{"ok":true,"entry":{"slug":"nad-precursors","kind":"supplement","name":"nad+ precursors (nmn, nr)","aliases":["nicotinamide mononucleotide","nicotinamide riboside","nad+","nmn","nr"],"brands_sg":["Holistic Way"],"class":"nad+ precursor (vitamin b3 family)","tags":["energy"],"use_for":"early human trials only — blood nad+ up; benefits unproven","use_after":"once a day · one trial favoured dosing after 18:00","use_duration":"the trial ran 12 weeks","take_with":"water · trials dosed before (nmn) or after (nr) breakfast","pros":["raises blood nad+ within 2 weeks (nr 100–1000 mg)","well tolerated in 8–12-wk trials up to 900 mg nmn","nr: fda gras 'no questions' 2016 + efsa safe at 300 mg"],"cons":["reviews: most clinical outcomes no better than placebo","no muscle-mass or function benefit shown in over-60s","nmn was barred from us supplements nov 2022–sep 2025"],"dose_note":"trials use 250–2,000 mg nmn a day (250 mg most common) or 100–2,000 mg nr, mostly for 6–12 weeks; efsa judged nr safe at 300 mg/day for healthy adults; meta-analyses find no consistent clinical benefit beyond raising blood nad+","dosage":{"ul":null,"unit":"mg","fda_dv":null,"rda_ai":null,"ul_status":"none_established","population":"general adult","hsa_max_daily":null},"ul_status":"none_established","sg_class":null,"cautions":["pregnant or breastfeeding — efsa caps nr at 230 mg/day","under 18 — trials are in middle-aged and older adults","prediabetes or diabetes — data mixed; ask your doctor first"],"clashes":[],"sources":[{"id":"yoshino2021","url":"https://europepmc.org/article/MED/33888596","label":"Nicotinamide mononucleotide increases muscle insulin sensitivity in prediabetic women (Yoshino et al., Science 2021)","quote":"10-week, randomized, placebo-controlled, double-blind trial … postmenopausal women with prediabetes who were overweight or obese. Insulin-stimulated glucose disposal … and skeletal muscle insulin signaling … increased after NMN supplementation but did not change after placebo treatment","accessed":"2026-08-27"},{"id":"igarashi2022","url":"https://europepmc.org/article/PMC/PMC9158788","label":"Chronic NMN supplementation elevates blood NAD+ and alters muscle function in healthy older men (Igarashi et al., npj Aging 2022)","quote":"We administered 250 mg NMN per day to aged men for 6 or 12 weeks … well tolerated and caused no significant deleterious effect … significantly increased the NAD+ and NAD+ metabolite concentrations. There were nominally significant improvements in gait speed and performance in the left grip test, which should be validated in larger studies; however, NMN exerted no significant effect on body composition","accessed":"2026-08-27"},{"id":"yi2023","url":"https://europepmc.org/article/PMC/PMC9735188","label":"Efficacy and safety of NMN in healthy middle-aged adults: dose-dependent RCT (Yi et al., GeroScience 2023)","quote":"80 middle-aged healthy adults … 60-day … once daily oral dosing of placebo, 300 mg, 600 mg, or 900 mg NMN … Blood NAD concentrations were statistically significantly increased among all NMN-treated groups … No safety issues … well tolerated … The HOMA-IR showed no statistically significant differences … take the capsules orally with water of ambient temperature once daily before breakfast","accessed":"2026-08-27"},{"id":"kim2022","url":"https://europepmc.org/article/PMC/PMC8877443","label":"Effect of 12-week NMN intake on sleep quality, fatigue and physical performance in older Japanese adults (Kim et al., Nutrients 2022)","quote":"108 participants … NMN (250 mg) or placebo was administered once a day for 12 weeks … The NMN_PM group demonstrated the largest effect size for 5-STS (d = 0.72) and drowsiness (d = 0.64). Overall, NMN intake in the afternoon effectively improved lower limb function and reduced drowsiness in older adults","accessed":"2026-08-27"},{"id":"martens2018","url":"https://europepmc.org/article/PMC/PMC5876407","label":"Chronic nicotinamide riboside supplementation is well-tolerated and elevates NAD+ in healthy middle-aged and older adults (Martens et al., Nat Commun 2018)","quote":"NR supplementation (500 mg, 2×/day) … is well tolerated and effectively stimulates NAD+ metabolism in healthy middle-aged and older adults … All self-reported AEs were mild in severity. The reported symptoms included nausea, flushing, leg cramps and increased bruising during the NR condition","accessed":"2026-08-27"},{"id":"conze2019","url":"https://europepmc.org/article/PMC/PMC6611812","label":"Safety and metabolism of long-term NIAGEN (nicotinamide riboside chloride) in healthy overweight adults (Conze et al., Sci Rep 2019)","quote":"Consumption of 100, 300 and 1000 mg NR dose-dependently and significantly increased whole blood NAD+ (i.e., 22%, 51% and 142%) … within 2 weeks … There were no reports of flushing and no significant differences in adverse events between the NR and placebo-treated groups … Participants were instructed to take 4 capsules daily after breakfast","accessed":"2026-08-27"},{"id":"dollerup2018","url":"https://europepmc.org/article/MED/29992272","label":"Randomized placebo-controlled trial of nicotinamide riboside in obese men (Dollerup et al., Am J Clin Nutr 2018)","quote":"12 wk of NR supplementation in doses of 2000 mg/d appears safe, but