NR (Nicotinamide riboside)

NR is a vitamin B3 form and NAD+ precursor that is metabolized via salvage pathways to increase NAD+, with NMN as a possible intermediate. Human trials reliably show that oral NR raises blood NAD+ and/or related metabolites and is well tolerated. Evidence for downstream clinical benefits, such as improved physical performance, metabolic health, or healthspan, is mixed and largely confined to small, short-duration studies.