The claim: NMN supplements slow ageing
NMN.
A 2023 review of 10 small human trials of 8 to 48 people, lasting 14 days to 12 weeks.
Evidence level 4 of 5: small or short human trials. What this means
Popular in longevity circles, safe in short trials, but there is no evidence yet that it slows ageing in people.
- Evidence
- Weak: about 10 small human trials of 14 days to 12 weeks
- Cost
- An ongoing monthly cost for a benefit not yet shown in people
- Watch for
- Little long-term safety data in people; some animal studies raise questions
What it is
Nicotinamide mononucleotide (NMN) is a molecule the body uses to make NAD+, which declines with age. Supplements are sold on the idea that topping it up slows ageing.
What the research found
- A 2023 review in Advances in Nutrition covered 10 published human trials, with groups as small as 8 people and as large as 48.
- Trials lasted between 14 days and 12 weeks. None measured lifespan or long-term health in people.
- NMN was well tolerated in these trials, but the reviewers noted limited information on its full toxicology.
- Results were mixed: one trial in 25 women with prediabetes found better muscle insulin sensitivity, and some trials in older adults saw small gains on a strength or walking test. Sleep and fatigue showed no clear change.
- Most of the anti-ageing evidence for NMN still comes from cell and animal studies.
Where this evidence sits
- 1Guidelines and expert position statements
- 2Reviews of randomised trials
- 3Large long-term studies of people
- 4Small or short human trialsThis check
- 5Animal and lab studies
The bottom line
NMN may turn out to matter, and larger trials are under way. Today, the human evidence is too small and too short to justify the cost. Spend the money on the things rated Works.
Sources
- The Safety and Antiaging Effects of Nicotinamide Mononucleotide in Human Clinical Trials: an Update — Song et al., Advances in Nutrition, 2023
- Human Clinical Trials of NMN for Safety and Effectiveness — Lifespan.io, 2023 (summary of the review above)
Last reviewed 10 October 2026. Ratings change when the evidence does. This is general information, not medical advice: talk to your doctor before changing medication or treatment.