NMN: Human Trial Evidence and Regulatory Status

Overview and classification

NMN (nicotinamide mononucleotide) is a precursor of NAD+ and is used as a dietary supplement. [1] It has also been studied as an investigational drug. [2] Approval of NMN as a medicine: proper evidence not found in the sources read for this page (the FDA letter and trial reports). For background on NAD+, see NAD+ biology and its decline with age.

This page is education only. It gives no amounts and no advice to start or stop anything. Trial amounts are left out on purpose.

Evidence labels used: approved medicine, established, promising but limited, mixed, insufficient evidence, preclinical (cells or animals only), no good evidence of benefit, evidence of harm, marketing claim.

Animals versus people

Reviews report that in rodents, raising NAD+ was often linked to better metabolic, mitochondrial and inflammatory results, though effects varied. [3] That is preclinical evidence. The authors of a 2022 trial note that preclinical studies suggested NAD+ raising could ease aging-related disorders, but that human data were limited. [4] The sections below cover people only.

The main randomized trials

All of these are short (weeks, not years) and fairly small. Several were written by people employed by companies, which is noted below because it matters for how much weight to give them.

Two trials disagree on insulin sensitivity: it improved in the prediabetes trial and did not change in the 28-day trial of overweight adults. [5][9] Different people, designs and lengths may explain this; the evidence is mixed.

Pooled results

• Safety and metabolism. A 2026 meta-analysis of 15 randomized trials (10 in the safety analysis, lasting 14 days to 24 weeks) found NMN did not increase overall, serious or system-specific adverse events, nor liver enzymes. It found no significant effects on body weight, BMI, fasting glucose, HbA1c, lipid profiles or systolic blood pressure, and a slight fall in diastolic pressure. The authors said larger, longer trials must confirm efficacy and long-term safety. [1]
• Muscle in older adults. A 2025 meta-analysis found no significant effect of NMN on skeletal muscle index, grip strength, gait speed or the chair-stand test, and concluded current evidence does not support NMN or NR for preserving muscle mass and function in adults averaging over 60. [10]

Label for metabolic and physical-function benefits: promising but limited, with mixed results. Label for slowing aging or extending life in people: insufficient evidence.

Intravenous NMN

A 2026 systematic review found one nonrandomized intravenous NMN study that met its criteria, which mainly offered short-term safety and biomarker information. [3] A separate review called the human evidence for intravenous NAD+ or precursors sparse and preliminary, with reported effects including nausea, cramping, flushing and chest discomfort and no long-term safety data. [11] Label: insufficient evidence.

Regulatory status in the United States (read from the FDA)

• What changed. In a response to a citizen petition (docket FDA-2023-P-0872), the FDA concluded NMN is not excluded from the definition of a dietary supplement. [2] A law-firm summary confirms two letters dated September 29, 2025 and describes a reversal of the earlier position. [12]
• Why it had been excluded. The FDA had said in 2022 that NMN was excluded because it was authorized for investigation as a new drug and investigations were made public. The letter says that information, about a study product coded MIB-626 that has the same chemical structure as NMN, was available but had been overlooked at first. [2]
• Why the FDA changed its view. The agency revised how it reads a "race-to-market" provision and said it is aware of evidence that NMN was marketed as a dietary supplement in the US as early as 2017, before it was authorized for investigation as a drug. [2]
• What it does not mean. An acknowledged safety notification "does not constitute an independent finding by FDA" that the ingredient is safe. [2] More generally, supplement firms are responsible for evaluating safety and labeling before marketing, and the FDA can act against adulterated or misbranded products after they reach the market. [13]

The PDF's date line reads "2029," which looks like a typo. Other countries' rules were not verified for this page. Laws change, and this is not legal advice. See how supplements are regulated and supplement regulation by country.

Who should check first

Ask a clinician or pharmacist before using NMN if you are pregnant or breastfeeding, have diabetes, liver disease or another long-term condition, take medicines, or face surgery. Pregnancy and breastfeeding were not addressed in the sources read. Product quality varies; see product quality and contamination. For claim-reading help see NAD, NMN and longevity claims and NMN vs nicotinamide riboside.