NAD+: the coenzyme at the centre of ageing research

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Prepared by: Research Desk. Sources are linked for verification.

Published 19 October 2026

At a glance

Type: dinucleotide coenzyme (not a peptide), present in every living cell
Discovered: first described by Arthur Harden and William John Young in 1906
Research stage: a mature field in basic biochemistry; an active field in ageing research
Regulatory status: NAD+ itself is not an FDA-approved drug

What NAD+ is

Nicotinamide adenine dinucleotide is made of two nucleotides joined through their phosphate groups: one carries the base adenine, the other carries nicotinamide. It exists in an oxidised form (NAD+) and a reduced form (NADH). NAD+ is not a peptide, although it is often sold and discussed alongside peptides in the research-reagent market.

Research history

Harden and Young described a heat-stable "coferment" in yeast extracts that was needed for fermentation in 1906. Over the following decades, work by Hans von Euler-Chelpin, Otto Warburg and others identified its structure and its role as a hydrogen carrier in redox reactions. For most of the twentieth century NAD+ was studied mainly as a cofactor of metabolism.

From around 2000, interest shifted. Researchers found that NAD+ is also consumed by signalling enzymes, in particular the sirtuins and the poly(ADP-ribose) polymerases (PARPs). This linked NAD+ levels to gene regulation, DNA repair and ageing biology. Reviews by Verdin (2015) in Science, Rajman et al. (2018) in Cell Metabolism and Covarrubias et al. (2021) in Nature Reviews Molecular Cell Biology summarise this shift.

Mechanisms studied in preclinical work

Redox chemistry. NAD+ accepts electrons in glycolysis, the citric acid cycle and fatty acid oxidation, becoming NADH, which then feeds electrons into the mitochondrial respiratory chain.
Sirtuins. These NAD+-dependent deacylases remove acetyl and other groups from proteins, including histones, and are linked to metabolic regulation in model organisms.
PARPs. Poly(ADP-ribose) polymerases use NAD+ to signal DNA damage and recruit repair machinery.
CD38. This enzyme, found on immune cells and other tissues, breaks down NAD+, and its activity rises with age in mice.
Age-related decline. Studies in rodents and some human tissues report that NAD+ levels fall with age. In animal models, raising NAD+ through its precursors has been linked to changes in metabolic and age-related measures.

The links between NAD+ and ageing come mainly from animal and cell research, and their relevance to people is still under study.

The published research landscape

The NAD+ literature is large. It includes basic enzymology, studies of NAD+ synthesis and salvage pathways, and animal studies using precursors such as nicotinamide riboside (NR) and nicotinamide mononucleotide (NMN). Human research is growing but mostly consists of small, short trials of precursors measuring NAD+ levels in blood and safety markers. Few human trials have studied NAD+ itself rather than its precursors, and results on functional outcomes have been mixed.

Measuring NAD+ is also a research challenge. Levels differ between tissues and cell compartments, and blood measurements do not necessarily reflect levels inside muscle or brain cells.

Regulatory status

United States. NAD+ is not an FDA-approved drug. Its precursors have a separate and evolving regulatory history as dietary ingredients, which is outside the scope of this research overview.
Sport. NAD+ is not named on WADA's Prohibited List as of 2026.
Research-grade material. NAD+ sold as a laboratory reagent should come with batch documentation. NAD+ is sensitive to moisture, light and temperature, so storage conditions affect the integrity of laboratory material.

Open research questions

Uptake. Whether extracellular NAD+ enters cells intact, or is first broken down into smaller precursors outside the cell, is still being studied and may differ between cell types.
Compartments. NAD+ pools in the cytoplasm, nucleus and mitochondria are partly separate, and researchers are still working out how they exchange.
Cause or consequence. It is not yet settled whether the age-related fall in NAD+ drives ageing processes or mainly reflects them.
Consumers versus producers. The relative importance of rising NAD+ consumption, for example by CD38, and falling synthesis is an active question.

Limitations of the evidence

Most evidence for links between NAD+ and ageing comes from animal and cell models.
Human studies are mostly small precursor trials with biomarker outcomes.
NAD+ measurement methods vary, which makes studies hard to compare.

Where researchers source it

Purita is a store that lists NAD+ for laboratory research use only. Its product page carries the label "For Research Use Only. Not for human or animal administration."

Purita product page

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