Supplements

NMN (Nicotinamide Mononucleotide)

Updated · 24 sources · Editorial policy

NMN (nicotinamide mononucleotide) is a small molecule the body uses to make NAD+, a coenzyme that every cell needs for energy metabolism, DNA repair and gene regulation. It is sold as an oral dietary supplement, often promoted as an “NAD+ booster,” and a pharmaceutical-grade form called MIB-626 is in drug development.

Two facts matter most. First, human trials consistently show that oral NMN raises NAD+ levels in blood, but its effects on muscle, metabolism and physical performance have been small, mixed or absent in meta-analyses. Second, its US legal status has changed: in 2022 FDA said NMN could not be sold as a dietary supplement, and in September 2025 FDA reversed that position.

This page covers NMN. The coenzyme itself and the closely related precursor have their own pages: NAD+ and NR (nicotinamide riboside). This page summarizes what clinical trials, meta-analyses and FDA documents report. It is for education only and is not medical advice.

Property Detail
Class NAD+ precursor; nucleotide form of vitamin B3 (nicotinamide)
Chemistry C₁₁H₁₅N₂O₈P, 334.22 g/mol; the β form (β-NMN) is the one sold and studied
Route Oral capsules, tablets and powders
Doses in human trials Single doses of 100–500 mg; 250–2,000 mg/day for 2–24 weeks
Half-life No human plasma half-life published; in mice, plasma NMN returned to baseline within 15 min of an oral dose
Key mechanism fact Converted to NAD+ in tissues; in cell studies it is broken down outside cells before uptake
US status Dietary supplement ingredient (new dietary ingredient). FDA excluded it in 2022 and reversed that on September 29, 2025
Drug development MIB-626 (Metro International Biotech), an investigational NMN drug
WADA Not named on the 2026 Prohibited List

What it is

NMN is a nucleotide: nicotinamide (a form of vitamin B3) linked to a ribose sugar and a phosphate group (PubChem). In the body, cells make it from nicotinamide and then join it with ATP to form NAD+. NMN availability is described as a rate-limiting step in mammalian NAD+ production (Yoshino et al., Science 2021).

Interest in NMN comes from animal work. Tissue NAD+ falls with age, and raising it with precursors improves several age-related problems in rodents (see the NAD+ page for the human data on NAD+ decline). In the best-known mouse study, normal mice given NMN in their drinking water at 100 or 300 mg/kg/day for 12 months, from 5 to 17 months of age, gained less weight with age. They also showed better energy metabolism, insulin sensitivity, plasma lipids and eye function, with no obvious toxicity (Mills et al., Cell Metab 2016). These are mouse results and do not show that NMN does the same in people.

NMN and NR are close relatives. NR is NMN without the phosphate group. The two are often studied side by side, and human trials of both appear in the same meta-analyses.

How it works in the body

Absorption and uptake

Most NMN pharmacokinetic data come from animals and cell studies:

  • In mice, plasma NMN rose steeply 2.5 minutes after an oral dose of 300 mg/kg, rose further at 5–10 minutes, and was back to baseline at 15 minutes. Labeled NMN appeared as NAD+ in the liver within 10 minutes and in muscle by 30 minutes (Mills et al., 2016).
  • In human cells in culture, nucleotides such as NMN and NAD+ did not enter cells intact. They were first broken down outside the cell into smaller precursors (nicotinamide and its nucleoside, NR), which cells then used to rebuild NAD+ (Nikiforov et al., J Biol Chem 2011).

Human pharmacokinetics

No human study has published a plasma half-life for NMN. What human studies show is that oral NMN is used and broken down quickly:

Study Design Main pharmacokinetic finding
Irie et al., 2020 Single doses of 100, 250 and 500 mg in 10 healthy men; 5 h follow-up Plasma levels of two nicotinamide breakdown products (2PY and 4PY) rose with dose
Pencina et al., 2023 32 overweight or obese adults aged 55–80; MIB-626 1,000 mg once or twice daily vs placebo for 14 days Blood NMN exposure (AUC) 1.7 and 3.7 times baseline; dose-related rises in blood NAD+; very little NMN excreted unchanged in urine
Yoshino et al., 2021 250 mg/day for 10 weeks Muscle NAD+ content did not change, but muscle levels of NAD+ breakdown products rose, suggesting faster NAD+ turnover

So oral NMN reliably raises NAD+ and its metabolites in blood, but a higher blood level does not necessarily mean higher NAD+ inside muscle.

