The Honest Picture

Nothing on this page has been proven to extend human lifespan. That sentence is missing from most longevity content, so it leads this one. What the field actually has is a hierarchy of evidence, and knowing which tier a claim sits on is most of the skill of reading it.

Tier one — proven for healthspan: regular exercise (especially strength training), adequate sleep, not smoking, maintaining muscle mass, and social connection. These have decades of consistent human data on both quality and length of life. They are also free, which is why nobody advertises them.

Tier two — strong human signals, incomplete proof: sauna (large Finnish cohorts), Mediterranean-style eating patterns, caloric moderation, and maintaining metabolic health. The associations are robust; the controlled long-term trials are, and will likely remain, impossible to run for lifespan itself.

Tier three — compelling biology, animal results, early human trials: rapamycin, senolytics, NAD restoration, spermidine, taurine, glycine. This is where the exciting science lives — and where a mouse result is routinely marketed as if it were a human one. The individual pages in the Molecules and Protocols sections tell you exactly which species the key studies were run in.

Tier four — mechanism only, or failed trials: resveratrol is the cautionary tale — a spectacular mechanism story that repeatedly failed to translate. Treat any compound sold on mechanism alone as a hypothesis, not a therapy.

A final honest note: rapamycin and metformin are prescription drugs with real side-effect profiles, and "longevity clinics" prescribing them off-label are running an experiment, not delivering a proven treatment. If you join that experiment, do it with a physician who monitors you, not a subscription website.

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