Scientifically reviewed by Dr Stephan Hansberg
NAD+ vs NMN vs NADH: structure, research and legal status
How NAD+, NMN and NADH differ in structure and role in the NAD+ metabolome, how oral and injectable forms appear in research, and where NMN stands with the US FDA and EU novel food rules in 2026.
Key takeaways
- •NAD+ is the oxidised coenzyme, NADH is its reduced form, and NMN is a precursor that cells convert into NAD+.
- •NMN is one half of the NAD+ molecule: NAD+ is formed when NMN is joined to AMP by NMNAT enzymes.
- •Research has studied NMN mainly by mouth in animals and small human trials, and NAD+ itself by intravenous infusion in small pilot studies.
- •In the US, the FDA said in November 2022 that NMN was excluded from dietary supplements, then reversed that position on 29 September 2025.
- •In the EU, NMN is a novel food; EFSA issued a positive safety opinion on one NMN ingredient in May 2026, but we found no completed EU authorisation as of October 2026.
The short answer
NAD+, NMN and NADH are three members of the same metabolic family. NAD+ is the oxidised coenzyme that cells use in hundreds of reactions, NADH is the reduced form that NAD+ becomes when it accepts electrons, and NMN (nicotinamide mononucleotide) is a precursor that cells convert into NAD+. They differ in size, in role, and in how regulators treat them when sold to consumers.
Structures side by side
NMN is literally one half of NAD+. Join NMN to adenosine monophosphate through a phosphate bridge and the result is NAD+. Add two electrons and a proton to the nicotinamide ring of NAD+ and the result is NADH.
| Property | NAD+ | NADH | NMN |
|---|---|---|---|
| Full name | Nicotinamide adenine dinucleotide (oxidised) | Nicotinamide adenine dinucleotide (reduced) | Nicotinamide mononucleotide |
| Class | Dinucleotide coenzyme | Dinucleotide coenzyme | Mononucleotide |
| Formula | C21H27N7O14P2 | C21H29N7O14P2 | C11H15N2O8P |
| Molar mass | 663.4 g/mol | 665.4 g/mol | 334.2 g/mol |
| Role | Electron acceptor; substrate for sirtuins, PARPs, CD38 | Electron donor to the respiratory chain | Precursor converted to NAD+ |
| Peptide? | No | No | No |
Roles in the NAD+ metabolome
Cells keep NAD+ levels up mainly through the salvage pathway. Enzymes that consume NAD+, such as sirtuins, PARPs and CD38, release nicotinamide. The enzyme NAMPT converts nicotinamide into NMN, and NMNAT enzymes then join NMN to AMP to rebuild NAD+. Other precursors, such as nicotinamide riboside and nicotinic acid, enter the same network by different routes.
NADH is not a precursor in this sense. It is the electron-carrying form of the same molecule, produced in glycolysis and the citric acid cycle and reoxidised to NAD+ when it passes electrons to complex I of the mitochondrial respiratory chain. The ratio of NAD+ to NADH is itself a measure of a cell's redox state.
Reviews of NAD+ biology describe a decline in tissue NAD+ levels with age in animal models and human tissues, which is why precursors such as NMN have attracted research interest.
Oral and injectable forms in research
NMN has mostly been studied by mouth. A widely cited 2016 study in Cell Metabolism gave NMN to mice in drinking water over twelve months and measured age-associated physiological markers. In 2021 a randomised, placebo-controlled trial published in Science examined NMN and muscle insulin sensitivity in postmenopausal women with prediabetes. Human trials so far are small and short, and reviews caution that much of the evidence remains preclinical.
NAD+ itself is a larger, charged molecule, and research on it in people has largely used intravenous infusion. A 2019 pilot study measured how plasma and urine NAD+ metabolites changed during and after an intravenous NAD+ infusion in a small group of healthy men. Oral NADH has also been sold in supplements, but published research on it is limited.
These are descriptions of study designs, not of results in people, and none of them amounts to an approved medical use.
