What they are
Sirtuins are a family of NAD+-dependent enzymes (SIRT1–7 in humans) that modify proteins to regulate metabolism, DNA repair, inflammation and stress responses.
Why they matter for longevity
Because they require NAD+ to function and are activated by states such as fasting and caloric restriction, sirtuins are a proposed link between nutrient status and healthy ageing. They underpin much of the interest in NAD+ boosters and certain plant compounds.
What the evidence shows
Sirtuin biology is robust in cells and animals, but human longevity claims are not established, and some early findings around specific sirtuin-activating compounds have been contested. Mechanistic promise has not yet translated into proven human life extension.
Bottom line
An important and well-studied pathway — a reason to be interested, not evidence that any “sirtuin-activating” product extends human lifespan.