does not improve insulin sensitivity and whole-body glucose metabolism in obese, insulin-resistant men","accessed":"2026-08-27"},{"id":"efsa2019_nr","url":"https://europepmc.org/article/PMC/PMC7009190","label":"EFSA NDA Panel — Safety of nicotinamide riboside chloride as a novel food (EFSA Journal 2019)","quote":"proposed to be used in food supplements for the healthy adult population at levels up to 300 mg/day … the NF is safe under the proposed conditions of use for the healthy adult population, excluding pregnant and lactating women, and that an intake of the NF up to 230 mg/day is safe for pregnant and lactating women … a source from which nicotinamide, a form of niacin, is bioavailable","accessed":"2026-08-27"},{"id":"fda_grn635","url":"https://www.hfpappexternal.fda.gov/scripts/fdcc/index.cfm?id=635&set=GRASNotices","label":"FDA GRAS Notice Inventory — GRN No. 635, nicotinamide riboside chloride (ChromaDex), letter 3 Aug 2016","quote":"Nicotinamide riboside chloride … Source of vitamin B3 in vitamin waters, protein shakes, nutrition bars, gum, chews, and powdered beverages at a maximum level of 0.0057% by weight as consumed … FDA has no questions","accessed":"2026-08-27"},{"id":"fda_nmn_2022","url":"https://downloads.regulations.gov/FDA-2022-S-0023-0051/attachment_2.pdf","label":"FDA letter on NMN new dietary ingredient notification, 4 Nov 2022 (regulations.gov FDA-2022-S-0023-0051)","quote":"NMN is excluded from the dietary supplement definition under 21 U.S.C. § 321(ff)(3)(B)(ii) and may not be marketed as or in a dietary supplement","accessed":"2026-08-27"},{"id":"venable2025","url":"https://www.venable.com/insights/publications/2025/10/fda-declares-nicotinamide-mononucleotide-is","label":"FDA Declares Nicotinamide Mononucleotide Is a Dietary Supplement (Venable LLP client alert, 2 Oct 2025)","quote":"September 29, 2025 … NMN is not excluded from the definition of a dietary supplement … NMN remains classified as a New Dietary Ingredient (NDI), meaning companies must still satisfy premarket notification requirements","accessed":"2026-08-27"},{"id":"zhang2025","url":"https://europepmc.org/article/MED/39116016","label":"Efficacy of oral NMN on glucose and lipid metabolism: systematic review with meta-analysis of RCTs (Zhang, Poon & Wong, Crit Rev Food Sci Nutr 2025)","quote":"12 studies with a total of 513 participants … an overall significant effect of NMN supplementation in elevating blood NAD levels. However, most of the clinically relevant outcomes were not significantly different between NMN supplementation and control group … high risk of bias in the other five studies … an exaggeration of the benefits of NMN supplementation may exist in the field","accessed":"2026-08-27"},{"id":"prokopidis2025","url":"https://europepmc.org/article/PMC/PMC12022230","label":"Effect of NMN and NR on skeletal muscle mass and function: systematic review and meta-analysis (Prokopidis et al., J Cachexia Sarcopenia Muscle 2025)","quote":"Current evidence does not support NMN and NR supplementation for preserving muscle mass and function in adults with mean age of over 60 years","accessed":"2026-08-27"},{"id":"chen2024","url":"https://europepmc.org/article/PMC/PMC11557618","label":"Effects of NMN on glucose and lipid metabolism in adults: systematic review and meta-analysis of RCTs (Chen et al., Curr Diab Rep 2024)","quote":"Eight RCTs on NMN (dosage ranged 250-2000 mg/d for a duration of 14 days to 12 weeks) … no significant benefit of NMN on fasting glucose, fasting insulin, glycated hemoglobin, homeostatic model assessment for insulin resistance and lipid profile … [table] Yoshino et al., 2021 USA 25 prediabetic women 10 weeks NMN (250 mg/d)","accessed":"2026-08-27"},{"id":"yang2026","url":"https://europepmc.org/article/MED/42514320","label":"Safety and metabolism-related outcomes of oral NMN in adults: systematic review and meta-analysis (Yang et al., Nutrients 2026)","quote":"Fifteen trials were included … NMN doses ranged from 250-2000 mg/day, and durations ranged from 14 days to 24 weeks. NMN did not increase overall, serious, withdrawal-related, or system-specific adverse events … Broad metabolic benefits were not evident","accessed":"2026-08-27"},{"id":"hsa_prohibited_2025","url":"https://file.go.gov.sg/hsa-chp-prohibited-restricted-ing-guidelines.pdf","label":"HSA — Guidelines on Prohibited and Restricted Ingredients in Health Supplements and Traditional Medicines, GL-CHPB-1-012 Rev 001 (Oct 2025)","quote":"75. Nicotinamide — Restricted use in HS and TM — Maximum Daily Dose: When for oral use by general adult population, the maximum recommended daily dose should not provide more than 450mg [nmn, nicotinamide riboside not listed in Annex A or B]","accessed":"2026-08-27"},{"id":"holisticway_sg_nmn","url":"https://www.holisticway.com.sg/search?q=NMN","label":"Holistic Way Singapore — site search 'NMN' (SGD pricing, 2 Bukit Batok Street 24, Singapore 659480)","quote":"Bio-NMN 400mg … Bio-NMN Men 400mg … Bio-NMN Women 400mg","accessed":"2026-08-27"}],"brand_certs":null,"updated_at":"2026-08-29T16:16:26.600885+08:00"},"disclaimer":"kozen-x is not a medical device and does not give medical advice. it lists what published sources have written down. absence of a record is not the same as safe."}