β-Nicotinamide mononucleotide powder is a product of the extracellular Nicotinamide phosphoribosyl transferase (eNAMPT) reaction and a key NAD+ intermediate. It ameliorates glucose intolerance by restoring NAD+ levels in HFD-induced T2D mice. It also enhances hepatic insulin sensitivity and restores gene expression related to oxidative stress, inflammatory response, and circadian rhythm, partly through SIRT1 activation.