Rapamycin
Evidence CWhat the evidence actually shows
Rapamycin is the poster child of geroscience for a good reason: it is the most reproducibly life-extending drug in laboratory animals we have. The NIA Interventions Testing Program — a rigorous, multi-site, deliberately hard-to-fool mouse study designed specifically to kill off the field's endless false positives — found that rapamycin extended both median and maximal lifespan in genetically heterogeneous mice, even when started in late middle age. Mechanistically it inhibits mTOR, a nutrient-sensing pathway sitting near the centre of most serious theories of ageing.
That is a real result and it is why serious people take the molecule seriously. The ITP does not hand out positive results easily; most compounds it tests do nothing. So the mouse evidence is not hype, it is arguably the strongest single data point that ageing itself is pharmacologically tractable. The problem is the word "mouse."
How big the effect really is, in years — in humans
Zero known. Not "small," not "uncertain," but genuinely unmeasured. There is no human trial with a lifespan or all-cause mortality endpoint, there is no observational cohort of longevity-dosed rapamycin users old enough to have generated a mortality signal, and there is no biological law that guarantees a mouse result transfers to a primate that lives thirty times as long. The history of geroscience is a graveyard of interventions that added months to a mouse and nothing measurable to a human.
What human data exists is about safety and surrogate markers — immune response in the elderly, some small trials on intermediate endpoints — not about whether anyone lives longer. That is a completely different question, and the honest actuarial answer to "how many years does rapamycin add to a human life" is that the evidence does not permit a number. Anyone who gives you one is extrapolating from rodents and hoping you will not notice the species boundary.
The catch: it is a real drug with real trade-offs
Rapamycin is not a supplement. It is an approved immunosuppressant with a genuine side-effect profile — impaired wound healing, mouth ulcers, metabolic effects on glucose and lipids, and immune modulation whose long-term consequences at intermittent "longevity" dosing simply have not been characterised in healthy people over decades. The optimistic case rests on intermittent low dosing avoiding the worst of this, which is plausible and also, at present, largely unproven.
We are not telling you not to be interested. We are telling you that the risk-benefit ledger for a healthy person has real, quantified entries on the risk side and a blank where the human benefit should be. That asymmetry is the entire point of grade C. If you are considering it, this is emphatically a clinician conversation, and ideally a clinical-trial conversation.
Why it earns no year-effect in the calculator
This is where we plant a flag. Rapamycin gets exactly zero years in the actuarial model, and that restraint is the brand. This calculator prices life expectancy from human mortality data. A drug with no human life-expectancy evidence cannot be assigned a human life-expectancy effect without us simply inventing a number, and inventing numbers is the precise thing the rest of the longevity internet does that we refuse to do.
So rapamycin lives here as directory content: fascinating, honestly described, evidence-graded C, and deliberately excluded from any slider that moves your actuarial age. If the day comes that a properly powered human trial reports a mortality benefit, we will price it like anything else. Until then, the responsible figure is zero, and we would rather show you a confident zero backed by reasoning than a flattering guess backed by a mouse. The discipline of not counting what we cannot measure is the whole reason this site exists.
Sources
Reviewed 2026-07-06 by Dmytro Dubina, Actuary · MSc Probability & Statistics · 20+ years in insurance. Population statistics, not medical advice.