The Longevity Supplement Audit: What Survives Human Trials

NAD precursors, resveratrol, metformin, rapamycin, taurine — graded on the strength of the human evidence rather than the mechanism story.

NAD+ precursors — nicotinamide riboside and NMN — reliably raise blood NAD+ levels in humans. That is the whole of the settled finding. Trials looking downstream at physical function, insulin sensitivity, or inflammation have been small and mostly null or marginal, and raising a metabolite is not the same as improving a system.

Resveratrol is the cautionary case. Enormous mechanistic literature, sirtuin activation headlines, poor oral bioavailability, and a consistent failure to reproduce meaningful clinical effects. Trans-resveratrol supplementation has the best-documented gap between attention and outcome in this field.

Metformin and rapamycin are the two genuinely interesting candidates, and neither is a supplement. Metformin's mortality signal comes from diabetic populations compared with other diabetes treatments, which is not the same question as effects in healthy adults; the TAME-style trials exist to answer that and have not. Rapamycin has the strongest animal lifespan data of anything known, and an immunosuppression and dosing profile that makes off-label use a decision for a physician, not a shopping cart.

Taurine's 2023 rodent results were striking and were widely reported as though they had been human results. Human observational associations exist; a dose-finding intervention trial does not yet.

What actually holds up at this level of evidence is unglamorous: creatine monohydrate for strength and lean mass, vitamin D where deficiency is documented, omega-3 for triglycerides, and protein intake sufficient to support training. If a budget line has to go somewhere, it belongs there before it goes to a proprietary blend.

Every entry on this list is a mechanism in search of an outcome. Some are worth taking anyway; none are proven to extend life.

Editorial note: this article summarises published research for general information. It is not medical advice. Discuss any intervention with a qualified clinician.