Research Summary · LongevityStack Research Team · Published July 2026
NMN (nicotinamide mononucleotide) is the single most-searched compound in the longevity supplement category, and most of what’s written about it cites animal studies. Here’s what actually happens when you give it to humans, based on the largest published dose-response trial to date.
The trial
Yi et al. ran an 80-person, multicenter, double-blind, placebo-controlled trial in healthy middle-aged adults, published in GeroScience in December 2022. Participants took either a placebo or 300 mg, 600 mg, or 900 mg of NMN daily for 60 days. This is the largest dose-ranging human NMN trial published so far, and the first to test three doses against placebo in parallel.
What it found
- Blood NAD+ rose significantly at every dose versus both placebo and baseline, at both day 30 and day 60 (p ≤ 0.001). The increase was largest at 600 mg and 900 mg — 300 mg worked, but less.
- Six-minute walk distance improved in all three NMN groups versus placebo, at both day 30 and day 60, with the biggest gains at 600–900 mg.
- “Blood biological age” (measured with the Aging.Ai 3.0 calculator, an algorithmic estimate — not a validated clinical biomarker) increased in the placebo group over 60 days and stayed flat in every NMN-treated group.
- Insulin resistance (HOMA-IR) didn’t move. No statistically significant difference between any NMN dose and placebo — worth knowing, since NAD+ precursors are sometimes marketed on metabolic claims this trial didn’t support.
- Self-reported health (SF-36 survey) improved significantly across all treated groups versus placebo, with one exception (300 mg group at day 30).
- No safety issues were reported at any dose up to 900 mg/day over 60 days.
What it doesn’t show
This trial measured blood NAD+, a walk test, an algorithmic age estimate, and a subjective survey — not disease incidence, mortality, or long-term healthspan outcomes. Sixty days is short for a compound being marketed on decades-scale claims, and 80 participants, while large for this specific research area, is still a moderate sample. Raising a blood biomarker is not the same thing as proving it changes how long or how well someone lives — that link is still an open research question.
A disclosure worth knowing
Several of the trial’s authors are affiliated with companies in the NMN ingredient supply chain (Abinopharm, Huzhou Yihui Biotechnology, ABA Chemicals). That doesn’t invalidate the data — it was still a registered, blinded, placebo-controlled trial (ClinicalTrials.gov NCT04823260) — but it’s exactly the kind of thing we think you should be told plainly rather than have buried in a methods section.
For context: a second, independent trial
A separate 2021 trial from Washington University, published in Science, gave NMN to postmenopausal women with prediabetes for 10 weeks and found improved muscle insulin sensitivity and insulin signaling — a different population and a different outcome than the trial above, but independent evidence that NMN does something measurable in human metabolism, not just in mice.
Where this leaves our ranking
Our current NMN + Resveratrol pick is filed under “NAD+ proxy markers” for a reason — that’s what the human evidence actually supports right now: reliable increases in a blood biomarker associated with cellular energy metabolism, plus some early functional signals (walk distance, self-reported health), not a proven longevity outcome. See this week’s rankings for the current pick and dosing window, and how we review for the process behind it.
According to PubMed: Yi L, et al. “The efficacy and safety of β-nicotinamide mononucleotide (NMN) supplementation in healthy middle-aged adults.” GeroScience. 2022. DOI: 10.1007/s11357-022-00705-1. Yoshino M, et al. “Nicotinamide mononucleotide increases muscle insulin sensitivity in prediabetic women.” Science. 2021. DOI: 10.1126/science.abe9985.
This article is for informational purposes and is not medical advice. Talk to a physician before starting any supplement protocol. LongevityStack may earn a commission on products linked from this site — see our affiliate disclosure.