What Is NMN? A Beginner's Guide to the NAD+ Supplement

Quick answer

What is NMN? NMN (nicotinamide mononucleotide) is a popular “longevity” supplement, but the honest picture is that most of the exciting results come from mice, not people. Human trials so far are small and short, and they reliably show that NMN raises a blood marker called NAD, but they have not shown clear, lasting health benefits [3][4][5][6][11]. We rate the evidence D: early and mostly about lab markers. Short-term safety looks reasonable in the studies done so far, but long-term data are missing.

What is NMN?

Your cells use a molecule called NAD+ to turn food into energy and to help run many routine “housekeeping” jobs. Levels of NAD+ are thought to fall with age. NMN is a building block your body can use to make NAD+, and it is also found in tiny amounts in some foods. Supplements are made to raise NAD+ levels. Whether raising them improves health in people is still unproven.

What might it help with?

Lab marker (what NMN does to blood levels)

Possible benefit	Rating	In plain words
Raising blood NAD levels	Promising	Several small trials found NAD rose [4][5][6][8]. This is a lab marker, not a health result

Health outcomes (what people can feel or measure)

Possible benefit	Rating	In plain words
Walking speed and physical function	Early	Small trials show mixed, small effects [4][6][7]; one pooled analysis found a modest, uncertain gain [13]
Blood sugar and insulin	Mixed	A small trial found better muscle insulin response [3], but pooled trials found no clear benefit for glucose or blood fats [11]
Blood vessel stiffness	No clear benefit	Not significant in a 36-person trial [10]
Slowing aging or living longer	Early (animal or lab only)	Mouse studies are encouraging [1][2]. No human trial has tested this

Ratings describe how good the research is, not a promise that it will work for you.

What the research says

• Mice. In a 12-month study, mice given NMN during normal aging gained less weight and were more active than untreated mice, among other changes [1]. PubMed · DOI Earlier work showed improvements in glucose handling in mice fed a high-fat diet [2]. PubMed · DOI Mice are not people, and many animal findings don’t carry over.
• Women with prediabetes (25 people, 10 weeks). 250 mg a day improved how well muscle responded to insulin. The authors declared patent and industry links [3]. PubMed · DOI
• Older men (42 people). 250 mg a day raised NAD; walking speed and grip strength showed small changes that were only nominally significant, and body composition didn’t change. Some authors worked for a company with an interest [4]. PubMed · DOI
• Middle-aged adults (80 people, 60 days). 300, 600 or 900 mg a day raised blood NAD and increased 6-minute walking distance, but did not change an insulin-resistance measure; it was well tolerated [5]. PubMed · DOI
• Older adults (60 people, 12 weeks). The main test (a stepping test) showed no difference; some secondary measures such as walking time and sleep quality improved. Some authors worked for the sponsor [6]. PubMed · DOI
• Pooled results. A review of 8 trials (342 people) found no significant benefit for glucose or blood fats [11]. PubMed · DOI A 2026 review of 15 trials found no rise in side effects and no broad metabolic benefit [12]. PubMed · DOI Another found a modest, uncertain gain in walking speed [13]. PubMed · DOI

Amounts and how people take it

These are amounts used in studies, not recommendations.

• Most common trial dose: 250 mg a day, for 6 to 12 weeks [3][4][6][7][8].
• Range tested: 300 to 900 mg a day for 60 days in one trial [5], and 300 to 1,200 mg a day for 6 weeks in amateur runners [9]. In the 2026 EU safety opinion, 300 mg a day was assessed as safe for adults (not pregnant or breastfeeding) [14].
• Form and timing: we found no good evidence on the best form or time of day. Trials lasted weeks to months, so the effects of taking it for years are unknown.

NR vs NMN in one paragraph

Both NMN and nicotinamide riboside (NR) are building blocks your body can use to make NAD+. For a fuller comparison, read NMN vs NR and our nicotinamide riboside entry.

Side effects, interactions and who should check first

In the trials above, NMN was generally well tolerated at the doses studied, and a 2026 pooled review found no increase in side effects or liver enzyme markers [12]. But the trials were small and short.

The EU safety opinion for one NMN product noted effects on reproductive organs in a 90-day rat study, and it did not cover pregnant or breastfeeding women [14].

Who should check with a doctor or pharmacist first

Check with a doctor or pharmacist first if you:

• take any regular medicine. We did not find human studies testing NMN alongside medicines, so interactions are unknown rather than ruled out
• are pregnant, breastfeeding or trying to conceive, or are under 18
• have a long-term health condition (such as diabetes, or liver or kidney problems), or have had cancer. NAD+ pathways are involved in many body processes, and there is no good human data for these groups.

Can you buy NMN? What this site does and does not link to (information only)

Availability varies by country; not authorized for sale in the UK or EU yet [14][15].

This site does not link to NMN products, and we don’t name or price any. If you’re interested in raising NAD+, nicotinamide riboside (NR) is a related NAD+ building block, and our best NR supplement guide explains how we choose NR products. This information is for reference only, not a recommendation to buy.

FAQ

What is NMN?

NMN (nicotinamide mononucleotide) is a popular “longevity” supplement. It is a building block your body can use to make NAD+, a molecule involved in energy in your cells. Human trials reliably show that it raises a blood marker called NAD, but most of the exciting results come from mice [1][2][4][5].

Does NMN work?

Human trials reliably show that NMN raises a blood marker called NAD, but they have not shown clear, lasting health benefits [3][4][5][6][11]. Walking-speed results were small and mixed [4][6][7], and pooled trials found no clear benefit for glucose or blood fats [11]. We rate the evidence D.

