Does rapamycin help people live longer in good health?
Rapamycin works in mice, but whether it also leads to a longer and healthier life in humans has not yet been demonstrated. Side effects are real, long-term data in healthy people are absent, and use outside a clinical context cannot currently be justified.
Rapamycin reliably extends the lifespan of mice, and was the first drug shown to do so in a mammal in both sexes. The same has been shown in yeast, worms and flies. Whether this effect in mice occurs because ageing as a whole is slowed down, or because cancer is suppressed (the leading cause of death in many mouse strains), has not yet been resolved. The evidence points most strongly to the second scenario, supplemented by modest effects on things such as cognitive decline.
In humans the data are more limited, but not absent. A systematic review of 19 clinical studies found indications that rapamycin and related compounds have beneficial effects on the immune system, the cardiovascular system and the skin. No significant effects were found on the nervous system, muscles or hormonal system.
Rapamycin is not a risk-free drug. More infections were observed in people with ageing-related conditions, and cholesterol and triglyceride levels rose. Some of these side effects appear to arise because rapamycin, with prolonged use, also inhibits a second protein complex inside the cell. Researchers are investigating whether intermittent dosing or more selective molecules can reduce this risk, but that remains at an experimental stage.
An observational study of 333 healthy adults using rapamycin off-label reported no serious side effects. That finding is neither reassuring nor a green light: the data are self-reported, there is no control group, and the researchers are affiliated with clinics that prescribe the drug themselves. Long-term data in healthy people are entirely absent.
Computer analysis identified a number of natural compounds, such as EGCG from green tea, that resemble rapamycin at the cellular level. Whether these also have any effect in humans has not been demonstrated. This is purely exploratory and provides no basis for recommendations.
This answer is based on a systematic review of 19 clinical studies in humans, three reviews on animal research and mechanisms, and an observational study in 333 healthy adults. The evidence in mice is strong and causal; the evidence in humans is moderate and has not yet been tested against hard endpoints such as lifespan. The systematic review in humans examined ageing-related biomarkers, not disease or mortality as outcomes. The observational safety study carries an elevated risk of bias due to the authors' involvement with commercial providers of rapamycin.
What do we know about rapamycin as an anti-ageing agent in humans?
Rapamycin shows measurable improvements in immune function and cellular ageing markers in people. Whether it also extends lifespan or genuinely slows ageing has not yet been demonstrated.
Will a doctor prescribe rapamycin?
Most doctors will not prescribe rapamycin to healthy people to slow ageing, simply because the evidence for doing so is still lacking. For certain rare conditions a specialist may consider it off-label, but always with a careful weighing of the risks.
Does metformin help you live longer in good health?
For people with diabetes, metformin has a reasonably well-supported health benefit, but as an anti-ageing agent for healthy people it remains unproven. Wait for the results of that large ongoing study before drawing conclusions.
Is rapamycin hard on the liver?
Rapamycin itself shows no measurably greater direct liver damage than alternative treatments in studies. The related drug everolimus measurably increases the chance of abnormal liver enzymes and raised blood fats.
Does rapamycin improve skin aging?
Topical rapamycin showed promising signs for skin ageing in a small study, but the evidence is still too thin to justify self-application.
Can rapamycin reverse or prevent grey hair?
Rapamycin shows promising effects on grey hair in cell and animal studies, but it has not been tested in people. It is too early to use it for this purpose.