NAD+ Explained: The Coenzyme Behind Cellular Energy and Repair Research

NAD+ is not a peptide, but it sits alongside peptides in many research catalogues because of its central role in metabolism and ageing biology. This guide explains the biochemistry in plain English.

What NAD+ is

Nicotinamide adenine dinucleotide (NAD) is a coenzyme found in every living cell. It exists in two forms:

• NAD+, the oxidised form, which accepts electrons
• NADH, the reduced form, which carries electrons to the mitochondria

That shuttle drives energy production in glycolysis, the TCA cycle and oxidative phosphorylation.

NAD+ as a substrate, not just a carrier

NAD+ is also used up by several important enzyme families:

• Sirtuins — deacetylases involved in metabolism, stress responses and gene regulation
• PARPs — enzymes that help repair DNA damage
• CD38 — an immune-cell enzyme that breaks down NAD+ and whose activity rises with inflammation

Because these enzymes consume NAD+, cells have to keep regenerating it.

How cells make NAD+

• The salvage pathway recycles nicotinamide back into NAD+ through the enzyme NAMPT. This is the main route in most tissues.
• De novo synthesis builds NAD+ from tryptophan.
• Precursors such as nicotinamide riboside (NR) and nicotinamide mononucleotide (NMN) enter the salvage pathway part-way through.

5-Amino-1MQ is studied because it inhibits NNMT, an enzyme that removes nicotinamide from the salvage pool.

Why ageing research focuses on NAD+

Several studies report that tissue NAD+ levels fall with age, possibly because of rising CD38 activity and greater DNA-repair demand. Whether restoring NAD+ reverses age-related changes is an active and still-open research question.

Related compounds

MOTS-c and SS-31 are studied in the same mitochondrial context through different mechanisms.

Comparing NAD+ listings

1. Check the form. NAD+ (oxidised) and NADH are different products, and some listings don't make clear which they contain.
2. Check purity and storage. NAD+ breaks down in solution and with heat, so storage and shipping conditions matter.
3. Compare price per mg on our NAD+ comparison page. NAD+ is often sold in large vial sizes.

Summary

NAD+ is a central coenzyme in energy metabolism and a substrate for DNA-repair and signalling enzymes, which is why it features so heavily in ageing research. PeptideCompare provides no dosing or usage guidance, and nothing here is for human or veterinary use.