Regulatory status

2022: FDA says NMN is excluded from the supplement definition

Federal law has a “race to market” rule (section 201(ff)(3)(B) of the Food, Drug, and Cosmetic Act). A substance cannot be sold as a dietary supplement if it was first authorized for investigation as a new drug, with substantial clinical trials begun and made public, before anyone marketed it as a supplement or food.

  • May 16, 2022. FDA acknowledged a new dietary ingredient notification (NDIN) for NMN filed by SyncoZymes (FDA response, 2025).
  • October 11, 2022. In a letter to Inner Mongolia Kingdomway about its NMN notification, FDA wrote that NMN is authorized for investigation as a new drug. FDA concluded that NMN “was not marketed as a dietary supplement, except unlawfully” before that authorization, and so “may not be marketed as or in a dietary supplement” (FDA letters, NDI 1259). The letter cited registered trials of MIB-626 in COVID-19 with kidney injury, Alzheimer’s disease and Friedreich’s ataxia.
  • November 4, 2022. FDA sent supplemental letters explaining its reasoning and applied the same position to the other firms that had filed NMN notifications. FDA said it could not disclose the date NMN was first authorized for investigation as a drug. It also said that NMN sold as a supplement in Japan did not count as US marketing.

2023–2025: petitions, a lawsuit and a reversal

  • March 2023. The Natural Products Association (NPA) and the Alliance for Natural Health USA filed a citizen petition asking FDA to reverse its position. The Council for Responsible Nutrition (CRN) filed a separate petition in May 2023 (FDA response, 2025).
  • August 28, 2024. NPA sued FDA in federal court in Washington, DC (case 1:24-cv-02479) (court docket).
  • September 29, 2025. FDA granted the NPA/ANH petition in part. FDA said it no longer believes the earlier supplement marketing had to be lawful to count. It stated that it “is aware of evidence that NMN was marketed as a dietary supplement in the United States as early as 2017,” before the drug authorization. FDA therefore concluded that NMN is not excluded from the dietary supplement definition (FDA response, Docket FDA-2023-P-0872). It answered the CRN petition the same day (FDA response, Docket FDA-2023-P-1867).
  • December 2, 2025. FDA set aside its 2022 letters and sent new letters acknowledging earlier NMN notifications, including those from Inner Mongolia Kingdomway and SyncoZymes (FDA letter to Kingdomway; FDA letter to SyncoZymes). The Kingdomway notification covers products for adults providing no more than 400 mg NMN per day.

What the reversal does and does not mean

  • NMN is still a new dietary ingredient. It was not marketed in the US before October 15, 1994, so supplement makers must file a premarket safety notification unless they use an ingredient already covered by one (FDA response, 2025).
  • An acknowledgment is not a safety finding. FDA’s 2025 letters repeat that accepting a notification “does not constitute a finding by FDA” that the ingredient is safe. FDA can still act against NMN products that are unsafe, adulterated or misbranded.
  • The drug program continues. FDA confirmed that NMN and MIB-626 have the same chemical structure. MIB-626 remains an investigational drug, not an approved one.

What the research shows

Human trials of NMN are small (usually 10–100 people), short (2–24 weeks), and often funded or co-authored by NMN manufacturers. Most enrolled healthy or overweight middle-aged and older adults.

Blood NAD+ levels

Raising blood NAD+ is the most consistent finding:

  • 250 mg/day for 12 weeks raised whole-blood NAD+ in healthy older men (Igarashi et al., NPJ Aging 2022).
  • 300, 600 and 900 mg/day for 60 days all raised blood NAD+ more than placebo (all p ≤ 0.001) in 80 healthy adults aged 40–65. The highest levels were with 600 and 900 mg (Yi et al., GeroScience 2023).
  • In 42 adults hospitalized with COVID-19 and kidney injury, MIB-626 1 g twice daily raised mean blood NAD+ from 16.0 to 42.6 µg/mL over 14 days. Kidney injury, inflammation and disease severity markers did not differ from placebo (Pencina et al., FASEB Bioadv 2025).

