NMN (Nicotinamide mononucleotide)

Pharmacology & Research

NMN (β-nicotinamide mononucleotide) is a nucleotide and the immediate biosynthetic precursor to NAD+, the coenzyme that drives cellular energy metabolism and fuels the sirtuin and PARP enzyme families. Because tissue NAD+ falls with age, NMN is sold on the premise that topping it back up will slow ageing and sharpen metabolism — a hypothesis that, unusually for a longevity supplement, now rests on a growing set of human randomised trials rather than mouse data alone. The consistent finding across those trials is that oral NMN reliably raises blood NAD+, but the downstream clinical benefits are small, inconsistent, or absent once you demand hard outcomes and placebo controls. Almost all trials are short (2–24 weeks), modestly sized (typically 10–80 people), and skewed toward older or metabolically at-risk adults, so a benefit that shows up in a 65-year-old may not generalise to a healthy 35-year-old. Form and dose matter less here than for a mineral — most trials used generic oral β-NMN at 250–1250 mg/day — but the gap between “moved the biomarker” and “changed how you age” is the whole story.

1. Raising blood NAD+

This is the one thing NMN unambiguously does. Across trials, oral β-NMN raises whole-blood NAD+ and its metabolites in a dose-dependent way: a 60-day dose-ranging RCT in 80 middle-aged adults (placebo, 300, 600, 900 mg/day) confirmed dose-dependent NAD+ elevation ^{6Reference 6Yi et al. · 2023RCTThe efficacy and safety of β-nicotinamide mononucleotide (NMN) supplementation in healthy middle-aged adults — [RCT, dose-ranging]View study →}, and a 14-day RCT of a microcrystalline formulation (MIB-626, 1000 mg once or twice daily) raised blood NMN 1.7- to 3.7-fold above baseline with a corresponding rise in NAD+ ^{13Reference 13Pencina et al. · 2023RCTMIB-626, an oral formulation of a microcrystalline unique polymorph of β-nicotinamide mononucleotide, increases circulating NAD and its metabolome in middle-aged and older adults — [RCT]View study →}. Other older-adult trials that tracked NAD+ alongside clinical endpoints likewise saw it climb with 250 mg/day dosing ^{8Reference 8Morifuji et al. · 2024RCTIngestion of β-nicotinamide mononucleotide increased blood NAD levels, maintained walking speed, and improved sleep quality in older adults — [RCT]View study →}. The key limitation is conceptual, not statistical: raising a blood biomarker is a mechanism-of-action check, not a health outcome, and the trials that measured clinical endpoints alongside NAD+ generally failed to show them move in step.

Gap: every positive trial here reports a surrogate marker; none demonstrates that the extra NAD+ translates into a clinical benefit.

2. Blood pressure

The most credible clinical signal comes from cardiovascular measures. A 2026 systematic review and meta-analysis pooled 10 RCTs (11 arms, 349 participants) and found NMN produced a statistically significant but modest reduction in resting diastolic pressure (−2.15 mmHg; 95% CI −3.68 to −0.61), with systolic pressure falling significantly only in the subgroup aged 60 and over (−3.94 mmHg; 95% CI −7.06 to −0.82) ^{12Reference 12Zhang et al. · 2026Meta-analysisEffects of nicotinamide mononucleotide supplementation on blood pressure: a systematic review and meta-analysis of RCTs — [meta-analysis]View study →}. This is consistent with a single physiologic RCT (MIB-626, 30 overweight/obese adults ≥45 y) that reported a −7.0 mmHg diastolic difference versus placebo alongside reductions in body weight and LDL cholesterol ^{7Reference 7Pencina et al. · 2023RCTNicotinamide adenine dinucleotide augmentation in overweight or obese middle-aged and older adults: a physiologic study — [RCT]View study →}. Effects are small, seen mainly in older or at-risk groups, and the authors themselves frame them as preliminary and hypothesis-generating.

Gap: the effect is modest, concentrated in older adults, and awaits confirmation in large, long-term trials powered for cardiovascular endpoints rather than office blood pressure.

