Healthy Ageing & Longevity - Longevity claims
Longevity supplements and pathway hype
Last updated 30 September 2026. How we write this .
No supplement has been shown to make people live longer. NMN, NR and resveratrol nudge molecules linked to ageing, but human trials so far are small, short and mostly find little effect on health.
Start here No supplement has been shown to make people live longer. NMN, NR and resveratrol nudge molecules linked to ageing, but human trials so far are small, short and mostly find little effect on health.
By the end, you will understand Why do these supplements sound so convincing? Do NMN and NR work in people? What happened with resveratrol? Key words used in this lesson Placebo An inactive comparison given so that the effect of expectation can be separated from the effect of the intervention itself. Without one, improvement over time cannot be attributed to the treatment. Full plain-English glossary
Where this information comes from Claim-cited evidence. Central research claims on this lesson are linked to specific studies or official guidance.
This lesson links the specific studies and guidance used for its central claims.
Nicotinamide mononucleotide increases muscle insulin sensitivity in prediabetic women - Science, 2021Effects of nicotinamide mononucleotide on glucose and lipid metabolism in adults: a systematic review and meta-analysis of randomised controlled trials - Current Diabetes Reports, 2024A randomized placebo-controlled clinical trial of nicotinamide riboside in obese men: safety, insulin-sensitivity, and lipid-mobilizing effects - American Journal of Clinical Nutrition, 2018High-dose resveratrol supplementation in obese men: an investigator-initiated, randomized, placebo-controlled clinical trial of substrate metabolism, insulin sensitivity, and body composition - Diabetes, 2013Our standard: expert or athlete opinion may illustrate a viewpoint, but it is never treated as proof. Read the editorial policy .
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No supplement has been shown to extend human life or delay the diseases of ageing. The popular candidates, including NMN, NR and resveratrol, act on chemical pathways that clearly matter in yeast, worms and mice. In people, the trials so far are small and short, they measure blood markers rather than illness or survival, and most have found little or nothing.
Why do these supplements sound so convincing?
The excitement starts in animals. Blocking a growth-signalling pathway called mTOR extends lifespan in yeast, worms and fruit flies. In rodents, obesity and ageing reduce the body's production of NAD+, a molecule cells need to turn food into energy, and that loss seems to feed into metabolic problems. Resveratrol, a plant compound, appeared in animal and lab studies to improve weight-related risk factors through enzymes called sirtuins.
The marketing step is to say that if a pathway matters, a product that touches it must help you. That skips the slow, expensive part: testing whether people who take it actually stay healthier for longer. A molecule can rise in your blood without any benefit following.
Do NMN and NR work in people?
NMN (nicotinamide mononucleotide) and NR (nicotinamide riboside) are both building blocks the body can turn into NAD+. The most cited NMN trial, published in Science in 2021 by a team at Washington University in St Louis, gave NMN or a placebo for 10 weeks to 25 postmenopausal women with prediabetes who were overweight or obese. In the NMN group, muscle insulin sensitivity, meaning how readily muscle takes up sugar in response to insulin, was about 25% higher after treatment than before. It did not change on placebo.
The rest of the results were quieter. NAD+ levels inside muscle did not change. Body fat, liver fat, blood pressure, blood sugar and blood fats stayed the same in both groups. Two of the researchers declared NMN-related patent interests, which the paper disclosed.
When more trials arrived, the picture did not improve. A 2024 review in Current Diabetes Reports pooled eight randomised trials of NMN, involving 342 middle-aged and older adults, mostly without diabetes. The trials ran from two to 12 weeks. Together they showed no significant benefit for fasting blood sugar, fasting insulin, HbA1c (a measure of average blood sugar over about three months), insulin resistance or blood fats.
NR has a similar record. In a Danish trial published in the American Journal of Clinical Nutrition in 2018, 40 sedentary men aged 40 to 70 with obesity took NR or a placebo for 12 weeks. NR did not improve insulin sensitivity, sugar handling, energy use, fat burning or body composition. It did appear safe over that period, with no serious side effects and normal safety blood tests. None of these trials measured how long people lived, and none was designed to.
What happened with resveratrol?
