01NMN
GRADE BPromisingA direct precursor to NAD+, a coenzyme central to cellular energy and repair whose levels fall with age.
Studied dose 250–2,000 mg/day
Best longevity supplements, ranked by evidence
Compounds sold over the counter — NMN, NAD+ precursors, spermidine, taurine — ranked by human-trial evidence, not marketing. Where the evidence is thin, the page says so instead of filling the gap with mouse studies.
Ranked by: strength of human evidence — grade A first, D last. Never by commission.
02Spermidine
GRADE BPromisingA naturally occurring polyamine found in wheat germ, aged cheese, mushrooms and soy, studied as an oral supplement for its role in autophagy — the cell's internal recycling process, which declines with age.
Studied dose 1.2 mg/day
03NAD+ (injectable)
GRADE BPromisingThe intact coenzyme itself, delivered by IV infusion or injection rather than taken as an oral precursor — sold both as a 'research use only' vial and, more visibly, as an IV drip at wellness clinics marketed for energy, anti-aging, hangovers and addiction recovery, with a much thinner direct-administration evidence base than the marketing implies.
Studied dose 10 mg/day IV for 7 days (heart failure trial)
04Taurine
GRADE CEarlyA sulphur-containing amino acid the body makes and also obtains from food, present in high concentrations in muscle, heart and retina.
Studied dose 1–6 g/day
Guides
In-depth comparisons and rankings
The best longevity supplements, ranked by human evidence
Most longevity supplements are graded on mouse data. Here is the same shelf ranked only on human clinical trials — and what almost nothing on it has proven.
Read the guide →Best longevity supplements for cellular health and repair
Only creatine, omega-3, NAD⁺ precursors, urolithin A, CoQ10 and glycine-plus-NAC show a measured repair effect in human trials; the rest is animal data.
Read the guide →What are the best science-backed longevity supplements?
'Science-backed' is the most abused phrase in supplements. Here is the five-question test and the short list that actually passes on human trials.
Read the guide →Best sleep aids, ranked by evidence.
Melatonin has modest evidence for insomnia and strong evidence for jet lag; magnesium, glycine, weighted blankets, valerian and CBD ranked on what each shows.
Read the guide →What are the best clinically proven longevity supplements?
Proven for what, in whom, at what dose? Creatine, omega-3, vitamin D, CoQ10 and protein have the only randomised trials on a clinical endpoint.
Read the guide →Best longevity supplements stack for men over forty.
Creatine, omega-3 and vitamin D (if deficient) are the only supplements with trial evidence for men over forty — after a blood panel and resistance training.
Read the guide →Which science-backed supplements can safely extend life?
Correcting vitamin D deficiency ranks first among supplements safely backed by human evidence; NMN, resveratrol and most others lack human trials.
Read the guide →Best anti aging supplements to extend life naturally.
Correcting a real vitamin D or B12 deficiency ranks first, well studied and safe; omega-3, creatine and collagen follow, while NMN and resveratrol lack it.
Read the guide →Complete supplement stack designed to extend lifespan effectively.
Correcting deficiencies, omega-3 in specific groups, creatine, fibre and protein make up the only stack with genuine human evidence for extending lifespan.
Read the guide →Senolytic supplements and drugs: what actually has human data
Fisetin, quercetin, dasatinib: which senolytics have real human trial evidence, what those trials actually measured, and what's still just a mechanism story.
Read the guide →Taurine and longevity: what the human evidence actually shows
The study that made taurine famous extended lifespan in mice, not humans. What the actual human trials show, the dose studied, and who should be careful.
Read the guide →Creatine and aging: the best-documented compound in longevity
Creatine has more human trials than any other longevity supplement, at a fraction of the price. What's proven for aging, the dose, and who should be careful.
Read the guide →Urolithin A for muscle and mitochondria: what the trials actually show
A 2022 RCT found urolithin A improved muscle strength but missed its primary endpoint. Here's what every human trial actually shows, and what's still unproven.
Read the guide →PCC1 and the grape-seed longevity pill: what the study actually showed
PCC1 extended mouse lifespan by 9.4% — by injection, starting in old age. Here is the full study, the human data that exists, and what the capsules leave out.
Read the guide →NMN vs NR: which NAD⁺ precursor has the better evidence?
Both raise NAD+ in humans and no trial has compared them head-to-head. What separates them is trial outcomes, safety history and where each is legal to buy.
Read the guide →The Longevity Brief
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