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Medically reviewed by Vanessa Niles, R.N., M.D., F.A.C.O.G. —
Definition
Sirtuins, in plain English
Sirtuins are named after the yeast protein Sir2. NIH's Genetic Testing Registry describes SIRT1 as a member of the sirtuin family, related to yeast Sir2.
Each time a sirtuin removes an acetyl group (or a similar tag) from a protein, it uses up one NAD+ and releases nicotinamide. Different sirtuins work in the nucleus, the cytoplasm and the mitochondria.
- In humans
- 7 (SIRT1–SIRT7)
- Fuel
- NAD+
- By-product
- Nicotinamide
How it connects
How sirtuins relates to NAD+
Because sirtuins depend on NAD+, their activity rises and falls with NAD+ levels. That link is a major reason scientists study NAD+ in aging (Imai and Guarente, 2014).
For your treatment
What sirtuins means for NAD+ therapy
Whether raising NAD+ boosts sirtuin activity in people, or improves health through sirtuins, hasn't been proven in clinical trials.
- Free online consultation with a licensed U.S. provider
- NAD+ nasal spray or injection, plans from $166 a month if prescribed
- NAD+ has no FDA-approved use; compounded NAD+ isn’t FDA-approved
Questions
Sirtuins: common questions
What are sirtuins?
Sirtuins are a family of seven enzymes in people (SIRT1 to SIRT7) that need NAD+ to work. They remove chemical tags from proteins and help regulate metabolism, stress responses and DNA upkeep.
Do sirtuins slow aging?
In yeast, worms and mice, sirtuins have been linked to lifespan and metabolism, but that hasn't been shown in people.
What do sirtuins need to work?
NAD+. Without it, they can't remove protein tags, so their activity depends on how much NAD+ is available.
Does NAD+ therapy change how these enzymes work in people?
That hasn't been shown. Most research on NAD+ enzymes comes from cells and animals.
Are there medicines that target NAD+ enzymes?
Yes, in cancer care: PARP inhibitors treat some cancers, and a CD38 antibody (daratumumab) treats multiple myeloma. They aren't used to raise NAD+.
Why does enzyme research matter for NAD+ therapy?
It explains why NAD+ is worth studying. Plausible biology isn't the same as proof that NAD+ therapy helps people.
Keep learning
Related NAD+ terms
Terms that connect to sirtuins, each explained on its own page.
- MoleculesNAD+NAD+ is the oxidized form of nicotinamide adenine dinucleotide, a coenzyme found in every living cell. It carries electrons for energy metabolism and is used by enzymes involved in DNA repair.
- Enzymes & pathwaysPARPsPARPs (poly(ADP-ribose) polymerases) are enzymes that respond when DNA is damaged. They use NAD+ to build chains of ADP-ribose that flag the damage and call in repair proteins.
- Enzymes & pathwaysCD38CD38 is an enzyme on the surface of many cells, especially immune cells, that breaks down NAD+. Studies in mice suggest rising CD38 is a key reason NAD+ falls with age.
- Enzymes & pathwaysNAD+ salvage pathwayThe NAD+ salvage pathway recycles nicotinamide, which is released whenever enzymes use NAD+, back into NAD+. It's the main way most human cells keep their NAD+ supply topped up.
Official sources
Sirtuins: sources and official resources
Official government and research sources behind this page, so you can check the facts yourself.
- NIH Genetic Testing RegistrySIRT1 sirtuin 1 (gene)
Gene summary for SIRT1, a member of the sirtuin family related to yeast Sir2.
- NIH PubMedImai and Guarente. NAD+ and sirtuins in aging and disease (2014)
Review of how sirtuins depend on NAD+ and why that matters for aging research.
- NIH PubMed CentralCovarrubias et al. NAD+ metabolism and its roles in cellular processes during ageing (2021)
Review of how NAD+ works in cells and how levels change with age.
- NIH Office of Dietary SupplementsNiacin: Health Professional Fact Sheet
Explains how the body turns niacin (vitamin B3) into NAD, a coenzyme used by more than 400 enzymes.
Medically reviewed by Dr. Vanessa Niles, R.N., M.D., F.A.C.O.G., on October 12, 2026. This glossary is general education, not medical advice. NAD+ has no FDA-approved use, and compounded NAD+ is not FDA-approved or evaluated by the FDA for safety or effectiveness. Talk with a licensed provider before starting any supplement or treatment.
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