NAD+ (Nicotinamide Adenine Dinucleotide): Is NAD a Peptide?

Overview

A peptide is a chain of amino acids linked by peptide bonds. NAD+ is built differently. One of its nucleotides carries the base adenine and the other carries nicotinamide, a form of vitamin B3. Each base sits on a ribose sugar, and the two halves are bridged by a pair of phosphate groups. PubChem records the neutral form as C21H27N7O14P2, with a molecular weight of 663.4 g/mol, and CAS number 53-84-9.

The compound has collected several names. Its international non-proprietary name is nadide, and older papers call it coenzyme I, DPN (diphosphopyridine nucleotide) or cozymase. The "+" marks the positively charged nitrogen in the nicotinamide ring of the oxidised form. It is not a brand mark or a stronger grade. In everyday writing, NAD, NAD+ and "NAD plus" usually mean the same compound. Strictly, "NAD" covers both the oxidised (NAD+) and reduced (NADH) forms.

NAD+ appears in peptide catalogues for commercial rather than chemical reasons: research suppliers list it alongside peptides, often in the same vial and prefilled-pen formats, which probably explains the name "NAD peptide". This guide covers the chemistry, how the NAD+ 1000mg Double Pen is labelled and tested, storage, and UK and anti-doping status. It does not discuss effects in people.

The NAD+ 1000mg Double Pen is one pack of two prefilled pens labelled KLIKNAD+, each labelled 500mg of NAD+; the 1000mg total is for the pack, not the content of one pen. This shop sells these pens, so links to them from this page are commercial. Apart from one laboratory report on a single sample, described below, none of the sources cited here tested this product.

The MHRA's products database, which indexes the active substances in UK medicines, lists nicotinamide and nicotinic acid but no medicine with NAD+ or nadide as an active substance (checked 22 October 2026). These pens are not licensed medicines. Being unlicensed does not take a product outside medicines law: the MHRA decides whether a product is a medicine by what it does and how it is presented, including its labelling, packaging, websites, promotional material and customer reviews.

Discovery & Background

NAD+ was one of the first coenzymes to be recognised. The 1929 Nobel Prize in Chemistry, shared by Arthur Harden and Hans von Euler-Chelpin, honoured work on the fermentation of sugar. Harden had found that yeast juice passed through a fine filter split into two fractions. Neither could ferment sugar alone, but they could once mixed again. The small, filterable partner became known as co-zymase. Von Euler-Chelpin's group then concentrated co-zymase and concluded that it was very probably a pentose nucleoside, a base attached to a five-carbon sugar.

Mechanism of Action

In cell biology NAD+ has two textbook roles. It is a redox coenzyme that carries electrons between reactions, and it is a substrate that certain enzymes split. The points below describe laboratory biochemistry, not the effects of any product.

• 1
  Electron carrier: dehydrogenase enzymes take two electrons and a proton (together, a hydride ion) from a substrate and place them on the nicotinamide ring of NAD+, giving NADH. Other enzymes take them back, so NADH returns to NAD+. The two are one coenzyme in two states, not separate compounds.
• 2
  NAD+ and NADH side by side: PubChem lists NADH as C21H29N7O14P2 (665.4 g/mol) and the NAD+ ion as C21H28N7O14P2+ (664.4 g/mol), so the reduced form carries exactly one more hydrogen, the one added as a hydride. The neutral NAD+ record given above (C21H27N7O14P2, 663.4 g/mol) shows one hydrogen fewer again, because it is drawn with one phosphate group ionised to balance the positive charge.
• 3
  Where it works: in glycolysis, and in the reactions inside mitochondria that break down fuel molecules, NAD+ accepts electrons and becomes NADH. NADH passes the electrons to the mitochondrial respiratory chain, which turns it back into NAD+.
• 4
  A close relative: NADP+ is NAD+ with an extra phosphate on the 2′ position of the adenosine ribose, added by the enzyme NAD+ kinase. Its reduced form is NADPH.
• 5
  Substrate for other enzymes: PARP enzymes transfer its ADP-ribose part to proteins, and sirtuins use it to remove acyl groups such as acetyl from proteins. Both reactions split NAD+ and release nicotinamide, which cells can convert back into NAD+.
• 6
  Precursors, as chemistry: nicotinic acid (niacin) and nicotinamide are the classic forms of vitamin B3. Nicotinamide riboside (NR) is nicotinamide joined to a ribose sugar, and nicotinamide mononucleotide (NMN) is NR carrying one phosphate group. Cells build NAD+ from each of these, and from the amino acid tryptophan, by separate routes; each route includes a step that adds an AMP (adenylyl) group.
• 7
  What this does not show: these points describe cell biochemistry in general. They are not evidence about any product, and none of the research behind them tested a product sold here.

Frequently Asked Questions