPEARL: one-year randomised trial of intermittent low-dose rapamycin; safety and healthspan metrics. |
Improves immune function in older adults at low doses
Mixed evidenceOutcome measured: Surrogate biomarker — A laboratory marker measured as a stand-in for health. A change here does not by itself demonstrate a health benefit.
A 2014 trial found low-dose mTOR inhibition improved influenza vaccine response in older adults, and a 2018 follow-up reported fewer infections. But the subsequent phase 3 programme failed to confirm clinical benefit, and development was halted.
Why this grade — the appraisal in full
Human studies disagree, with credible trials on both sides, or results reverse under better methodology.
- Strongest study design. Randomised controlled trial with 218 participants.
- Human research volume. 3 human studies, 218 participants in total.
- What was measured. 2 human studies measured a clinical or functional outcome rather than a laboratory marker alone.
- Replication. Findings point the same way in 2 independent human studies.
- Study duration. Longest human study ran 6 weeks — too short to show durable effects.
- Funding and conflicts. 3 of 3 human studies were funded by, or authored by, a party with a commercial interest in the result.
Limitations. The positive trials used everolimus or related compounds rather than rapamycin itself, measured largely surrogate outcomes, and the confirmatory phase 3 failed — a textbook example of early promise not surviving rigorous testing.
| Study | Design | Population | Finding |
|---|---|---|---|
| [2]mTOR inhibition improves immune function in the elderlyScience translational medicine · 2014 · PMID 25540326 | Randomised controlled trialHuman | 218 participantsHealthy participants | Supports the claimEverolimus improved influenza vaccine response in older adults. |
| [3]TORC1 inhibition enhances immune function and reduces infections in the elderlyScience translational medicine · 2018 · PMID 29997249 | Randomised controlled trialHuman | Size not recordedHealthy participants | Supports the claimTORC1 inhibition reduced reported infections in the elderly. |
| [4]Targeting the biology of ageing with mTOR inhibitors to improve immune function …The lancet. Healthy longevity · 2021 · PMID 33977284 | Randomised controlled trialHuman | Size not recordedHealthy participants | Found no effectPhase 2b/3 programme: the phase 3 did not confirm clinical benefit; development discontinued. |
Extends human lifespan
Insufficient evidenceOutcome measured: Lifespan — Death from any cause was measured.
No human study has measured whether rapamycin extends lifespan. The claim rests on consistent mouse data — the strongest animal evidence of any candidate, and still animal evidence.
Why this grade — the appraisal in full
Too little credible research exists to judge the claim either way.
- Available research. No usable studies are linked to this claim.
Limitations. Mouse lifespan results, however replicated, do not establish human benefit; dosing, duration and risk trade-offs in humans are unresolved.
Human evidence
4 studies in people.
- [1]Randomised controlled trial
- [2]Randomised controlled trial · 218 participants
- [3]Randomised controlled trial
- [4]Randomised controlled trial
Animal and laboratory evidence
Shown separately, and never used to support a human claim.
No preclinical study is currently linked on this page.
Before anything else
Safety and interactions
A prescription immunosuppressant. At transplant doses: infection risk, metabolic effects, impaired wound healing. Low intermittent dosing appears better tolerated in short trials, but long-term safety in healthy people is unknown. Not something to self-prescribe.
Regulatory and availability. Licensed for transplant medicine and certain rare conditions; any longevity use is off-label and should involve a doctor.
The ledger
Grade history
No grade on this page has changed since tracking began. When one moves — a new trial, a retraction, a corrected appraisal — the change is detected automatically and recorded on the public ledger.
Falsifiability
What would change our view
Adequately powered randomised trials in healthy older adults with clinical endpoints — infection rates, physical function, disease incidence — over years rather than weeks. Consistent replication of immune benefits would also matter.
Check everything
Sources
Every citation links to its PubMed record. Bibliographic details are retrieved from PubMed, not written by us.
- [1]Influence of rapamycin on safety and healthspan metrics after one year: PEARL trial results Moel M et al.. Aging. 2025. PMID 40188830 · doi:10.18632/aging.206235
- [2]mTOR inhibition improves immune function in the elderly Mannick JB et al.. Science translational medicine. 2014. PMID 25540326 · doi:10.1126/scitranslmed.3009892
- [3]TORC1 inhibition enhances immune function and reduces infections in the elderly Mannick JB et al.. Science translational medicine. 2018. PMID 29997249 · doi:10.1126/scitranslmed.aaq1564
- [4]Targeting the biology of ageing with mTOR inhibitors to improve immune function in older adults: phase 2b and phase 3 randomised trials Mannick JB et al.. The lancet. Healthy longevity. 2021. PMID 33977284 · doi:10.1016/S2666-7568(21)00062-3