What Is NAD+?
By the Zen Well Labs Research Team · Last reviewed September 2026 · For laboratory research reference only
Short answer: NAD+ (β-nicotinamide adenine dinucleotide, oxidized form; INN name nadide) is a coenzyme found in all living cells. It is not a peptide. It is a dinucleotide: two nucleotides, adenosine monophosphate and nicotinamide mononucleotide, joined through a pyrophosphate bridge. PubChem lists it under CID 5892 with molecular formula C21H27N7O14P2, molecular weight ≈663.4 g/mol and CAS number 53-84-9. In biochemistry NAD+ is best known as an electron carrier: it accepts a hydride to become NADH. It is also the substrate of NAD+-consuming enzymes such as sirtuins, PARPs and CD38. Published work on these topics is largely enzymology, cell-culture and animal-model research. Zen Well Labs sells NAD+ (500 mg and 1000 mg) as a laboratory reagent for in-vitro research only. It is not a drug or a dietary supplement, and it is not for human or veterinary use.
NAD+ at a glance
| Common names | NAD+, NAD, β-NAD, β-NAD+, nadide, diphosphopyridine nucleotide (DPN, historical), coenzyme I (historical) |
|---|---|
| Compound class | Dinucleotide coenzyme (pyridine nucleotide), **not a peptide** |
| Molecular formula | C21H27N7O14P2 (PubChem representation, free acid) |
| Molecular weight | ≈663.4 g/mol (free acid; salt forms and hydrates are heavier) |
| Monoisotopic mass | ≈663.109 Da |
| CAS number | 53-84-9 |
| PubChem CID | 5892 |
| FDA UNII | 0U46U6E8UK |
| Reduced counterpart | NADH: C21H29N7O14P2, ≈665.4 g/mol (PubChem CID 439153) |
| Typical supplied form | Dry, hygroscopic solid (powder), often lyophilized |
| Regulatory status | Zen Well Labs NAD+ is a research reagent; not an FDA-approved drug; not for human or veterinary use |
NAD+ is a coenzyme, not a peptide
Zen Well Labs lists NAD+ next to research peptides, but it belongs to a different chemical class. Peptides are chains of amino acids joined by amide bonds. NAD+ has no amino acids. Its parts are:
- a nicotinamide ring (the redox-active part), attached through a β-N-glycosidic bond to ribose;
- an adenine base, attached to a second ribose;
- two phosphate groups joining the two ribose-5′-phosphates as a pyrophosphate (diphosphate) linkage.
This matters in the lab. Peptide rules of thumb about proteolysis, sequence errors and residue-specific oxidation do not apply. The relevant chemistry is hydrolysis of the glycosidic and pyrophosphate bonds, pH sensitivity and hygroscopicity. Analytical identity is confirmed by UV absorbance ratios, HPLC and mass spectrometry, not by peptide sequencing.
Where does NAD+ come from?
NAD+ was first identified in the early twentieth century as a heat-stable “cozymase” fraction needed for yeast fermentation, work associated with Arthur Harden and William Young. Its structure and role as a hydrogen (hydride) carrier were worked out over the following decades.
Cells make NAD+ through three main routes, reviewed in detail by Cantó, Menzies and Auwerx (Cell Metabolism, 2015) and Covarrubias et al. (Nature Reviews Molecular Cell Biology, 2021):
- De novo synthesis from tryptophan through the kynurenine pathway.
- The Preiss–Handler pathway from nicotinic acid.
- The salvage pathway, which recycles nicotinamide released by NAD+-consuming enzymes. NAMPT (nicotinamide phosphoribosyltransferase) converts nicotinamide to nicotinamide mononucleotide (NMN), and NMNAT enzymes convert NMN to NAD+. Nicotinamide riboside enters through NRK kinases.
Research-grade NAD+ is manufactured commercially, typically by enzymatic or fermentation-based processes followed by purification. The source process for any given lot should be read from the supplier documentation, not assumed.
