Longevity Supplements and Drugs, Rated

NAD boosters, taurine, resveratrol, metformin and rapamycin — sorted by whether the evidence is human.

What this is

The longevity compound market runs on a specific pattern: a striking result in worms, mice or monkeys, followed by a supplement launch, followed — sometimes years later — by human trials showing the biochemical change happens and the functional benefit doesn't. Reading the tier and the basis on each row below is the whole skill.

The taurine story is the clearest recent example. A 2023 Science paper reported that taurine declines with age and that supplementation extended healthspan in mice and improved measures in monkeys — a genuinely interesting finding, immediately marketed as a human longevity intervention. In 2025, experimental work in humans published in Aging Cell argued against taurine deficiency being a driver of human ageing. Both papers are real science; only one of them was on the label.

What the evidence says

  • NAD precursors (NR, NMN) raise blood NAD levels in humans

    Gold· human data

    Reliably demonstrated across trials. This is the part the marketing is right about, and it's a biochemical outcome, not a health one.

  • NAD precursors improve function, cognition or muscle in humans

    Unproven

    Systematic reviews of NMN and NR find no significant benefit on glucose, insulin, HbA1c, lipids or muscle outcomes in mostly short trials. The NAD number moves; the person doesn't.

  • Taurine extends healthspan — in animals

    Bronze· animal data only

    Strong effects in mice and worms, healthspan effects in monkeys, and human data limited to correlations. Subsequent human experimental work has challenged the deficiency-drives-ageing premise.

  • Rapamycin extends lifespan in mice

    Gold· animal data only

    One of the most reproducible findings in ageing biology. It is also an immunosuppressant with meaningful side-effects, and there is no lifespan or healthspan trial in healthy humans.

  • Metformin slows ageing in healthy people

    Unproven

    The evidence is preclinical plus disputed observational data in people with diabetes. The TAME trial designed to test it has not reported efficacy results, and any claim that it has is wrong.

  • Resveratrol as an anti-ageing intervention

    Not supported

    The original sirtuin-activation story didn't survive replication, and human trials have not delivered. It remains widely sold.

What this means in practice

  • Sort every longevity claim by basis first: human, animal or in-vitro. Most of the market is animal.
  • Ask what outcome moved. "Raises NAD" is a mechanism; "walks further, lives longer, thinks more clearly" is a result.
  • Spend the budget where the human data are: training, sleep, blood pressure, not smoking, protein intake.
  • If you're considering an off-label prescription drug for ageing, that conversation belongs with a doctor who will monitor you.
  • Our supplement database grades individual compounds; use it before buying anything in this category.

When to see a doctor

  • Any product claiming to reverse ageing, with before-and-after biological age scores as evidence.
  • Sellers who also sell you the test that proves their product worked.
  • Prescription medicines offered without examination or monitoring.

The honest summary

The longevity aisle sells mechanisms and mouse data at human prices. NAD precursors do exactly what they say biochemically and nothing yet functionally; rapamycin has the best animal evidence and real risks; metformin's headline trial hasn't reported. The interventions with human outcome data remain unglamorous and largely free.

Work it out

See also

Frequently asked questions

Do NMN or NR supplements work?
They reliably raise blood NAD levels. Systematic reviews of clinically relevant outcomes — glucose, lipids, muscle function, cognition — find no significant benefit in the trials done so far, which are mostly short and small.
Should I take taurine for longevity?
The 2023 mouse and monkey data were genuinely interesting; human experimental work published since has argued against the underlying premise. It's cheap and appears safe, but this is an animal-data story at present.
Is metformin proven to slow ageing?
No. The TAME trial designed to test this hasn't published efficacy results, and human evidence outside diabetes is observational and disputed. Any article claiming it's proven is inaccurate.
What about rapamycin?
It has the strongest animal lifespan evidence in the field and no human lifespan or healthspan trials, plus immunosuppressive effects and real side-effects. That combination is why serious researchers describe it as promising and unproven.

Sources

Written and reviewed by Mathew Beale, MSc Biotechnology, University of Reading.

Last reviewed: