5
Selected publications
Four randomized trials and one metabolic systematic review, chosen for distinct questions and important limitations.
Research review | Oral nicotinamide mononucleotide
NMN
What human trials actually measure.
Oral NMN can raise blood NAD-related measurements. Whether those changes lead to better health is a separate question. Here is what the human trials report, including the results that did not improve.
The central distinction
NAD+
A biological response is not a longevity outcome. Selected trials found changes in blood NAD, muscle insulin sensitivity or physical tests. A review of eight trials found no significant pooled improvement in routine glucose or lipid measures. [5]
Ingredient research, not a clinical trial of Neurogan products. No human lifespan extension is established by these sources.
Selected publications from 2021 to 2024. Oral supplements only. All summaries, visuals and references work without JavaScript.
A real human evidence base, with a narrow reach.
This is a selected research review, not a complete systematic search of every NMN publication.
8 RCTs
In the metabolic review
342 participants as reported by the review. Individual trials below overlap this evidence base and are not extra participants. [5]
14 days
to 12 weeks
to 12 weeks
Short-term exposures
The range in the metabolic review. This is not evidence of safety or benefit over years. [5]
What is NMN?
Nicotinamide mononucleotide is a precursor used in the body's production of nicotinamide adenine dinucleotide, or NAD+. NAD participates in energy metabolism and other cell processes. That essential role explains scientific interest, but it does not prove that taking more precursor improves health. [5]
NMN and NAD+ are different molecules. This page evaluates taking NMN by mouth, not taking NAD+ itself. It also does not treat results with other NAD precursors as NMN evidence.
Follow the measurement, not just the molecule.
Three different questions often get compressed into the phrase “NAD support.”
Does blood chemistry change?
Observed in selected trials. Whole-blood NAD+ rose in the older-men study. The dose-ranging study measured serum total NAD+ plus NADH. [2] [3]
Does a physiological test improve?
Some early signals. Muscle insulin sensitivity, selected exercise thresholds and walking tests showed findings worth further study, alongside null endpoints. [1] [2] [3] [4]
Does health improve over time?
Not established here. These studies do not demonstrate longer life, disease prevention or reversal of aging. Routine glucose and lipid pooling was negative. [5]
“Blood NAD” is not one interchangeable measurement
Whole blood contains cells. Serum is the liquid remaining after clotting. NAD+ is the oxidized form; NADH is the reduced form. A serum assay that combines the two cannot be relabeled as intracellular NAD+ in muscle, brain or every cell. Results measured in different compartments should not be placed on one “NAD boost” scale. [2] [3]
Positive findings and null findings belong together.
A result map, not a benefit score. Labels describe the reported endpoint and do not show the size of an effect.
| Study | Reported signal | Null result or essential boundary |
|---|---|---|
| Prediabetic women [1] | Muscle insulin sensitivityClamp-measured glucose disposal increased after NMN, not placebo. | Specific muscle physiology, not demonstrated diabetes prevention. |
| Older men [2] | Whole-blood NAD+Exploratory gait and left-grip findings. | Body composition: no significant effectOnly 20 valid week-12 participants. |
| Middle-aged adults [3] | Serum total NAD and walkingNAD+ plus NADH increased; walking-test changes favored NMN. | HOMA-IR: no significant differenceBiological-age calculator unchanged with NMN, not reversed. |
| Recreational runners [4] | Selected exercise thresholdsStronger findings at 600 and 1,200 mg with training. | VO2max: no significant differenceNot evidence of faster race performance. |
| Metabolic review [5] | Blood NAD-related increases in five of eight trials. | No significant pooled metabolic benefitFasting glucose, insulin, HbA1c, HOMA-IR and lipid profile. |
Why the muscle trial and the review can both be right
A clamp measures how the body handles glucose during a controlled insulin infusion. Fasting glucose, HbA1c and HOMA-IR ask different questions. A change in muscle insulin sensitivity in a small prediabetes study does not require a corresponding change in routine blood tests across mostly healthy adults. [1] [5]
Why “not significant” does not mean “exactly zero”
Small trials can miss effects. A null finding means the analysis did not establish a difference under its statistical criteria, not that every possible effect has been excluded. Equally, a small p-value is not a measure of how much someone benefits.