Resveratrol has done poorly in human testing. In a trial at Aarhus University Hospital in Denmark, published in Diabetes in 2013, 24 men with obesity but otherwise healthy took high-dose resveratrol or a placebo for four weeks. Insulin sensitivity, the main outcome, did not improve. Nor did blood pressure, energy use, fat stored in the liver and around the organs, or markers of inflammation. The authors noted that this clashed with persuasive results in rodents, and said it raised doubt about resveratrol as a supplement for metabolic problems.
It also failed the most rigorous mouse lifespan test available, described below.
What do the mouse lifespan studies really show?
The best mouse evidence comes from the National Institute on Aging's Interventions Testing Program (ITP) in the United States. It tests candidate drugs at three separate laboratories, using mice bred so that each one is genetically unique, which makes a result harder to explain away as a quirk of one strain or one lab.
In 2009 the ITP reported in Nature that rapamycin, a drug that blocks mTOR, extended lifespan in both sexes even when started at 600 days of age, which is late in a mouse's life. Measured by the age at which 90% of the mice had died, lifespan rose by 14% in females and 9% in males. A 2011 follow-up started rapamycin at 9 months of age and extended median survival by 10% in males and 18% in females. In the same study, resveratrol had no significant effect on survival in either sex.
These are mouse results, and they come with a caution. Rapamycin is a prescription drug, not a supplement, and no trial has shown it extends human life. A compound that works in the ITP has passed a strong first test, not the final one.
What about metformin and the TAME trial?
Metformin is a long-established diabetes medicine that has been promoted as an anti-ageing drug. One reason for caution comes from the MASTERS trial, published in Aging Cell in 2019. The researchers expected metformin, which dampens inflammation, to boost the muscle-building effect of exercise. They gave 94 healthy adults aged 65 and over either metformin (46 people) or a placebo (48 people) during 14 weeks of supervised strength training. The placebo group gained more lean body mass and more thigh muscle than the metformin group. The drug blunted one of the best-proven benefits of exercise in later life.
TAME, short for Targeting Aging with Metformin, was planned to settle whether metformin can delay heart disease, cancer and cognitive decline in healthy older adults. The aim is to enrol 3,000 people aged 65 to 79 for six years. In April 2024, NPR reported that the US National Institute on Aging had set aside about 5 million dollars, against an estimated cost of 45 to 70 million dollars, and that the trial would begin once the money came in. So the best-known trial designed to test a drug against ageing itself has not produced any results.
Where does that leave longevity supplements?
The honest position is uncertainty rather than disproof. NAD+ and mTOR remain serious areas of research, and longer human trials may yet find something. But a trial that could show a supplement keeps people healthier for longer would need thousands of people, years of follow-up and outcomes such as illness, frailty or death. For NMN, NR and resveratrol, those trials have not been done. What exists are short studies of blood markers, and they mostly show no effect.
Supplements are not free of risk either. Some can interact with prescription medicines, so if you take any, tell your GP or pharmacist.
This lesson is general education about longevity supplements, not medical advice. Talk to your GP or pharmacist before starting or stopping any supplement or medicine.
Related in this classroom Related in other classrooms The studies behind this page Nicotinamide mononucleotide increases muscle insulin sensitivity in prediabetic women - Science, 2021Effects of nicotinamide mononucleotide on glucose and lipid metabolism in adults: a systematic review and meta-analysis of randomised controlled trials - Current Diabetes Reports, 2024A randomized placebo-controlled clinical trial of nicotinamide riboside in obese men: safety, insulin-sensitivity, and lipid-mobilizing effects - American Journal of Clinical Nutrition, 2018High-dose resveratrol supplementation in obese men: an investigator-initiated, randomized, placebo-controlled clinical trial of substrate metabolism, insulin sensitivity, and body composition - Diabetes, 2013Rapamycin fed late in life extends lifespan in genetically heterogeneous mice - Nature, 2009Rapamycin, but not resveratrol or simvastatin, extends life span of genetically heterogeneous mice - Journals of Gerontology Series A, 2011Metformin blunts muscle hypertrophy in response to progressive resistance exercise training in older adults: the MASTERS trial - Aging Cell, 2019A cheap drug may slow down aging. A study will determine if it works - NPR, April 2024Further reading
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Educational content only. Not medical advice, diagnosis or treatment. Always consult a qualified healthcare professional before changing your health regimen.