NMN: how much per day, when to take it, and for how long?
· by VEXTA Team
How much per day?
The only human trial comparing several NMN doses is Yi 2023 (GeroScience, DOI 10.1007/s11357-022-00705-1): a randomised, multicentre, double-blind, placebo-controlled trial in 80 healthy middle-aged adults across four arms — placebo, 300 mg, 600 mg and 900 mg of NMN daily for 60 days.
Blood NAD rose significantly in all three NMN arms, at day 30 and day 60, against both placebo and baseline (p ≤ 0.001). The highest concentrations were seen at 600 and 900 mg. In plain terms: 300 mg is enough to move the marker, 600 mg moves it further, and 900 mg adds no clear gain over 600 mg.
Above 900 mg per day there is no published human data at all. Any higher dose is extrapolation, not literature.
What time of day?
This is the most-asked question and the one the literature is quietest on. Published trials — Yi 2023 included — administer NMN once daily without comparing schedules. No randomised trial pits a morning dose against an evening one.
The argument usually made for mornings rests on the circadian rhythm of NAMPT, the rate-limiting enzyme of the NAD salvage pathway, whose expression oscillates over 24 hours. That is a plausible mechanistic hypothesis, not a clinical finding. In practice: pick the time you will actually keep to for two months — adherence outweighs timing.
How long before anything is measurable?
Thirty days is enough to move blood NAD in Yi 2023. Functional endpoints take longer: distance covered in the six-minute walk test improved significantly against placebo at both day 30 and day 60 (p < 0.01), with the longest distances in the 600 and 900 mg arms.
One result deserves quoting exactly as published: blood biological age increased in the placebo group and remained unchanged in every NMN group over 60 days (p < 0.05). What was measured is therefore not rejuvenation but relative stabilisation over a two-month window.
A sensible evaluation window is 8 to 12 weeks, deciding in advance what you will observe.
Where NMN stands regulatorily
NMN has no finalised novel food authorisation in the European Union. Switzerland and the United Kingdom have validated dossiers. This explains why availability differs sharply by market and why most of the trade runs online.
NR (nicotinamide riboside) sits in the opposite position: EU novel food status obtained in 2017, so a clear regulatory frame. NR also has documented brain NAD elevation by magnetic resonance spectroscopy (Brakedal 2022, DOI 10.1016/j.cmet.2022.02.001). If regulatory clarity is your main criterion, that is the precursor to choose.
Tolerability
In Yi 2023, all 80 participants completed the trial without protocol violation, no safety signal was found across adverse events, laboratory and clinical measures, and supplementation was described as well tolerated up to 900 mg per day over 60 days.
That data covers healthy middle-aged adults over two months. It covers neither pregnancy, nor breastfeeding, nor concurrent medication. Seek medical advice before starting if any of those apply.