3. Aerobic capacity & physical performance

A 6-week, four-arm RCT in 48 amateur runners (300, 600, 1200 mg/day vs placebo) found that oxygen uptake and power at the ventilatory thresholds improved more in the medium- and high-dose groups than placebo — but VO2max itself, O2-pulse, and peak power did not change, and the effect was interpreted as better muscle O2 utilisation during training rather than a raw fitness gain ^{4Reference 4Liao et al. · 2021RCTNicotinamide mononucleotide supplementation enhances aerobic capacity in amateur runners — [RCT]View study →}. In older adults, a 12-week RCT at 250 mg/day found no difference in the primary stepping test, though the NMN group had a significantly shorter 4-m walking time as a secondary outcome ^{8Reference 8Morifuji et al. · 2024RCTIngestion of β-nicotinamide mononucleotide increased blood NAD levels, maintained walking speed, and improved sleep quality in older adults — [RCT]View study →}. Against these, a 24-week RCT in older diabetic men with impaired performance found no difference in grip strength or walking speed ^{16Reference 16Akasaka et al. · 2023RCTEffects of nicotinamide mononucleotide on older patients with diabetes and impaired physical performance — [RCT, null]View study →}, and a 2025 meta-analysis on muscle mass and function found no significant effect on skeletal muscle index, grip strength, or gait speed ^{11Reference 11Prokopidis et al. · 2025Meta-analysisThe effect of nicotinamide mononucleotide and riboside on skeletal muscle mass and function: a systematic review and meta-analysis — [meta-analysis]View study →}.

Gap: benefits appear only in specific groups (trained or frail older adults) and mostly on secondary endpoints; primary performance outcomes and the muscle meta-analysis are null.

4. Insulin sensitivity & metabolic markers

The headline positive study is a 10-week RCT in postmenopausal prediabetic women with overweight/obesity, where NMN (250 mg/day) increased insulin-stimulated glucose disposal measured by hyperinsulinemic–euglycemic clamp and enhanced skeletal-muscle insulin signalling (AKT/mTOR phosphorylation) versus placebo ^{3Reference 3Yoshino et al. · 2021RCTNicotinamide mononucleotide increases muscle insulin sensitivity in prediabetic women — [RCT]View study →}. That result is real but narrow — a deficiency-and-risk population, a mechanistic endpoint — and it has not generalised. Two 2024–2025 meta-analyses of RCTs (8 trials/342 adults; and 12 trials/513 adults) found no significant effect of NMN on fasting glucose, fasting insulin, HbA1c, HOMA-IR, or the lipid panel, while confirming the NAD+ rise; both flagged substantial risk of bias in the underlying trials ^{9,10Reference 9Chen et al. · 2024Meta-analysisEffects of nicotinamide mononucleotide on glucose and lipid metabolism in adults: a systematic review and meta-analysis of RCTs — [meta-analysis]View study →Reference 10Zhang et al. · 2025Meta-analysisEfficacy of oral nicotinamide mononucleotide supplementation on glucose and lipid metabolism for adults: a systematic review with meta-analysis of RCTs — [meta-analysis]View study →}. A physiologic RCT in overweight/obese adults similarly found no change in insulin sensitivity or ectopic fat ^{7Reference 7Pencina et al. · 2023RCTNicotinamide adenine dinucleotide augmentation in overweight or obese middle-aged and older adults: a physiologic study — [RCT]View study →}.

Gap: the one positive clamp study is in a specific at-risk group; pooled RCT evidence in broader, mostly healthy adults shows no metabolic benefit.

5. Sleep quality & fatigue

Sleep and fatigue signals come from secondary endpoints. A 12-week RCT in 108 older Japanese adults (250 mg/day, timed morning vs afternoon) found afternoon NMN produced the largest effect on lower-limb function (5-times sit-to-stand, d = 0.72) and reduced drowsiness (d = 0.64), suggesting a timing-dependent benefit ^{5Reference 5Kim et al. · 2022RCTEffect of 12-week intake of nicotinamide mononucleotide on sleep quality, fatigue, and physical performance in older Japanese adults — [RCT]View study →}. A separate 12-week RCT in older adults reported improved subjective sleep quality alongside maintained walking speed ^{8Reference 8Morifuji et al. · 2024RCTIngestion of β-nicotinamide mononucleotide increased blood NAD levels, maintained walking speed, and improved sleep quality in older adults — [RCT]View study →}. These are modest, questionnaire-based, timing-sensitive findings in older populations, and a dedicated multicentre insomnia RCT is registered but not yet reported.

Gap: results rest on subjective secondary endpoints in older adults, are sensitive to dose timing, and lack confirmation from a trial designed primarily around sleep.