Redox biochemistry: NAD+ and NADH
NAD+ is the oxidized form of the couple. In dehydrogenase reactions it accepts a hydride ion (two electrons and one proton) at the C4 position of the nicotinamide ring, forming NADH and releasing a proton:
NAD+ + 2e⁻ + H⁺ ⇌ NADH
The standard biochemical reduction potential of the NAD+/NADH couple is about −0.32 V. That places it in the middle of catabolic pathways, where glycolysis and the citric acid cycle reduce NAD+, and mitochondrial complex I reoxidises NADH while pumping protons. The cellular NAD+/NADH ratio acts as a readout of redox state and is a common endpoint in metabolic cell-culture studies.
NAD+ can also be phosphorylated by NAD kinase to NADP+, whose reduced form NADPH supplies reducing power for biosynthesis and antioxidant systems. NADP+ is a different compound with an extra phosphate. Do not confuse it with NAD+ when reading a label or COA.
The redox change also gives a convenient spectroscopic handle. Both forms absorb near 260 nm (adenine), but only NADH has a strong band at 340 nm (molar absorptivity ≈6,220 M⁻¹ cm⁻¹). That is why so many dehydrogenase assays follow the appearance or disappearance of absorbance at 340 nm.
What has the published research looked at?
NAD+ has a very large literature. Themes that appear repeatedly in cell-culture and animal-model research include:
- NAD+-consuming signalling enzymes. Besides redox chemistry, NAD+ is used up as a substrate by sirtuins (NAD+-dependent deacylases), poly(ADP-ribose) polymerases (PARPs, involved in the DNA-damage response) and the NAD+ glycohydrolase/cyclase CD38. These enzymes cleave NAD+ and release nicotinamide, which links NAD+ levels to protein acylation, DNA-repair signalling and calcium-signalling messengers. Cantó et al. (2015) review how these pathways connect mitochondrial and nuclear metabolism.
- Tissue NAD+ levels in rodent models. Published mouse studies have measured tissue NAD+ content at different ages and the contribution of NAD+-consuming enzymes such as CD38 (Camacho-Pereira et al., Cell Metabolism, 2016). Verdin (Science, 2015) and Covarrubias et al. (2021) review this preclinical literature.
- Enzymology and assay reagent use. Most commonly, NAD+ is a routine cofactor in in-vitro enzyme assays, including lactate, alcohol and glucose-6-phosphate dehydrogenase systems, coupled assays and metabolomics standards. This reagent use is the most direct laboratory application of research-grade NAD+.
These are mechanistic and preclinical research themes. They do not show that NAD+ from any supplier has a health effect in people.
What is missing / regulatory status
- Not an approved drug product. Zen Well Labs NAD+ is not an FDA-approved drug and is not manufactured, labelled or intended as one.
- Not a dietary supplement, food or cosmetic. Consumer NAD-related products sold elsewhere are a separate regulatory category. Zen Well Labs NAD+ is a laboratory reagent and is not sold for ingestion or any other human use.
- Preclinical findings do not transfer automatically. Cell and rodent results on NAD+ metabolism depend on the model, tissue, measurement method and NAD+ precursor studied. Precursors such as NMN or nicotinamide riboside are different molecules from NAD+ itself, and findings for one should not be attributed to another.
- Measurement is difficult. NAD+ and NADH interconvert and degrade during sample handling. Published tissue values vary with extraction chemistry, which is one reason careful controls matter when comparing studies.
Storage and stability in the laboratory
NAD+ is not a peptide, but the same cold, dry, dark and sealed storage habits apply to the supplied solid:
- Temperature: store sealed at −20 °C, the storage temperature commonly listed by reagent manufacturers for NAD+.
- Dry: NAD+ is hygroscopic and should be kept desiccated. Let a cold container reach room temperature before opening to limit condensation, and reseal promptly.
