Comparison
Metformin vs. Rapamycin (Sirolimus)
Metformin or rapamycin – which longevity drug is further along?
The short answer
Both are approved drugs for something other than what they are taken for in the longevity scene. Metformin has the much larger data base from decades of diabetes treatment and, with TAME, a planned trial meant to test its benefit for aging – it has not started to this day. Rapamycin has the stronger mechanistic rationale: mTOR inhibition is the best-understood aging pathway of all, and in mice the substance reliably extends lifespan. In humans, endpoint proof is missing for both. The difference lies in the risk: rapamycin is an immunosuppressant.
The numbers side by side
| Axis | Metformin | Rapamycin (Sirolimus) | Difference |
|---|---|---|---|
| Human evidenceHow much data from humans there is, and how good it is | 8 | 5 | Metformin better studied |
| MechanismHow well the chain of action is understood | 8 | 9 | Rapamycin better studied |
| Safety dataHow well safety has been studied – not how safe it is | 9 | 5 | Metformin better studied |
| Hype gap10 means: the marketing stays in line with the data | 5 | 4 | Metformin closer to the data |
| Track record of useHow much documented use in humans there is – does not measure whether it works | 10 | 9 | Metformin in use for longer |
| Assessment | Well supported, heavily overhyped · Thin human evidence | ||
“Track record of use” measures how long and how widely something has been used in humans – not whether it works. The BK-Score is a subjective assessment by Biohacking Kompakt based on published scoring rules. It is not a scientific rating, not the consensus of a medical society and not a medical recommendation.
Why these numbers
Metformin
Approved for type 2 diabetes for decades, with endpoint data and extensive pharmacovigilance. The longevity claim is something else: the trial that would be decisive for it has not been completed, and there are indications that metformin dampens training adaptations.
Rapamycin (Sirolimus)
The mTOR pathway is one of the best understood in aging research and convincing in model organisms. In humans, there are approved uses in transplant medicine but no longevity endpoint data; off-label use runs ahead of the evidence.
Frequently asked questions
Does metformin extend life?
For people without diabetes, this has not been shown. The hypothesis comes from observational data according to which people with diabetes on metformin in some cases lived longer than comparison groups without diabetes. Such comparisons are prone to systematic bias. The TAME trial is meant to settle the question and has been funded for years, but has not started.
Can metformin harm training?
There are studies showing that metformin can blunt training adaptation – for example the gain in mitochondrial function. That is a serious objection, especially for the very group that takes it for optimization.
Why do longevity researchers take rapamycin anyway?
Because the animal data are more consistent than for any other substance and the mechanism is understood. That is a reasoned bet, not proof. Anyone who takes it is taking an immunosuppressant without endpoint data in healthy people.
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Information only, not medical advice and no usage or dosage recommendation. Prescription and unapproved drugs belong in the hands of a physician.