Regulatory status of NMN: United States
In a letter dated 4 November 2022, the FDA concluded that beta-NMN was excluded from the definition of a dietary supplement under the drug-exclusion clause of the Federal Food, Drug, and Cosmetic Act, because it had been authorised for investigation as a new drug (Metro International Biotech's MIB-626) before, in the agency's view, it was marketed as a supplement. Trade groups, including the Natural Products Association and the Alliance for Natural Health USA, petitioned the FDA, and the Natural Products Association sued.
On 29 September 2025 the FDA reversed its position. Responding to the citizen petitions, it concluded that there was sufficient evidence NMN had been marketed as a dietary supplement in the US before the drug authorisation date, so NMN is not excluded. NMN remains a new dietary ingredient, so companies still have to meet the premarket notification requirements.
Regulatory status of NMN: European Union
In the EU, NMN is treated as a novel food under Regulation (EU) 2015/2283, which means it cannot lawfully be sold as a food or food supplement until it is authorised and added to the Union list. Several applications have been filed. In May 2026 EFSA published a positive safety opinion on one chemically synthesised beta-NMN ingredient (applicant EffePharm) for use in food supplements for adults.
An EFSA opinion is a scientific step, not an authorisation. The European Commission and Member States must still adopt an implementing regulation. As of October 2026 we found no published authorisation, so check the Union list of novel foods before relying on any EU status. This is general information, not legal advice.
Where Celyfe fits
Celyfe does not sell NMN or NADH. It supplies NAD+ itself, in the NAD+ Precision Pen: 500mg in a pre-filled 3ml cartridge (166.7mg per ml), for laboratory and research use. The certificate for batch A26085 (Analiza Bialek, Wroclaw, HPLC, dated 2 October 2026) reports 99% purity and is in the COA library at /coa. The pen ships cold-chain and tracked and is stored at 2 to 8 °C (do not freeze). See /products/nad-precision-pen.
Sources
- PubChem (National Library of Medicine). NAD+ CID 5892; NADH CID 439153; nicotinamide mononucleotide CID 14180 (formulas and molar masses).
- Covarrubias AJ, Perrone R, Grozio A, Verdin E. NAD+ metabolism and its roles in cellular processes during ageing. Nature Reviews Molecular Cell Biology, February 2021. PMID 33353981.
- Rajman L, Chwalek K, Sinclair DA. Therapeutic Potential of NAD-Boosting Molecules: The In Vivo Evidence. Cell Metabolism, March 2018. PMID 29514064.
- Mills KF, Yoshida S, Stein LR et al. Long-Term Administration of Nicotinamide Mononucleotide Mitigates Age-Associated Physiological Decline in Mice. Cell Metabolism, December 2016. PMID 28068222.
- Yoshino M, Yoshino J, Kayser BD et al. Nicotinamide mononucleotide increases muscle insulin sensitivity in prediabetic women. Science, June 2021. PMID 33888596.
- Grant R, Berg J, Mestayer R et al. A Pilot Study Investigating Changes in the Human Plasma and Urine NAD+ Metabolome During a 6 Hour Intravenous Infusion of NAD. Frontiers in Aging Neuroscience, September 2019. PMID 31572171.
- SupplySide Supplement Journal. FDA says ingredient studied as drug, beta-NMN, is excluded from supplements. November 2022 (FDA letter of 4 November 2022).
- Venable LLP. FDA Declares Nicotinamide Mononucleotide Is a Dietary Supplement. 2 October 2025 (FDA letters of 29 September 2025).
- National Law Review. FDA Determines NMN Lawful in Dietary Supplements. 2025.
- NutraIngredients. EFSA issues positive safety opinion on EffePharm's NMN. 13 May 2026.
- Regulation (EU) 2015/2283 of the European Parliament and of the Council on novel foods.
Research use only
Celyfe supplies research peptides for laboratory and research use only. Nothing on this page is guidance on use in humans or animals.
The regulatory summary above is general information as of October 2026 and is not legal advice.
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