Insulin sensitivity and metabolism

The most cited trial randomized 25 postmenopausal women with prediabetes and overweight or obesity to 250 mg/day NMN (n = 13) or placebo (n = 12) for 10 weeks (Yoshino et al., Science 2021):

Outcome NMN result
Muscle insulin sensitivity (glucose disposal during a clamp test) +25% ± 7% from baseline; no change on placebo
Liver and fat-tissue insulin sensitivity No change
Body weight, body fat, liver fat No change
Fasting glucose, insulin, lipids, blood pressure No change

A published comment pointed out that liver fat at baseline differed sharply between groups: 6.3% in the NMN group vs 14.8% on placebo (Brenner, Science 2021). The authors replied that muscle insulin sensitivity, the main outcome, was the same in both groups at baseline (Klein & Yoshino, Science 2021).

A 28-day trial of MIB-626 1,000 mg twice daily in 30 overweight or obese adults aged 45 and older found modest falls compared with placebo (Pencina et al., JCEM 2023):

  • body weight: −1.9 kg (95% CI −3.3 to −0.5);
  • diastolic blood pressure: −7.0 mmHg (95% CI −13.4 to −0.6);
  • LDL cholesterol: −18.7 mg/dL (95% CI −31.9 to −5.6).

Insulin sensitivity, liver fat, abdominal fat, muscle strength and aerobic capacity did not change. Several authors were affiliated with the drug’s developer, Metro International Biotech.

Pooled analyses are less encouraging:

Meta-analysis Trials Finding
Yang et al., Nutrients 2026 15 RCTs; 250–2,000 mg/day for 14 days to 24 weeks No significant effect on body weight, BMI, fasting glucose, HbA1c, lipids or systolic blood pressure; a small fall in diastolic pressure
Zhang et al., Nutrients 2026 10 RCTs, 349 participants Diastolic pressure −2.15 mmHg (95% CI −3.68 to −0.61); no significant change in systolic pressure overall

Muscle and physical performance

Results here are mixed and mostly null in pooled data:

  • Older men. 250 mg/day for 12 weeks gave only “nominally significant” improvements in gait speed and left grip strength and no change in body composition (Igarashi et al., 2022). Of 42 men randomized, 20 completed the full 12 weeks.
  • Middle-aged adults. Six-minute walk distance rose more than placebo at 300, 600 and 900 mg/day, with no further gain from 600 to 900 mg (Yi et al., 2023). The trial was fully funded by two NMN suppliers.
  • Amateur runners. 48 trained runners aged 27–50 took placebo or 300, 600 or 1,200 mg/day for 6 weeks while training. Power at the ventilatory thresholds rose more at 600 and 1,200 mg than on placebo, but VO2max (maximal aerobic capacity) and peak power did not change in any group (Liao et al., J Int Soc Sports Nutr 2021).
  • Meta-analysis in adults over 60. NMN had no significant effect on skeletal muscle index, grip strength, gait speed or chair-stand time. The authors concluded the evidence does not support NMN or NR for preserving muscle mass and function (Prokopidis et al., J Cachexia Sarcopenia Muscle 2025).

No trial has tested whether NMN increases muscle mass or strength in young, resistance-trained people.

Disease trials

Medical use is still experimental. In a single-arm phase 1/2 trial, 25 adults with immune thrombocytopenia (a low platelet count caused by the immune system) that had not responded to or depended on steroids took 450 mg NMN twice daily for 2 weeks. Five patients (20%) met the main platelet-response goal (Li et al., Nat Med 2026). There was no placebo group.

Side effects and risks

Short-term safety

Trials up to 24 weeks have not found a clear safety signal:

  • 1,250 mg once daily for 4 weeks in 31 healthy adults aged 20–65 caused no changes beyond normal variation in blood counts, chemistry, urine tests or body composition, and no serious adverse events (Fukamizu et al., Sci Rep 2022).
  • Single doses up to 500 mg caused no symptoms or changes in heart rate, blood pressure or body temperature. Bilirubin rose and creatinine, chloride and glucose fell slightly, all within normal ranges (Irie et al., 2020).
  • MIB-626 at 2,000 mg/day was well tolerated for 14–28 days, with adverse events similar to placebo (Pencina et al., 2023; Pencina et al., JCEM 2023).
  • In the 2026 meta-analysis, NMN did not increase overall, serious or system-specific adverse events, withdrawals, or the liver enzymes ALT and AST (Yang et al., 2026).

