Is NAD+ a peptide?

No, NAD+ is not a peptide. A peptide is a short chain of amino acids, and NAD+ contains no amino acids at all: it is a coenzyme made of two nucleotides, joined to each other through their phosphate groups.

People search for "NAD peptide" and "is NAD a peptide" because NAD+ is sold by many of the clinics and websites that sell peptides, usually in the same kind of small injectable vial. The chemistry also has a practical side, because it decides how a batch of NAD+ should be tested and how it should be stored.

What is a peptide?

A peptide is a short chain of amino acids, typically between 2 and 50, held together by peptide bonds. A chain of 51 or more is a polypeptide, and proteins are made from one or more polypeptides, according to the US National Human Genome Research Institute's glossary. Each peptide bond forms when the carboxyl group of one amino acid reacts with the amino group of the next, releasing a molecule of water (StatPearls, Protein Structure and Function). The order of the amino acids along the chain is called the sequence, or primary structure (StatPearls, Proteins Enzymes).

Glutathione, which often sits on the same wellness menus as NAD+, is a real peptide. It is a tripeptide of glutamic acid, cysteine and glycine, with a molecular weight of 307.33 g/mol (PubChem). Insulin, at 51 amino acids in two chains, sits just past that 50 mark, and the same StatPearls chapter still describes it as a peptide hormone.

What is NAD+ made of?

NAD+ is two mononucleotides joined together: adenosine monophosphate (AMP) and nicotinamide mononucleotide (NMN), as a 2012 overview in Circulation Research describes it. A nucleotide is a sugar attached to a phosphate group and a nitrogen-containing base, and nucleotides are best known as the units DNA and RNA are made from (genome.gov). The base in AMP is adenine, one of the four bases in DNA. The base in NMN is nicotinamide, which with nicotinic acid makes up what is called niacin, or vitamin B3.

The two halves are held together by a pyrophosphate bond, a link between their phosphate groups. Some enzymes on the outer surface of cells cut that bond, splitting NAD+ back into AMP and NMN (Gasparrini and colleagues, 2021). NMN, which is sold as a supplement in its own right, is therefore one half of the NAD+ molecule. We compare the two in NMN vs NAD+.

Put together, NAD+ has the formula C₂₁H₂₇N₇O₁₄P₂, a molecular weight of 663.4 g/mol and the CAS number 53-84-9 (PubChem). The P₂ in that formula is the two phosphorus atoms of the phosphate groups, and glutathione's formula, C₁₀H₁₇N₃O₆S, has no phosphorus in it at all. NAD+ also weighs more than twice as much as glutathione, so size is no guide to whether a molecule is a peptide.

NAD+ and peptides side by side

Why is NAD+ sold alongside peptides?

Mostly because of where it is sold and how it is packaged. Clinics and online shops that offer peptide injections often list NAD+ on the same page, and it tends to arrive the way many peptides do, as a small vial for injection. Over time "peptide" has come to cover the whole shelf, which is where searches such as "NAD+ peptide" and "what is NAD peptide" come from.

People also blur the two for a biochemical reason: NAD+ does its work alongside proteins. It is a coenzyme for redox reactions and a cofactor or substrate for hundreds of enzymes, including the sirtuins, the PARPs and CD38, according to a 2021 review in Nature Reviews Molecular Cell Biology. Enzymes are proteins, made of amino acids linked into one or more polypeptide chains, and some are inactive until a cofactor, either a metal ion or an organic compound, attaches to them (StatPearls, Proteins Enzymes). NAD+ is one of those organic cofactors.

The distinction goes back to the molecule's discovery. Studying fermentation in yeast, Arthur Harden found a large enzyme and a separate, much smaller "co-ferment". Hans von Euler-Chelpin later isolated that coenzyme, NAD+, and showed it was made of two mononucleotides, AMP and NMN. The two men won the 1929 Nobel Prize for their work on sugar fermentation and its enzymes (Nakamura and colleagues, 2012).

What the difference means if you are buying NAD+

A peptide is identified by its mass and its amino acid sequence. In the US Pharmacopeia's quality tests for synthetic peptide medicines, mass spectrometry checks both, and HPLC measures purity (McCarthy and colleagues, 2023). NAD+ has no sequence to read. It is one compound with one formula, so the questions about a batch are simpler: is it NAD+, and how much of the material is NAD+ rather than something related to it?

HPLC, short for high-performance liquid chromatography, answers the second question for both kinds of molecule by separating the compounds in a sample so each can be measured. In one published laboratory method, NAD+ comes through as a sharp peak that separates completely from other NAD+-related compounds, and the area of that peak, read against a standard, gives the amount. Our NAD+ is ≥99% pure by HPLC. Every batch is measured by an independent laboratory, and the certificate in the box is that batch's own result. The figures are also on our science page.

Storage needs more thought with NAD+ in solution, because it breaks down slowly in water and the conditions change how fast. A 2024 study in Molecules kept NAD+ and its reduced form, NADH, in three common laboratory buffers for 43 days. NAD+ broke down almost entirely in one buffer and lost about 4% in another. The authors note that NAD+ degrades faster in alkaline conditions, and in their most stable buffer a rise from 19°C to 25°C nearly tripled the rate at which NADH broke down. Those were laboratory solutions, so the numbers do not carry over to any product, but they show why an NAD+ solution is kept cold.

Ours is a pre-mixed solution in a sealed vial. It ships cold, packed to hold temperature, and we treat it as perishable. If a parcel arrives warm, tell us before you use it.

The kit is a 1000mg vial with a reusable metal auto-injector, single-use needles and wipes. It is made in the UK and sold as a food supplement, legal for human intake, and it is not a licensed medicine. Speak to a doctor before using it if you are pregnant, breastfeeding, taking prescribed medication or under medical supervision, and do not use it if you are under 18. The details are on the NAD+ kit page.

What do "NAD+ peptide benefits" searches mean?

Someone typing "NAD+ peptide benefits" or "NAD+ peptide what does it do" wants to know what NAD+ does, and calling it a peptide does not change the answer. In cells, NAD+ is a coenzyme for the redox reactions of energy metabolism. It is also consumed by other enzymes, among them the sirtuins and the PARPs, and three of the PARPs have a central role in repairing damaged DNA (Covarrubias and colleagues, 2021).

The evidence on ageing is less tidy than it is often made to sound. The same review describes a gradual decline in tissue and cellular NAD+ with age in several species, including rodents and humans. A 2026 study in Nature Metabolism measured NAD+ in whole blood across seven human cohorts and found that levels stayed stable with age and across lifestyle interventions. The review's authors also say that much remains to be learnt, including whether restoring NAD+ is safe and whether it benefits people as they age.

We go through what human trials have and have not found, side effects included, in NAD+ benefits and side effects.