1. A method for treating an insulin resistance disorder in a subject in need thereof, comprising administering to the subject
nicotinamide riboside or a nicotinamide riboside analog represented by formula A:
wherein R represents independently for each occurrence H, acetyl, benzoyl, acyl, phosphate, sulfate, (alkyoxy)methyl, triarylmethyl,
(alkyl)(diaryl)silyl, or (triaryl)silyl; and X represents 0 or S, at a concentration of 1 nM to 10 ?M,
wherein the subject is a human subject.