Reduced nicotinic acid riboside (NARH) is a form of nicotinic acid riboside. It's a type of vitamin B3 derivative. NARH can be converted to nicotinamide adenine dinucleotide (NAD+) in the body. NAD+ is crucial for various cellular processes, including energy production and DNA repair. NARH may have potential benefits in improving cellular health and combating age-related decline.