The studied amount is only part of the comparison.
Daily NMN exposure in the four selected trials. Each dot is a tested active-dose group; placebo is omitted.
No bar or dot represents efficacy, absorption or a recommended amount.
06001,200 mg/day
250 mg/day
250 mg/day
300, 600, 900 mg/day
300, 600, 1,200 mg/day
The broader review included up to 2,000 mg/day, but that highest exposure lasted only 14 days. The longer studies cannot establish the long-term safety of that dose. Matching milligrams does not match formulation, population, outcome or duration. [5]
Read the trials in context.
Each summary keeps the sample, dose, formulation, duration and limitations next to the result.
5 publications shown
01
Yoshino et al. · Science · 2021
Muscle insulin sensitivity in prediabetes
- Design
- Randomized double-blind placebo-controlled trial
- Population / sample
- 25 postmenopausal women with overweight or obesity and prediabetes
- Daily dose
- 250 mg/day
- Formulation
- Oral NMN, not a liposomal formula
- Duration
- 10 weeks
What the study found
Insulin-stimulated glucose disposal increased after NMN but not placebo. Muscle insulin-signaling proteins also responded. The clamp test measures glucose handling under controlled insulin exposure, not everyday blood sugar control.
What did not improve, or remains unproven
The result does not establish diabetes prevention, weight loss or broad metabolic improvement. Routine glucose and lipid results across trials were not significantly improved in the pooled review [5].
View publication ↗ · Reference [1] · DOI: 10.1126/science.abe9985
02
Igarashi et al. · npj Aging · 2022
Blood NAD and physical function in older men
- Design
- Randomized double-blind placebo-controlled parallel trial
- Population / sample
- 42 healthy men aged 65 or older randomized; only 20 had valid week-12 data
- Daily dose
- 250 mg/day
- Formulation
- Conventional oral NMN
- Duration
- 6 and 12 weeks
What the study found
Whole-blood NAD+ and related metabolites increased. Gait speed and left-hand grip had nominally significant improvements, meaning they were exploratory signals that need confirmation.
What did not improve, or remains unproven
Body composition did not significantly change. The paper did not find a significant overall effect on right-hand grip. These are not findings of increased muscle mass or prevention of age-related disability.
View publication ↗ · Reference [2] · DOI: 10.1038/s41514-022-00084-z
03
Yi et al. · GeroScience · 2023 (online 2022)
Dose-ranging trial in middle-aged adults
- Design
- Multicenter randomized double-blind placebo-controlled dose-ranging trial
- Population / sample
- 80 healthy adults aged 40 to 65; 20 in each of three NMN arms and placebo
- Daily dose
- 300, 600 or 900 mg/day
- Formulation
- AbinoNutra NMN powder in 150 mg capsules; swallowed with water
- Duration
- 60 days
What the study found
Serum total NAD (NAD+ plus NADH) increased versus placebo at days 30 and 60 in all NMN groups (p ≤ 0.001). Six-minute walking-distance increases favored NMN at both visits (p < 0.01). SF-36 self-reported health scores also favored NMN at day 60.
What did not improve, or remains unproven
HOMA-IR did not differ significantly from placebo at day 60. A calculator-derived biological-age value stayed unchanged with NMN while the placebo value increased. That is not evidence of reversed aging.
View publication ↗ · Reference [3] · DOI: 10.1007/s11357-022-00705-1
04
Liao et al. · Journal of the International Society of Sports Nutrition · 2021
Exercise thresholds in recreational runners
- Design
- Randomized double-blind placebo-controlled four-arm trial with exercise
- Population / sample
- 48 recreational runners: 40 men and 8 women; 12 participants per arm
- Daily dose
- 300, 600 or 1,200 mg/day
- Formulation
- Oral NMN powder in two daily doses, alongside exercise training
- Duration
- 6 weeks
What the study found
At 600 and 1,200 mg/day, selected oxygen-uptake and power measures at ventilatory thresholds improved more than control. Everyone followed training sessions of 40 to 60 minutes, five to six times per week.
