NMN and healthy ageing: what does the evidence show?

What are NMN and NAD?

NMN stands for nicotinamide mononucleotide. It is a precursor: a substance the body can use to make nicotinamide adenine dinucleotide, known as NAD. NAD helps cells carry out many reactions, including ones involved in energy metabolism. It is related to the biology of vitamin B3, but NMN, NAD and the different forms of niacin are not interchangeable products. Knowing that a molecule has an important role does not establish that taking more of a precursor improves health. For a different compound marketed for cellular health, see urolithin A and muscle evidence.32

What did a human trial find?

In a double-blind, randomised trial, 25 postmenopausal women with prediabetes and overweight or obesity received NMN or a placebo for 10 weeks; the insulin-response comparison included 13 participants in the NMN group and 12 in the placebo group. Researchers found improved insulin sensitivity in skeletal muscle in the NMN group: muscle responded better to insulin during a measurement. Blood-cell NAD also increased. Other measures of metabolic health did not show corresponding improvements. The study was small, short and limited to a particular group; it did not test whether NMN prevents diabetes, extends life or improves outcomes in other populations.

The researchers measured NAD in two different places: the increase was in a type of blood cell, while measured NAD in sampled muscle tissue did not change over the study. That does not rule out changes in how muscle uses NAD; the authors proposed a possible increase in turnover, which remains an interpretation rather than a directly established explanation. The study also found no clear difference in fasting blood glucose or liver insulin response between groups. One author disclosed receiving patent-licensing fees from two companies through their university and another disclosed an NMN-related patent application.12

What about walking and sleep?

A 2024 randomised trial assigned 60 older adults to NMN or placebo for 12 weeks. Its main measure, a stepping test, did not differ significantly between groups. Some secondary measures, including a short walking test and sleep scores, favoured NMN; those findings need confirmation in larger trials designed to test them. The study included authors employed by Meiji Holdings. Its selected participants and short duration limit what it can tell us about other people or lasting effects.5

Does a longer trial show a functional benefit?

In a 2026 double-blind trial, generally healthy Japanese adults aged 65 and older were assigned a particular NMN preparation or placebo for 24 weeks. The NMN group showed an increase in blood NAD and related compounds, but researchers did not find a statistically significant improvement in the main outcome, hearing, or in measured physical performance. Some other measurements appeared to change, but those findings did not remain statistically significant after adjustment for testing many outcomes and are exploratory.9

The study was funded by MIRAILAB BIOSCIENCE, which supplied the NMN; company employees were among the authors. The authors state that the company did not control the study design, analysis or publication decision. The trial was small and excluded many health conditions, so it cannot rule out all benefits or harms in other groups. Six months is longer than some NMN studies but cannot establish effects on lifespan or rare and delayed harms. The publisher describes the available report as an accepted article subject to further editing.9

Is NMN better than nicotinamide riboside?

NMN and nicotinamide riboside (NR) are different substances involved in pathways that can produce NAD. A 2026 study directly compared them with nicotinamide, another related substance, and placebo in healthy adults. Researchers randomly assigned 67 participants; 65 were included in the main analysis after two received the wrong product. After 14 days, NMN and NR produced similar increases in a blood NAD measurement; nicotinamide did not show the same sustained increase. Participants and researchers knew which product was assigned, and several authors worked for Nestlé Research or Nestlé Health Science.7

This small, short study measured blood chemistry, not lifespan, disease prevention, physical performance or long-term safety. Similar blood measurements do not establish that the products have equal effects throughout the body, and the trial does not show that either is better for healthy ageing. Laboratory work with stool samples suggested a possible role for gut microbes, but a proposed mechanism is not proof of a health benefit. For the wider nutrient context, see vitamin B3.7

Does more NAD mean less fatigue? In a separate trial, the report’s results say 61 adults with long COVID were randomised to NR or placebo and 58 completed baseline testing; its abstract describes 58 as randomised. The placebo group switched to NR after 10 weeks. Blood NAD rose with NR, but the comparison with placebo did not show a statistically significant improvement in fatigue, cognition, sleep or mood. Later exploratory analyses looked at changes while people took NR without the same between-group comparison; those findings cannot establish that NR caused an improvement. Of those who completed baseline testing, 12 of 37 assigned to NR and 3 of 21 assigned to placebo had left the study by week 10. Participants withdrew for several reasons; these counts do not establish that NR caused the difference. The small study received funding from several sources including NR maker Niagen Bioscience, and cannot rule out a benefit or harm in other groups. It studied NR, not NMN.8

Why a higher NAD measurement is not an anti-ageing result

A blood marker is a measurement, not a direct measure of how long or how well someone will live. Results in blood cells do not automatically describe every tissue, and results in animals do not establish the same benefit in people. Better evidence would include larger, longer independent trials measuring outcomes people can notice or that matter to health, alongside adverse effects. Learn more about reading a study result.21

Safety and product claims

A short trial cannot establish long-term safety, uncommon harms or interactions in people taking medicines. A product sold under the same ingredient name is not necessarily identical to the formulation tested. Check the complete product label, avoid treating testimonials as proof, and ask a pharmacist or clinician about individual circumstances and possible interactions. See how to read a supplement label and supplement–medicine interactions. A 2026 review pooled safety data from 10 trials involving 383 participants and found no clear increase in short-term adverse events; small, short studies cannot rule out rare or delayed harms.416