2 min readLongevity & Biological Age
NAD+ boosters: what nicotinamide riboside and NMN actually do in humans, according to the trials
A randomised trial found that 12 weeks of NMN raised blood NAD+ levels and modestly improved walking speed and sleep quality in older adults — but the wider body of human trials on NAD-precursor supplements is far more mixed than the marketing around them suggests.
Part 20 of 23This article is part of the Longevity & Biological Age guideMorifuji M, Higashi S, Ebihara S, Nagata M. "Ingestion of β-nicotinamide mononucleotide increased blood NAD levels, maintained walking speed, and improved sleep quality in older adults in a double-blind randomized, placebo-controlled study." GeroScience, 2024; 46(5):4671-4688. View study →
NAD+ boosters — nicotinamide riboside (NR) and nicotinamide mononucleotide (NMN) — are among the most heavily marketed longevity supplements, often framed as reversing cellular aging. The actual human trial evidence is more modest, and worth separating from the marketing claim by claim.
What a real randomised trial found
A 2024 double-blind, placebo-controlled trial gave older adults daily NMN for 12 weeks and confirmed it did raise blood NAD+ levels, as intended. On functional outcomes, the NMN group maintained walking speed over the study period (versus a decline in the placebo group) and reported improved sleep quality. Other human RCTs add supporting detail: a 2021 Science trial found NMN improved skeletal-muscle insulin sensitivity in prediabetic women, and a 2023 trial found a related NMN-based compound was safe and altered some physiologic markers over a longer dosing period.
The honest caveats
These are short trials (weeks to months) in small-to-moderate samples, measuring intermediate markers — walking speed, insulin sensitivity, blood NAD+ levels — not lifespan, disease incidence, or a validated slowing of biological aging. No human trial has shown NAD-precursor supplementation extends lifespan or reverses aging by any of the accepted biological-age clocks. "Raises blood NAD+ levels" and "slows aging" are not the same claim, and current evidence only firmly supports the first.
Where this leaves the decision
The signal is real but incremental: modest functional benefits in older adults over months, not a proven anti-aging intervention. It is a reasonable thing to discuss with a clinician if you’re over 60 and interested in the walking-speed and sleep-quality signal specifically — it is not yet evidence for a general population dosing recommendation.
Misi’s Longevity Lab prioritises the levers with the deepest human evidence base — sleep, VO2max, resistance training, protein intake — before newer supplement categories, and will keep tracking this literature as larger, longer trials report out.
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