NAD+ has one of the best stories in biochemistry.
It was found in 1906 by two researchers trying to work out why fermentation slowed down. Something in yeast juice kept it going, and boiling did not destroy it. Over the following decades that something turned out to be central to how every living cell on Earth extracts energy from food. It has sat at the heart of more than one Nobel Prize.
Then, roughly a century later, the story opened up again.
Structure and identity
Nicotinamide adenine dinucleotide. CAS 53-84-9, formula C21H27N7O14P2, molecular weight 663.43 Da. Two nucleotides joined through their phosphates, one carrying adenine and one carrying nicotinamide.
It is the odd one out in this catalogue, since everything else here is a peptide. No amino acid sequence on the certificate, and a different set of tests: content assay, water content by Karl Fischer, pH in solution and sodium content, alongside the usual HPLC purity and mass confirmation.
The first job: the electron shuttle
NAD+ picks up electrons, becomes NADH, hands them off, and goes back round. That cycle sits underneath cellular respiration, which is to say underneath the process keeping you alive right now. Your body turns over its entire NAD+ pool many times a day. This part has been textbook for decades and it is still remarkable.
The second job, and why the field reopened
Here is the turn. A group of enzymes discovered much later, the sirtuins, PARPs and CD38, do not borrow NAD+ and hand it back. They consume it. Every time a sirtuin acts on a protein, or a PARP responds to damaged DNA, a molecule of NAD+ is spent.
Which means a cell’s NAD+ supply is not only an energy currency. It is a shared budget, drawn on by DNA repair, by gene regulation, by the machinery that responds to cellular stress.
You can see immediately why that idea caught fire. If the budget shrinks, what gets cut first? Researchers are working on exactly that, and if the link between NAD+ availability and cellular ageing holds up in humans the way it has in cell and animal work, it would reframe a great deal of what we assume about why tissues decline. That is a big if, and it is the most interesting open question in this catalogue.
Handling and storage
Freely soluble in water. White to off-white powder, and hygroscopic, so let the vial reach room temperature before opening or you will condense moisture straight onto it.
Storage is minus twenty, same as the peptides, kept dry and out of the light. Solutions come out acidic, around pH 3, which is expected.
What to check on your certificate
The content assay as well as the HPLC purity, since they answer slightly different questions. The water content, because a hygroscopic compound that has had a rough journey shows it there first. And the batch reference against the vial.
Regulatory position in the UK
Supplied as a laboratory reagent. NAD+ itself is a separate thing from the NAD precursor supplements sold on the high street, which sit under food law and are not what we supply.