How do NAD+ supplements work?
The body makes most of its NAD+ from two sources: tryptophan and vitamin B3. While niacin and nicotinamide are among the most popular forms of B3 used in common vitamin supplements, a third form of B3 — nicotinamide riboside (NR) — converts into NAD+ more efficiently in the body.
But NR doesn’t just magically become NAD+. It first makes its way into your cells and becomes nicotinamide mononucleotide or NMN, which then becomes NAD+. That’s the purported advantage of NMN: it’s one step further along the path to becoming NAD+.