NAD+ Research Guide: Structure, NAD+ vs. NADH, COA and Handling
NAD+ (nicotinamide adenine dinucleotide) is a coenzyme found in every living cell. It is not a peptide. Labs use it as a redox cofactor in enzyme assays and as the substrate in sirtuin, PARP and CD38 research. This page covers its structure, how it differs from NADH and its precursors, how to read an NAD+ certificate of analysis, and handling, using FRO Peptides’ own lot report as the example.
NAD+ at a glance
| Full name | Nicotinamide adenine dinucleotide, oxidized form (β-NAD+) |
|---|---|
| Compound class | Dinucleotide coenzyme (not a peptide) |
| Molecular formula | C21H27N7O14P2 |
| Molecular weight | ≈ 663.43 g/mol |
| CAS number | 53-84-9 |
| UV absorbance | Maximum near 260 nm (adenine) |
| Supplied as | Lyophilized powder in sealed vials |
| FRO vial sizes | 100mg, 500mg, 1,000mg |
| FRO tested purity | 99.68% by HPLC (500mg, sample 566M-HS3A) |
Structure: two nucleotides and a phosphate bridge
NAD+ is built from two nucleotides joined through their phosphate groups. One half is adenosine monophosphate (adenine, ribose, phosphate). The other half is nicotinamide mononucleotide (nicotinamide, ribose, phosphate). The two phosphates link into a pyrophosphate bridge, which gives the molecule its “dinucleotide” name.
The working part is the nicotinamide ring. In NAD+ it carries a positive charge and can accept a hydride (two electrons and a proton), which turns it into NADH. That reversible switch is why NAD+ shows up in so many dehydrogenase reactions. The molecule is highly polar and very water-soluble.
Why labs study it
- Enzyme assays. NAD+ is the electron acceptor for dehydrogenases in glycolysis, the TCA cycle and many other pathways. NADH absorbs at 340 nm and NAD+ does not, so many standard assays follow a reaction by watching absorbance at 340 nm rise or fall.
- Sirtuin research. Sirtuins are deacylase enzymes that consume NAD+ as a substrate and release nicotinamide. In vitro sirtuin activity assays need a defined NAD+ supply.
- PARP and ADP-ribosylation. PARP enzymes use NAD+ to attach ADP-ribose to proteins, a step studied in DNA-damage-response models.
- CD38 and NAD+ turnover. CD38 and related enzymes break NAD+ down, and cell and animal studies track how NAD+ pools shift across metabolic-stress models.
NAD+ vs. NADH vs. NMN and NR
NADH is the reduced form of the same molecule. It carries two more hydrogens (C21H29N7O14P2, about 665.44 g/mol, CAS 58-68-4) and has a second absorbance peak at 340 nm. The two behave differently in solution: NAD+ holds up better in mildly acidic conditions and breaks down in alkaline ones, while NADH is the reverse.
NMN and NR are precursors, not NAD+. Nicotinamide mononucleotide (NMN) is one half of the NAD+ molecule, and nicotinamide riboside (NR) is NMN without its phosphate. Cells convert both into NAD+ through the salvage pathway. They are smaller molecules with different CAS numbers. FRO Peptides sells NAD+ itself. If your protocol calls for NADH, NMN or NR, check the identity line of the COA, because an “NAD+” report doesn’t cover them.
How to read an NAD+ certificate of analysis
A COA is only useful if you know what each line proves. Here is FRO’s 500mg report (AccuMark Labs, sample code 566M-HS3A, lot code 6200, received 05/04/2026, published 09/07/2026) line by line:
| Test | Result | What it tells you |
|---|---|---|
| Identity | NAD+, conforms | The main compound in the vial matches NAD+. |
| HPLC purity | 99.68% (spec > 98.0%) | Share of the sample that is NAD+, measured by UV detection at 220 nm. The chromatogram shows one sharp main peak at about 1.32 minutes, with one small peak just ahead of it. A polar molecule like NAD+ comes off a reversed-phase column early, so an early peak is expected. |
| Quantity | 508.97 mg measured in a 500.0 mg sample | How much compound is actually in the vial, here about 2% over the label. Many COAs skip this line, but it is the one that catches underfilled vials. |
The full report, chromatogram included, is free to open in the NAD+ COA library. Match the code on your vial to the report.
What this report doesn’t cover
This report covers identity, HPLC purity and measured quantity for the 500mg size. It does not include endotoxin, sterility, water content or mass spectrometry results. Two notes specific to NAD+. The detector read at 220 nm, the usual peptide wavelength; NAD+ absorbs most strongly near 260 nm, so a 260 nm run is a common second check. And the report’s “matrix type” field reads “peptide,” which is the lab’s form category, not a description of the molecule. FRO has additional third-party testing underway at Vanguard Laboratory, an ISO 17025 lab, and new results are added to the COA library as they come in.
Red flags on any supplier’s NAD+ COA
- An identity line that says NADH, NMN or NR on a product sold as NAD+, or the reverse.
- No lot or sample code, or a code that doesn’t match the vial.
- Purity with no chromatogram, or no lab name you can look up.
- No measured quantity, only the label claim.
- The same report reused across several products or years.
Storage and handling for research use
- Powder: store frozen (−20 °C), sealed, dry and protected from light. NAD+ is hygroscopic, so let the vial reach room temperature before opening to keep moisture out.
- Solutions: NAD+ dissolves readily in water or a neutral-to-slightly-acidic buffer. Avoid alkaline buffers, where it breaks down faster into nicotinamide and ADP-ribose. Prepare solutions fresh where you can.
- Short-term storage: keep solutions at 2–8 °C, protected from light, within your protocol’s defined window.
- Avoid repeated freeze-thaw. If you need to store solutions frozen, split them into single-use aliquots first.
Frequently asked questions
Is NAD+ a peptide?
No. NAD+ is a dinucleotide coenzyme made of two nucleotides, with no amino acids. That is why FRO lists it as a research compound rather than a research peptide.
Does FRO Peptides publish a COA for NAD+?
Yes. The 500mg report from AccuMark Labs, an independent lab, is published in the COA library, chromatogram included.
What purity is FRO’s NAD+?
The current 500mg lot tested at 99.68% by HPLC, against a specification of more than 98.0%, with 508.97 mg measured.
What is the difference between the 100mg, 500mg and 1,000mg vials?
Only the quantity. All three contain the same compound. The published report covers the 500mg size.
Is NAD+ from FRO for human use?
No. FRO sells NAD+ strictly for laboratory and analytical research. It is not for human or veterinary use.
View NAD+ research compound (100mg–1,000mg) →
Lot report published in the COA library. Ships next business day, FedEx 2-Day.
For laboratory research use only. Not for human or veterinary use. Not a drug, food, or cosmetic under FDA regulations. Nothing on this page is medical advice.