NMN Human Clinical Trials: What the Studies Show

Vitality Supplements · Ingredient Guide

NMN Human Clinical Trials

A plain-English, evidence-led summary of the published human NMN clinical trials — for each study, what dose was used, how long it ran, how many people took part, and what was measured. Most trials measured blood NAD+ levels, some added walking or physical measures, and several focused on safety and tolerability.

Last updated July 2026 · Written by Vitality Supplements Editorial Team · ~2,500 words · 10 min read
Food supplement information — not medical advice
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Quick answer
What do the human NMN clinical trials show?
NMN (nicotinamide mononucleotide) is a precursor the body uses to make NAD+. A growing set of human clinical trials — typically running 4 to 12 weeks at daily doses from 250 mg to about 900 mg — have mainly measured whether taking NMN raises blood NAD+ levels. Several report that it does, in a dose-related way, while also reporting that NMN was generally well tolerated at the doses studied. Some trials added physical measures such as walking tests. Trials are still relatively small and short, so this page describes what each study measured and reported — not what NMN will do for you. NMN is sold as a food supplement in the UK with no authorised health claims.
Key takeaways
  • Published human NMN trials have used daily doses roughly from 250 mg up to about 900 mg.
  • Most ran for 4 to 12 weeks, with participant numbers usually in the tens.
  • The most common primary measure was blood (whole-blood or serum) NAD+ level.
  • One 2023 trial reported blood NAD+ rose about +38% over 12 weeks at 1 g/day versus about +8% on placebo.
  • Some trials also measured physical performance such as a six-minute walk test.
  • Across the trials, NMN was generally reported as well tolerated; long-term data is still limited.
The evidence base

The human trials, in context

Interest in NMN comes from its role as a building block for NAD+, a coenzyme found in every cell. Much of the early work on NMN was done in cells and animals; the human evidence base is younger, smaller and still growing. The trials published so far are mostly randomised, placebo-controlled studies with participant numbers in the tens rather than the thousands, running for weeks rather than years.

The single most consistent thing these trials set out to answer is a pharmacological one: does taking oral NMN actually raise the amount of NAD+ measurable in the blood? That is a measurement, not a health outcome — it tells you the supplement is being absorbed and converted, not how a person will feel. Several trials report that blood NAD+ does rise, and that it tends to rise more at higher doses. Beyond that, individual studies have layered on additional measures such as walking tests, grip strength, aerobic capacity markers, sleepiness questionnaires and standard blood-safety panels.

Nearly every trial asks the same core question first: does blood NAD+ go up?

For the practical side of dosing, see our dedicated NMN dosage guide and our head-to-head on NMN 500mg vs 1000mg. If you are wondering about timescales, our companion page on how long NMN takes to work looks at the same trials through the lens of time.

At a glance

Key NMN trials compared

The table below summarises several well-known published human NMN trials. Figures are as reported by the studies; it is a simplified overview, not a complete list of all NMN research. Doses, durations and participant numbers vary, which is one reason results are not directly comparable.

Study (year) Participants Daily dose Duration Primary measure Key reported finding
Yi et al. (2023) 66 middle-aged adults 300, 600 or 900 mg 60 days Blood NAD+, walking, aerobic markers Blood NAD+ rose in a dose-related way; six-minute walk distance increased across dose groups vs placebo.
2023 RCT (1 g/day) ~80 adults 1,000 mg 12 weeks Whole-blood NAD+ Blood NAD+ reported up ~+38% over 12 weeks vs ~+8% on placebo.
Igarashi et al. (2022) Older men 250 mg 6-12 weeks NAD+ metabolism, physical measures NMN increased NAD+ metabolites; some muscle/physical measures assessed.
Yoshino et al. (2021) 25 postmenopausal women with prediabetes 250 mg 10 weeks Muscle insulin signalling Measured changes in muscle insulin-related markers; study reported it was well tolerated.
Liu et al. (2021) Recreational runners 300-1,200 mg 6 weeks Aerobic capacity (training) Assessed aerobic performance measures during exercise training at several doses.
Irie et al. (2020) 10 healthy men 100-500 mg (single) Single dose Safety, pharmacology Single oral doses were reported safe and well tolerated; measured metabolites and basic safety.

Figures summarised from published human trials and reflect what each study measured and reported, not a promise of any effect. Study designs, populations and measurement methods differ, so results should not be read as directly comparable. Full citations are on our research references page.

Reading the results

What the trials measured

To make sense of NMN research it helps to separate the different types of measurement the trials used. They are not all the same kind of evidence, and a change in a lab marker is not the same as a change in how someone feels or functions.

