NAD+ is a coenzyme, or molecule, found in all living cells, and it plays a vital role in energy metabolism and maintaining proper cell functioning. It is particularly crucial for the functioning of our mitochondria, the power plants in our cells that turn our food and oxygen into en ergy. The problem is that our levels of NAD+ decline significantly as we get older (impairing mitochondrial functioning, among other things), and these declining levels drive the aging process. Which makes sense when you consider that underperforming or damaged mitochondria are thought to contribute to a number of age-related health conditions.

One way NAD+ seems to exert its health-promoting properties is by helping sirtuins do their job. Sirtuins are a class of proteins that regulate biological pathways, turn certain genes on and off, and help protect cells from age-related decline. For example, NAD+ increases the activity of one type of sirtuins, SIRT1, which has been found to induce the formation of new mitochondria and extend life span, as well as SIRT6, which helps maintain the length of telomeres (the end caps on DNA)—longer telomeres are associated with longevity.*