Mechanisms

Target / pathway	Effect	Relevant to
NAD+ biosynthesis (salvage pathway)	NMN → NMNAT → NAD+ ↑	All applications — the shared upstream mechanism
Sirtuins (SIRT1–7)	↑ activity (NAD+-dependent deacylases)	Metabolic, vascular, putative anti-ageing
Slc12a8 NMN transporter	Direct NMN uptake (shown in mouse intestine; disputed) 15Reference 15Grozio et al. · 2019AnimalSlc12a8 is a nicotinamide mononucleotide transporter — [mechanistic, mouse]View study →	Absorption/bioavailability rationale
Endothelial / vascular NAD+	↑ eNOS signalling, ↓ arterial stiffness (trend)	Blood pressure
Skeletal-muscle NAD+ / mitochondrial function	↑ O2 utilisation, insulin signalling	Aerobic capacity, insulin sensitivity

Pharmacokinetics

Oral NMN is absorbed rapidly; plasma NMN metabolites rise within minutes to hours, and single doses of 100–500 mg produce dose-related increases in nicotinamide-pathway metabolites without acute clinical changes ^{14Reference 14Irie et al. · 2020Clinical trialEffect of oral administration of nicotinamide mononucleotide on clinical parameters and nicotinamide metabolite levels in healthy Japanese men — [clinical trial]View study →}. Whether NMN is absorbed intact or first cleaved to nicotinamide riboside/nicotinamide at the gut wall remains contested: a mouse NMN transporter (Slc12a8) was reported in 2019 ^{15Reference 15Grozio et al. · 2019AnimalSlc12a8 is a nicotinamide mononucleotide transporter — [mechanistic, mouse]View study →} but the finding was challenged, so the exact route of human uptake is unresolved. Regardless of route, blood NAD+ rises dose-dependently and plateaus over days to weeks of daily dosing ^{6,13Reference 6Yi et al. · 2023RCTThe efficacy and safety of β-nicotinamide mononucleotide (NMN) supplementation in healthy middle-aged adults — [RCT, dose-ranging]View study →Reference 13Pencina et al. · 2023RCTMIB-626, an oral formulation of a microcrystalline unique polymorph of β-nicotinamide mononucleotide, increases circulating NAD and its metabolome in middle-aged and older adults — [RCT]View study →}. There is no established elimination half-life for NMN itself as a longevity input — it is consumed into the NAD+ pool — and the practically relevant question is the steady-state NAD+ elevation from daily dosing, not single-dose kinetics. Newer formulations (microcrystalline MIB-626, sublingual, nano-delivery) are being tested to improve tissue delivery, but none has demonstrated a clinical-outcome advantage over generic oral NMN.

Clinical trials

NMN has an active and growing registered-trial footprint — dozens of small RCTs completed since 2020, several ongoing (including a registered multicentre insomnia trial), and one line of industry-sponsored development around the microcrystalline MIB-626 formulation, which has since been tested in hospitalised COVID-19/acute-kidney-injury patients as well. Because NMN is a commodity molecule, most trials are small, investigator- or supplement-industry-funded, and short; there is no large, long-duration outcomes trial.

Completed	Planned/ongoing	Terminated	Preclinical
~15–20 human RCTs	several (incl. insomnia, cardiometabolic)	few	hundreds (rodent/in vitro)

Last checked: July 2026.

Dietary Sources

NMN occurs naturally in small amounts in a range of foods, but dietary intake is orders of magnitude below the doses used in supplements. Reported natural NMN contents are in the low milligrams — or fractions of a milligram — per kilogram of food, so ordinary eating supplies at most a few milligrams a day, versus the 250–900 mg used in trials. Foods most often cited as sources include edamame and other soy products, broccoli, cabbage, cucumber, avocado, and tomato, with smaller amounts in raw beef and shrimp.

Food	Approx. NMN content	Notes
Edamame / soybean	~0.5–2 mg per 100 g	Among the richer plant sources
Broccoli	~0.2–1 mg per 100 g	Cruciferous vegetable
Cucumber (seed)	~0.5–1.5 mg per 100 g	Concentrated in seed
Avocado	~0.3–1.5 mg per 100 g
Cabbage, tomato	~0.1–0.7 mg per 100 g
Raw beef, shrimp	~0.06–0.4 mg per 100 g	Animal sources, lower

Values are approximate and drawn from limited food-analysis literature; NMN content varies with ripeness, storage, and cooking.

