The most consistent finding across 25 published human NMN trials is that NMN raises blood NAD+ (11 trials reported higher levels), while muscle function, walking speed, sleep and insulin sensitivity were measured in fewer trials, with mixed results. To take 500mg a day, RGENR8 Pure NMN Pro is £27.99 for a 3-month supply (90 capsules) on your first order, which is 31p a day, then £34.99 every 3 months.
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NMN (nicotinamide mononucleotide, sometimes typed MNM) is a building block the body uses to make NAD+, a molecule cells use in energy metabolism. This table groups the 25 trials in our NMN Human Trials Dataset by what they measured, checked against PubMed on 10 October 2026. A trial appears in every row it measured something for.
| Outcome area and trials | Typical dose and length | What the authors reported | PubMed sources |
|---|---|---|---|
| Blood NAD+ 15 trials measured it; 11 reported higher levels | 250 to 900mg a day for 8 to 12 weeks, or 1,000 to 2,000mg for 8 days to 4 weeks | Higher in 11 (8 against placebo). Huang 2022: rise reported, gap over placebo not significant. Katayoshi 2023 and Morita 2022: no NAD+ result in the summaries we hold. Wakabayashi 2026: no difference between swallowed and sublingual NMN. | Yi 2023, Igarashi 2022, Okabe 2022, Morifuji 2024, Pencina 2023a, Pencina 2023b, Pencina 2025, Christen 2026, Yamane 2023, Yamaguchi 2024, Berven 2026, Huang 2022, Katayoshi 2023, Morita 2022 (DOI), Wakabayashi 2026 |
| Muscle and physical function 9 trials measured it; 5 reported a gain on at least one measure | Most often 250 to 300mg a day for 8 to 12 weeks (range 1 to 24 weeks) | Better than placebo on at least one measure in 5. No gain in Akasaka 2023 (grip strength, walking speed) or Pencina 2023b (strength, aerobic capacity). Yang 2026: the exercise-induced rise in muscle mitochondrial content seen on placebo did not occur with NMN. Huang 2022: no separate result in the summary we hold. | Liao 2021, Huang 2022, Igarashi 2022, Kim 2022, Akasaka 2023, Pencina 2023b, Yi 2023, Morifuji 2024, Yang 2026 |
| Metabolic markers 7 trials measured it | 250 to 900mg a day for 8 to 12 weeks; one trial at 2,000mg for 4 weeks | Mixed. Higher insulin-stimulated glucose disposal than placebo in 25 women with prediabetes (Yoshino 2021). Changes in some metabolic markers at 2,000mg a day for 28 days, with no difference in insulin sensitivity (Pencina 2023b). No difference in HOMA-IR (Yi 2023). Changes reported in HOMA-IR (Huang 2022), pulse wave velocity (Katayoshi 2023, not significant) and postprandial insulin (Yamane 2023, Yamaguchi 2024). | Yoshino 2021, Huang 2022, Pencina 2023b, Yi 2023, Katayoshi 2023, Yamane 2023, Yamaguchi 2024 |
| Sleep and fatigue 4 trials recorded it; 2 reported a difference from placebo | 250mg a day for 8 to 12 weeks, plus single doses in Irie 2020 | Drowsiness and sit-to-stand time changed, most in the afternoon NMN group (Kim 2022). Two sleep questionnaire scores better than placebo, as secondary outcomes (Morifuji 2024). Sleep was a safety check only in Irie 2020 and Yamaguchi 2024. | Kim 2022, Morifuji 2024, Irie 2020, Yamaguchi 2024 |
| Other 6 trials measured it | 100 to 1,250mg a day, from a single dose to 13 weeks | Blood-cell markers in 8 men, no placebo group (Niu 2021). Before-and-after changes in blood markers and a self-rated skin score, no placebo group (Morita 2022). No change in body-awareness scores after one dose (Zhao 2026). Open-label, no control group, adults with a platelet disorder (Li 2026). Safety studies (Irie 2020, Fukamizu 2022). | Irie 2020, Niu 2021, Fukamizu 2022, Morita 2022 (DOI), Li 2026, Zhao 2026 |
Source: NMN Human Trials Dataset (CC BY 4.0). Results are what the authors reported, in short.