Unknowns

  • Long-term safety. No published trial has lasted longer than 24 weeks. The meta-analysis authors note the evidence is dominated by small, short trials, which limits conclusions about rare adverse events.
  • Who was studied. Trials enrolled mostly healthy or metabolically at-risk adults. We found no controlled data in pregnancy, children, or people with cancer, liver disease or kidney disease (apart from the short COVID-19 trial).
  • Industry involvement. Many trials were funded or co-authored by NMN manufacturers or the developer of MIB-626.

Quality and contamination

Supplement labels for NMN are not reliable. A 2024 study bought 18 NMN products online or in pharmacies and measured their content (Sandalova et al., GeroScience 2024):

  • two capsule products contained no quantifiable NMN;
  • a liposomal powder contained 86% less NMN than claimed;
  • others ranged from about 11% above to about 66% below the label.

An FDA acknowledgment of an NMN notification is not a finding that the ingredient, or any product made with it, is safe or not adulterated (FDA letter to Kingdomway).

Use in sport

NMN is not named on the WADA 2026 Prohibited List (WADA 2026 Prohibited List). As with any supplement, the label-accuracy problems above mean a product may not contain what it claims.

Key takeaways

  • An NAD+ precursor sold as a supplement. NMN is one step away from NAD+. A pharmaceutical form, MIB-626, is also being developed as a drug.
  • It raises blood NAD+. This is the most consistent human finding, at doses of 250–2,000 mg/day. Higher blood NAD+ has not reliably led to higher muscle NAD+.
  • Clinical benefits are small or unproven. A 10-week trial found better muscle insulin sensitivity in women with prediabetes. Meta-analyses found no effect on muscle mass, strength, glucose or lipids, and only a diastolic blood pressure fall of about 2 mmHg.
  • Short-term safety looks acceptable. Trials up to 24 weeks, with doses up to 2,000 mg/day, found no clear increase in adverse events. Long-term data do not exist.
  • The legal status changed. FDA said in 2022 that NMN could not be sold as a supplement, then reversed that on September 29, 2025, after finding US supplement sales dating back to 2017.
  • Products vary widely. In one test of 18 products, two contained no measurable NMN.

Sources

  1. National Center for Biotechnology Information. Nicotinamide Mononucleotide, PubChem CID 14180. PubChem.
  2. Food and Drug Administration, Center for Food Safety and Applied Nutrition. Letter (October 11, 2022) and supplemental response letter (November 4, 2022) to Inner Mongolia Kingdomway Pharmaceutical Limited regarding NDI 1259, β-nicotinamide mononucleotide (NMN). Docket FDA-2022-S-0023-0051. regulations.gov.
  3. Food and Drug Administration, Human Foods Program. Response letter to Natural Products Association and Alliance for Natural Health USA, citizen petition on the regulatory status of β-nicotinamide mononucleotide. September 29, 2025. Docket FDA-2023-P-0872-2754. regulations.gov.
  4. Food and Drug Administration, Human Foods Program. Response letter to the Council for Responsible Nutrition. September 29, 2025. Docket FDA-2023-P-1867-0007. regulations.gov.
  5. Food and Drug Administration, Human Foods Program. Reinstatement response letters regarding NDI 1259 (Inner Mongolia Kingdomway Pharmaceutical Limited) and NDI 1247 (SyncoZymes (Shanghai) Co., Ltd.), β-nicotinamide mononucleotide. December 2025. regulations.gov (NDI 1259); regulations.gov (NDI 1247).
  6. Natural Products Association v. Food and Drug Administration, No. 1:24-cv-02479 (D.D.C., filed August 28, 2024). CourtListener.
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  24. World Anti-Doping Agency. The 2026 Prohibited List. WADA 2026 Prohibited List.