What it is
NMN (nicotinamide mononucleotide) is a direct precursor to NAD+, taken orally. NAD+ is a coenzyme, and NMN is studied for supporting NAD+ levels, which decline with age. Human trials to date are small and short.
In the PeptidesAI encyclopedia it is categorized under immune. Its status as a US dietary supplement was disputed until the FDA reversed its position in September 2025.
How it's thought to work
NMN is converted to NAD+ via the salvage pathway, which replenishes the coenzyme required for sirtuin activity, PARP-mediated DNA repair and mitochondrial energy metabolism.
What the research says
Small human trials report increased blood NAD+ levels and some metabolic measures, with clinical benefit still unclear. A 10-week randomized, placebo-controlled trial in postmenopausal women with prediabetes who were overweight or obese reported that NMN increased muscle insulin sensitivity and insulin signaling. A 60-day randomized trial in 80 healthy middle-aged adults reported higher blood NAD concentrations than placebo. A 2026 meta-analysis of randomized trials found that broad metabolic benefits were not evident and called for larger and longer trials.
NMN is not an approved drug. In letters dated September 29, 2025, the FDA concluded that NMN is not excluded from the dietary supplement definition, reversing its earlier position. Availability and labeling vary by market.
Reported side effects
In short human trials, mild gastrointestinal upset, headache and occasional flushing are reported. A 2026 meta-analysis of short-term randomized trials found no clear increase in adverse events, but long-term human safety data is limited.
Form
NMN is taken by mouth as capsules or powder, so it is not reconstituted.
Important notes
NMN is not FDA-approved as a drug. The FDA reversed its earlier position on NMN as a dietary supplement in September 2025, and availability and labeling vary by market.
Sources
- Nicotinamide mononucleotide increases muscle insulin sensitivity in prediabetic women. Yoshino M et al. Science, 2021. Human trial
- 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 L et al. Geroscience, 2023. Human trial
- Safety and Metabolism-Related Outcomes of Oral Nicotinamide Mononucleotide Supplementation in Adults: A Systematic Review and Meta-Analysis. Yang W et al. Nutrients, 2026. Review
- FDA Declares Nicotinamide Mononucleotide Is a Dietary Supplement. Venable LLP, 2025. Legal analysis
Frequently asked questions
These questions cover the same ground as the sections above, in a shorter format.
What is NMN?
Nicotinamide mononucleotide, a direct precursor to NAD+ taken orally and studied for supporting NAD+ levels, which decline with age.
How is NMN thought to work?
It is converted to NAD+ via the salvage pathway, replenishing the coenzyme needed for sirtuin activity, PARP-mediated DNA repair and mitochondrial energy metabolism.
What does the research on NMN say?
Small, short human trials report increased blood NAD+ and some metabolic measures, but clinical benefit is still unclear. NMN is not an approved drug.
What are the reported side effects of NMN?
Short human trials report mild gastrointestinal upset, headache and occasional flushing; long-term human safety data is limited.
The full entry, plus the calculator
The PeptidesAI app has the complete encyclopedia entry for NMN (Nicotinamide Mononucleotide) — one of 70 compounds covered — plus the reconstitution calculator, a dose log and reminders. Free to download on iPhone.
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