Eleven of the 15 trials that measured NAD+ reported higher levels with NMN. In Yi 2023, 80 adults took 300, 600 or 900mg a day and blood NAD was higher in every NMN group at days 30 and 60. In Christen 2026, 67 adults took 1,000mg for 14 days, and NMN and NR raised NAD+ by a similar amount. This is the finding behind "supports NAD+ levels". Background: Why NAD+ matters as we age and The cellular case for NMN.
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Nine trials measured strength, walking, stepping or aerobic capacity, and five reported better results than placebo on at least one measure. Yi 2023 reported a longer six-minute walk distance. Liao 2021, in 48 recreational runners, reported higher oxygen uptake at the ventilatory thresholds on 600 and 1,200mg, while VO2max did not change. Akasaka 2023 followed 14 older men for 24 weeks on 250mg and found no gain. More on this: Recovery, mitochondria, and morning runs.
Seven trials looked at insulin, glucose, body weight, blood pressure or arterial stiffness, and the results point in different directions. Yoshino 2021 used a clamp test after 10 weeks of 250mg. Pencina 2023b gave 30 overweight or obese adults 2,000mg for 28 days, a higher dose and a shorter course than most trials. Related reading: NAD+ and metabolic health and Heart, vessels, and the role of NAD+.
Four trials recorded sleep or tiredness, and two reported a difference from placebo, both in older adults taking 250mg a day for 12 weeks. Kim 2022 had 108 participants aged 65 and over. Morifuji 2024 had 60 older adults. Its sleep results were secondary outcomes, and its main stepping test showed no difference. Background: Sleep quality and the body's overnight maintenance. All the energy-related trials: Does NMN help with energy?
Six trials measured things that fit no other row, and four of the six had no control group. Niu 2021 had 8 men, Morita 2022 had 16 completers and Li 2026 had 25 adults with a platelet disorder. For skin, see Skin ageing and cellular repair.
NMN has no GB novel food authorisation yet. The application, RP-2116, is at risk assessment with the Food Standards Agency, and you can follow it on the FSA register. More: Is NMN legal in the UK?
RGENR8 Pure NMN Pro is one 500mg capsule of beta-NMN a day: at least 99% purity, one ingredient, no fillers or binders, in a vegan HPMC shell. It is made to GMP-equivalent standards, and an independent accredited lab tests every batch (certificate of analysis on request). 500mg sits inside the 250 to 2,000mg range the trials used. The 3-month plan is £27.99 for 90 capsules on your first order, with WELCOME20 applied at checkout (31p a day, £0.62 a gram), then £34.99 every 3 months. A single bottle of 30 is £24.95. UK delivery is free, and unopened bottles have a 14-day money-back guarantee. Pure NMN Pro supports healthy cell function and may support overall vitality and well-being. Other brands are compared in Best NMN supplement UK 2026: the main brands compared.
The most consistent finding in 25 published human trials is higher blood NAD+, reported in 11 of the 15 trials that measured it, at 250 to 2,000mg a day. Muscle function, walking speed, sleep and insulin sensitivity were measured in fewer trials with mixed results, so no particular effect can be promised.
NMN (nicotinamide mononucleotide, sometimes typed MNM) is a building block the body uses to make NAD+, a molecule cells use in energy metabolism. Taken by mouth, it raised blood NAD+ in 11 of the 25 human trials we checked.
Blood NAD+ was higher by the end of the course in the 11 trials that reported it, which ran from 8 days to 12 weeks. Trials that measured walking, sleep or drowsiness ran 6 to 24 weeks, most often 12, so there is no date by which to expect a particular feeling. Full timing guide: How long does NMN take to work? What 25 human trials show.
The trials used doses from 100mg to 2,000mg, and 14 of the 25 used 250mg or 300mg. RGENR8 Pure NMN Pro is one 500mg capsule a day. The doses trial by trial are in How much NMN should I take per day?
It depends what you want from it. If you want to support your NAD+ levels as part of a healthy routine, the human trials back that measurement. If you want a particular result by a particular date, the trials give no basis for that. Is NMN worth taking? What 25 human trials found, and what it costs has a checklist.
If you are pregnant, breastfeeding, taking medication or managing a health condition, check with your GP or pharmacist before taking any supplement.
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