How much NMN per day?

The most common trial dose was 250 mg a day for 6 to 12 weeks [3][4][6][7][8], and one trial tested 300 to 900 mg a day for 60 days [5]. These are amounts used in studies, not recommendations, and trials lasted weeks to months, so long-term effects are unknown.

Who should not take NMN?

Check with a doctor or pharmacist first if you take any regular medicine, are pregnant, breastfeeding or trying to conceive, are under 18, have a long-term condition such as diabetes or liver or kidney problems, or have had cancer. We found no good human data for these groups.

Can you take NMN with other supplements?

We found no human studies testing NMN alongside other supplements or medicines, so interactions are unknown rather than ruled out. The trials above tested NMN on its own or against placebo. If you take other supplements or any medicine, ask a doctor or pharmacist before adding NMN.

Related pages

• NMN vs NR
• What NAD+ is and why it matters
• Nicotinamide riboside
• Best NR supplement
• NAD+ injections explained
• Longevity supplements for beginners: where this fits in a beginner’s routine
• All supplements A-Z

Talk to your doctor

This page is for general information and is not medical advice. Speak to a doctor or pharmacist before starting any supplement, especially if you are pregnant or breastfeeding, take any medicine, or have a health condition.

References

We cite only studies and official pages we checked against PubMed, the publisher or the agency’s own site. The A to E evidence grades are explained in our editorial policy. See also our medical disclaimer and affiliate disclosure.

1. Mills KF, Yoshida S, Stein LR, et al. Long-term administration of nicotinamide mononucleotide mitigates age-associated physiological decline in mice. Cell Metab. 2016. PubMed · DOI
2. Yoshino J, Mills KF, Yoon MJ, et al. Nicotinamide mononucleotide, a key NAD(+) intermediate, treats the pathophysiology of diet- and age-induced diabetes in mice. Cell Metab. 2011. PubMed · DOI
3. Yoshino M, Yoshino J, Kayser BD, et al. Nicotinamide mononucleotide increases muscle insulin sensitivity in prediabetic women. Science. 2021. PubMed · DOI
4. Igarashi M, Nakagawa-Nagahama Y, Miura M, et al. Chronic nicotinamide mononucleotide supplementation elevates blood nicotinamide adenine dinucleotide levels and alters muscle function in healthy older men. NPJ Aging. 2022. PubMed · DOI
5. Yi L, Maier AB, Tao R, et al. The efficacy and safety of β-nicotinamide mononucleotide (NMN) supplementation in healthy middle-aged adults: a randomized, multicenter, double-blind, placebo-controlled, parallel-group, dose-dependent clinical trial. Geroscience. 2023. PubMed · DOI
6. Morifuji M, Higashi S, Ebihara S, et al. Ingestion of β-nicotinamide mononucleotide increased blood NAD levels, maintained walking speed, and improved sleep quality in older adults in a double-blind randomized, placebo-controlled study. Geroscience. 2024. PubMed · DOI
7. Kim M, Seol J, Sato T, et al. Effect of 12-week intake of nicotinamide mononucleotide on sleep quality, fatigue, and physical performance in older Japanese adults: a randomized, double-blind placebo-controlled study. Nutrients. 2022. PubMed · DOI
8. Okabe K, Yaku K, Uchida Y, et al. Oral administration of nicotinamide mononucleotide is safe and efficiently increases blood nicotinamide adenine dinucleotide levels in healthy subjects. Front Nutr. 2022. PubMed · DOI
9. Liao B, Zhao Y, Wang D, et al. Nicotinamide mononucleotide supplementation enhances aerobic capacity in amateur runners: a randomized, double-blind study. J Int Soc Sports Nutr. 2021. PubMed · DOI
10. Katayoshi T, Uehata S, Nakashima N, et al. Nicotinamide adenine dinucleotide metabolism and arterial stiffness after long-term nicotinamide mononucleotide supplementation: a randomized, double-blind, placebo-controlled trial. Sci Rep. 2023. PubMed · DOI
11. Chen F, Zhou D, Kong AP, et al. Effects of nicotinamide mononucleotide on glucose and lipid metabolism in adults: a systematic review and meta-analysis of randomised controlled trials. Curr Diab Rep. 2024. PubMed · DOI
12. Yang W, Huang J, Tang Z, et al. Safety and metabolism-related outcomes of oral nicotinamide mononucleotide supplementation in adults: a systematic review and meta-analysis. Nutrients. 2026. PubMed · DOI
13. Wang JP, Wang L, Wang T, et al. Effects of nicotinamide mononucleotide supplementation on muscle and liver functions among the middle-aged and elderly: a systematic review and meta-analysis of randomized controlled trials. Curr Pharm Biotechnol. 2025. PubMed · DOI
14. EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA), Turck D, Bohn T, et al. Safety of beta-nicotinamide mononucleotide (β-NMN) pursuant to Regulation (EU) 2015/2283 and the bioavailability of nicotinamide from this source in the context of Directive 2002/46/EC. EFSA Journal. 2026;24(5):e10007. PubMed · DOI
15. Food Standards Agency. Regulated product application RP-2116, β-Nicotinamide Mononucleotide (status: in progress, risk assessment). data.food.gov.uk · European Commission. Novel food status consultation, nicotinamide mononucleotide, 11 October 2022. food.ec.europa.eu (accessed 1 November 2026)