- Dark: keep the container protected from light, for example in an amber vial or the original outer packaging. Light protection is standard good practice for pyridine nucleotides. Photosensitivity is better documented for the reduced form, NADH, than for NAD+.
- Sealed: keep the container closed between uses, and record the batch number and date of first opening.
See our guide to lyophilized peptide storage and stability for the general principles of cold, dry, light-protected storage.
How are NAD+ identity and purity verified?
Peptide COAs lean on HPLC plus MS. NAD+ COAs typically combine:
- HPLC purity (percent peak area), which separates NAD+ from breakdown products such as nicotinamide and ADP-ribose and from related nucleotides.
- UV spectral ratios. Manufacturer specifications for NAD+ commonly include A250/A260 (about 0.8) and A280/A260 (about 0.2) ratios. An enzymatic check, reduction to NADH with a dehydrogenase followed by measurement at 340 nm, confirms that the material is functionally active.
- Mass spectrometry consistent with ≈663.1 Da (monoisotopic, free acid). A result about 2 Da higher suggests NADH. A result about 80 Da higher suggests NADP+.
- Form and water content. The COA should say whether the material is the free acid or a salt (for example sodium) and should report water content, because both change the effective NAD+ content per milligram.
Our explainer on how to read a peptide COA covers the general fields (batch number, method, purity, identity). The same reading habits apply to NAD+ documentation.
Frequently asked questions
Is NAD+ a peptide?
No. NAD+ is a dinucleotide coenzyme made of nicotinamide, adenine, two ribose sugars and two phosphates. It contains no amino acids.
What is the molecular weight and CAS number of NAD+?
About 663.4 g/mol for the free acid (formula C21H27N7O14P2), CAS 53-84-9, PubChem CID 5892. Salt forms and hydrates have higher formula weights.
What is the difference between NAD+ and NADH?
NAD+ is the oxidized form. NADH is the reduced form, carrying an extra hydride on the nicotinamide ring (C21H29N7O14P2, ≈665.4 g/mol). Only NADH absorbs strongly at 340 nm.
How should NAD+ be stored in the lab?
Keep the supplied solid sealed, desiccated, protected from light and at −20 °C.
Is NAD+ from Zen Well Labs a dietary supplement?
No. It is a laboratory reagent for in-vitro research. It is not a drug, food, cosmetic or dietary supplement, and it is not for human or veterinary use.
What are Zen Well Labs NAD+ 500 mg and 1000 mg products intended for?
In-vitro laboratory research only, such as enzymology, assay development and cell-culture work under your institution’s protocols.
References
- Cantó C, Menzies KJ, Auwerx J. NAD+ metabolism and the control of energy homeostasis: a balancing act between mitochondria and the nucleus. Cell Metabolism. 2015;22(1):31–53.
- Covarrubias AJ, Perrone R, Grozio A, Verdin E. NAD+ metabolism and its roles in cellular processes during ageing. Nature Reviews Molecular Cell Biology. 2021;22(2):119–141.
- Verdin E. NAD+ in aging, metabolism, and neurodegeneration. Science. 2015;350(6265):1208–1213.
- Camacho-Pereira J, Tarragó MG, Chini CCS, Nin V, et al. CD38 dictates age-related NAD decline and mitochondrial dysfunction through an SIRT3-dependent mechanism. Cell Metabolism. 2016;23(6):1127–1139.
- Merck/Sigma-Aldrich (Calbiochem). NAD+, Free Acid, product 481911: product information (storage conditions, hygroscopicity, spectral ratios).
- PubChem Compound Summary, CID 5892 (Nadide; NAD+). National Center for Biotechnology Information.
- PubChem Compound Summary, CID 439153 (NADH). National Center for Biotechnology Information.
Related
Research use only. All products sold by Zen Well Labs are intended strictly for in-vitro laboratory research. They are not drugs, foods, cosmetics or dietary supplements, are not approved by the FDA for any use, and are not for human or veterinary use. Nothing on this page is medical advice, and nothing here describes or recommends administration to humans or animals.