What did not improve, or remains unproven
VO2max, oxygen pulse and peak power did not show significant between-group differences. A higher ventilatory threshold is not the same as a higher maximum aerobic capacity or a faster race time.
View publication ↗ · Reference [4] · DOI: 10.1186/s12970-021-00442-4
05
Chen et al. · Current Diabetes Reports · 2024
Pooled glucose and lipid results
- Design
- Systematic review and random-effects meta-analysis of 8 RCTs
- Population / sample
- 8 randomized trials reporting 342 participants in total, mainly relatively healthy middle-aged or older adults; 49% female
- Daily dose
- 250 to 2,000 mg/day across included trials
- Formulation
- Oral NMN; formulations varied across trials
- Duration
- 14 days to 12 weeks
What the study found
The review found no statistically significant pooled benefit for fasting glucose, fasting insulin, HbA1c, HOMA-IR or lipid profile. Five of the eight trials reported a rise in blood NAD-related measurements, showing that a biomarker response can coexist with null metabolic outcomes.
What did not improve, or remains unproven
The HOMA-IR analysis was close to, but did not meet, the conventional significance threshold (p = 0.06). That is not a confirmed benefit. The review does not rule out every possible effect in every population.
View publication ↗ · Reference [5] · DOI: 10.1007/s11892-024-01557-z
From a research dose to a product label.
A factual comparison of the supplied product listings. These are not dosing recommendations or proof of finished-product efficacy.
No exact-product trial is identified in the selected evidence
These publications studied NMN ingredients and specific research preparations, not the Neurogan products listed below. Similar milligrams do not prove similar absorption or outcomes. Check the current Supplement Facts and serving instructions because product listings can change.
| Product | Amount in supplied listing | What the research comparison can tell you |
|---|---|---|
| NMN Capsules 500MG ↗ | 500 mg per capsule | Falls between several tested doses, but 500 mg was not an arm in the four trials summarized here. A nearby dose does not establish the same result. |
| NMN Capsules 900mg ↗ | 900 mg per one-capsule serving | Matches a daily amount in the 60-day dose-ranging trial, not its finished capsule or a proven long-term regimen. The trial used six 150 mg AbinoNutra capsules. [3] |
| Liposomal NMN Capsules ↗ | 700 mg of liposomal NMN per serving, as described in the listing | The selected trials do not compare this liposomal product with conventional NMN. A liposomal label alone does not establish superior absorption, clinical benefit or equivalence of active NMN amount. |
| NMN Drops ↗ | 20,000 mg total NMN per bottle; suggested use 1 mL daily | Bottle total is not a daily dose. The supplied listing does not specify bottle volume or mg per mL, so daily milligrams cannot be calculated from that text. Swallowed use is the relevant comparison here; under-the-tongue equivalence is not established. |
| NMN Powder ↗ | 60 g total powder; suggested use one level scoop | The listing does not give a scoop mass. Total package weight and a purity statement do not identify a daily NMN dose. Research used specified milligram amounts, including powder in the runners trial. [4] |
| NMN + Resveratrol Capsules ↗ | 1,200 mg combined per two capsules; a stated 1:1 blend | The stated ratio implies 600 mg NMN plus 600 mg resveratrol per two capsules, or 300 mg of each per capsule. Suggested use says one capsule daily, not the two-capsule serving. These selected NMN-alone trials do not establish the blend’s effects or synergy. |
Product descriptions above are catalog context, not scientific citations. Milligram figures for the blend are arithmetic from the listed 1:1 ratio, not an independent assay. No superiority of drops, liposomal delivery or a resveratrol blend has been demonstrated by these five sources.
What remains unknown matters.
A short trial can describe short-term tolerability. It cannot establish the safety or benefit of years of use.
Safety: reassuring observations, limited follow-up
The 60-day dose-ranging trial reported no safety issues at 300, 600 or 900 mg/day based on adverse-event monitoring, laboratory testing and clinical measures. The older-men trial also reported acceptable short-term tolerability. [2] [3]
The metabolic review found no severe adverse effects in the included human trials, but noted a tendency toward more reported adverse events at doses of 1,000 mg/day or higher, regardless of whether they were related to NMN. That observation is not a quantified risk estimate. [5]
Small samples and brief exposure can miss uncommon or delayed harms. Long-term high-dose safety remains uncertain.