Blood NAD+ levels
The most common measure. Trials sampled whole-blood or serum NAD+ before and after supplementation to see whether oral NMN raised it. This shows absorption and conversion — a pharmacological readout, not a health outcome.
Physical / walking measures
Functional tests. Some studies added a six-minute walk test, grip strength or aerobic-capacity markers. These describe what was recorded in that group over the study window.
Metabolic markers
Blood chemistry. A few trials looked at insulin-related signalling or other metabolic markers. These are exploratory measures within small groups.
Safety & tolerability
Standard checks. Trials monitored liver and kidney panels, blood pressure, heart rate and reported side effects to assess whether NMN was well tolerated at the dose used.

The recurring pattern is that blood NAD+ tends to rise with NMN and tends to rise more at higher doses, while the broader functional measures are more mixed, come from smaller groups, and need larger and longer trials to interpret confidently. That is the honest state of the evidence in 2026: promising on the NAD+ measurement, early and limited on everything downstream of it.

A higher NAD+ reading on a lab sheet is a measurement — not a benefit you can promise a person.
Tolerability

Safety & tolerability in the trials

Across the published human trials, NMN has generally been reported as well tolerated at the doses studied, from single 100-500 mg doses up to 900 mg-1 g daily for several weeks. Studies that ran standard safety panels reported no consistent signal of harm to liver or kidney markers, blood pressure or heart rate over their study windows. This is reassuring within the limits of small, short trials, but it is not the same as long-term safety data, which does not yet exist at scale.

  • Doses studied — single doses of 100-500 mg and daily doses up to about 900 mg-1 g were used in the trials.
  • Duration — most trials ran a few weeks to 12 weeks; longer-term human data is limited.
  • Monitoring — trials tracked blood-safety panels, vital signs and reported side effects.
  • General finding — NMN was typically reported as well tolerated at the doses tested.
  • Not a substitute for advice — trial safety data does not replace speaking to a healthcare professional about your own situation.

A separate regulatory point worth knowing: in the UK, NMN's status as a food supplement is evolving and it is treated as a novel-food-sensitive ingredient. That is about how it is sold and regulated, not about the trial data itself. For quality and authenticity — a real issue in this category — see our guide on spotting genuine vs mislabelled NMN. Whatever the research shows, it only applies if the product actually contains what the label claims.

Common questions

NMN trials FAQ

Yes. Several randomised, placebo-controlled human trials have been published, typically with participant numbers in the tens, running from a single dose up to about 12 weeks. Most set out to measure whether oral NMN raises blood NAD+ levels, and some added physical or metabolic measures. They are still relatively small and short compared with medicines research.
A 2023 randomised controlled trial using 1 g per day for 12 weeks reported that whole-blood NAD+ rose by roughly +38% in the NMN group compared with about +8% on placebo. That figure describes a change in a blood measurement the study recorded — it is not a claim about how a person will feel. A separate 2023 trial by Yi and colleagues reported dose-related NAD+ increases at 300, 600 and 900 mg.
Across the studies, daily doses ranged roughly from 250 mg to about 900 mg-1 g, with some single-dose pharmacology studies at 100-500 mg. Higher doses tended to raise blood NAD+ more. For how this maps to products, see our 500mg vs 1000mg comparison and the general NMN dosage guide.
Mostly the trials measured objective markers — blood NAD+ levels, walking distance, aerobic markers and safety panels — rather than subjective wellbeing. Where questionnaires were used, results are early and from small groups. Because of that, and because NMN carries no authorised health claims in the UK, we describe only what was measured, not what you should expect to feel.
Within their limits, the trials generally reported NMN as well tolerated at the doses used, with no consistent adverse signal on the blood-safety panels and vital signs they monitored. This applies to short study windows of weeks to a few months; robust long-term human safety data does not yet exist. Always consult a healthcare professional before starting a supplement.
This page is a plain-English summary of what the main human NMN trials measured and reported. Our research references page is the underlying citation list with full study details. Use this page to understand the trials at a glance, and the references page to look up the sources.

NMN, done properly

Our Pure NMN 1000mg is UK-manufactured and independently batch tested, with a Certificate of Analysis available on request — so the NMN you take matches what the research studied.

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About the author. This guide was written and reviewed by the Vitality Supplements Editorial Team, a UK supplement manufacturer. Every batch we produce is independently tested by an ISO/IEC 17025-accredited laboratory, with a Certificate of Analysis available on request.

This article is for general information about food supplements and is not medical advice. It summarises what published research measured and does not make health claims. NMN is sold as a food supplement in the UK and carries no authorised health claims. Always consult a qualified healthcare professional before starting any supplement, particularly if you are under 18, pregnant, breastfeeding, taking medication or managing a health condition. References available on our research references page.