The body also makes NMN endogenously from dietary niacin-family vitamins (nicotinamide, nicotinamide riboside) via the NAD+ salvage pathway, so NMN is not an essential dietary nutrient — there is no deficiency state and no recommended intake. The practical implication: no realistic diet delivers a “supplemental” NMN dose, which is precisely why the supplement exists — but it also means NMN sits outside the usual “correct a dietary shortfall” logic that justifies most vitamins and minerals.

Dosage & Intake

Human trials have used roughly 150–1250 mg/day, with 250–900 mg/day the most common range; single-dose safety work has gone up to 500 mg and repeated-dose safety work up to 1250 mg/day. These are doses studied in research, not a personal recommendation.

A few practical notes from the trial literature:

• No established optimal dose. Blood NAD+ rises dose-dependently, but because clinical outcomes rarely track the biomarker, there is no dose proven to deliver a health benefit. Higher is not demonstrably better for outcomes.
• Timing may matter for some effects. In one older-adult trial, afternoon dosing outperformed morning dosing for lower-limb function and drowsiness ^{5Reference 5Kim et al. · 2022RCTEffect of 12-week intake of nicotinamide mononucleotide on sleep quality, fatigue, and physical performance in older Japanese adults — [RCT]View study →} — a single finding, not a rule.
• Daily dosing builds a steady state. NAD+ elevation accumulates over days to weeks of consistent daily intake rather than from a single dose.
• Formulation. Generic oral β-NMN was used in most trials; microcrystalline (MIB-626), sublingual, and nano-delivery forms exist but none has shown a clinical-outcome advantage, so paying a premium for a “high-absorption” form is not evidence-backed.
• Not an essential nutrient, so there is no RDA/AI to meet and no established Tolerable Upper Intake Level to stay under.
• Regulatory status. In the United States, the FDA has taken the position that NMN is excluded from the dietary-supplement definition (it was investigated as a drug), so its legal status as a supplement is contested and product availability may vary.

Safety

NMN has looked reassuringly benign in the short human trials conducted so far. A randomised, double-blind, placebo-controlled trial of 1250 mg/day for up to 4 weeks in 31 healthy adults found no changes beyond normal physiological variation and no serious adverse events ^{2Reference 2Fukamizu et al. · 2022RCTSafety evaluation of β-nicotinamide mononucleotide oral administration in healthy adult men and women — [RCT, safety]View study →}, and single oral doses of 100–500 mg caused no significant changes in heart rate, blood pressure, oxygen saturation, or laboratory parameters ^{14Reference 14Irie et al. · 2020Clinical trialEffect of oral administration of nicotinamide mononucleotide on clinical parameters and nicotinamide metabolite levels in healthy Japanese men — [clinical trial]View study →}. Across the trial base, reported side effects are infrequent and mild (occasional digestive upset). The 2024 systematic review of RCTs likewise reported no serious adverse effects ^{1Reference 1Wen et al. · 2024Systematic reviewImproved physical performance parameters in patients taking nicotinamide mononucleotide (NMN): a systematic review of randomized control trials — [systematic review]View study →}.

The honest caveats are about what has not been studied:

• Duration. The longest trials run about 24 weeks; NMN is marketed for lifelong daily use, and there is no long-term safety data at all.
• Populations. Trials skew toward healthy or metabolically at-risk middle-aged and older adults. Effects in the young, the frail, or people with significant disease are largely uncharacterised.
• Drug interactions — not formally assessed. No dedicated interaction studies exist. Because NMN feeds the NAD+/sirtuin/PARP axis, theoretical interactions with drugs affecting NAD+ metabolism cannot be excluded, but none has been characterised in humans.
• Renal/hepatic impairment — not studied. No dosing data in organ impairment.
• Regulatory status. In the United States, the FDA has taken the position that NMN is excluded from the dietary-supplement definition (it was investigated as a drug), so its legal status as a supplement is contested and product availability may vary.

Pregnancy & lactation

Verdict: avoid. There are no human safety data on NMN during pregnancy or lactation, and no established upper limit. Absence of reported harm is not evidence of safety — it reflects that the studies have not been done. NMN should not be used during pregnancy or breastfeeding.

References