Who should be especially cautious?
The evidence here does not establish safety during pregnancy or breastfeeding, in children, or in people with major medical conditions. Medication interactions and cancer-related outcomes are not adequately resolved by these trials.
Discuss supplementation with a qualified clinician if you take prescription medicines, have an active medical condition or are receiving cancer treatment. An endogenous molecule is not automatically risk-free as a supplement.
What this evidence cannot promise
Longer life, reversed biological aging, diabetes prevention, dependable weight loss, universal exercise improvement or superior absorption from a particular retail delivery system.
How this review was prepared
Five existing research sources were selected for relevance to oral NMN, study design and contrasting endpoints. The metabolic review and three trial full texts were checked, along with the primary abstract for the prediabetes trial; its dose and sample were cross-checked in the review. This is not an exhaustive or continuously updated literature search. The review’s search ended May 31, 2023. Its participant total is reported as published, and overlapping trial populations are not added together.
The dose graphic shows only exposure. The result map is qualitative. Neither assigns a numerical evidence score or turns statistical significance into a benefit percentage.
The questions behind the headlines.
Plain-language answers to common interpretation problems.
Does raising NAD+ mean NMN extends life?
No. A biomarker can show that a biological pathway responds without establishing longer survival or better long-term health. None of the selected human trials demonstrates lifespan extension.
Is 900 mg better than 500 mg?
The selected studies do not provide a direct comparison of these two retail products. The dose-ranging trial compared 300, 600 and 900 mg/day for 60 days and does not establish a universally optimal dose.
Does the biological-age result mean people became younger?
No. In the dose-ranging study, the calculator-derived value stayed unchanged in NMN groups while it rose in placebo. This is neither demonstrated age reversal nor a measured change in lifespan.
What do HOMA-IR, HbA1c and VO2max mean?
HOMA-IR estimates insulin resistance from fasting glucose and insulin. HbA1c reflects blood glucose exposure over preceding months. VO2max is the maximum rate of oxygen uptake during exercise. None is interchangeable with the muscle clamp test or a blood NAD measurement.
How should I read a p-value?
A p-value describes how incompatible the observed data are with a specified no-effect statistical model, given its assumptions. It is not the probability that the treatment works, and it does not tell you the size or practical importance of a benefit.
References you can check.
Independent numbering for this NMN review. Product listings above are separate from the scientific evidence.
- [1]Nicotinamide mononucleotide increases muscle insulin sensitivity in prediabetic women.
Yoshino et al. · Science · 2021. DOI: 10.1126/science.abe9985. PMID: 33888596.
PubMed ↗ · Publisher / DOI ↗ · Back to study summary - [2]Chronic nicotinamide mononucleotide supplementation elevates blood nicotinamide adenine dinucleotide levels and alters muscle function in healthy older men.
Igarashi et al. · npj Aging · 2022. DOI: 10.1038/s41514-022-00084-z. PMID: 35927255.
PubMed ↗ · Publisher / DOI ↗ · Back to study summary - [3]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.
Yi et al. · GeroScience · 2023 (online 2022). DOI: 10.1007/s11357-022-00705-1. PMID: 36482258.
PubMed ↗ · Publisher / DOI ↗ · Back to study summary - [4]Nicotinamide mononucleotide supplementation enhances aerobic capacity in amateur runners: a randomized, double-blind study.
Liao et al. · Journal of the International Society of Sports Nutrition · 2021. DOI: 10.1186/s12970-021-00442-4. PMID: 34238308.
PubMed ↗ · Publisher / DOI ↗ · Back to study summary - [5]Effects of Nicotinamide Mononucleotide on Glucose and Lipid Metabolism in Adults: A Systematic Review and Meta-analysis of Randomised Controlled Trials.
Chen et al. · Current Diabetes Reports · 2024. DOI: 10.1007/s11892-024-01557-z. PMID: 39531138.
PubMed ↗ · Publisher / DOI ↗ · Back to study summary