Nicotinamide adenine dinucleotide (NAD⁺) and nicotinamide adenine dinucleotide phosphate (NADP⁺) are the coenzymes derived from dietary nicotinamide, niacin, and tryptophan. Nicotinamide is deaminated in the body as niacin. Niacin is further converted through a series of reactions to NAD⁺ and NADP⁺. Finally, tryptophan produces quinolonate, which then produces nicotinamide and ultimately NAD⁺ and NADP⁺.

For the synthesis of NAD⁺, phosphoribosyl pyrophosphate and ATP provide ribose phosphate and AMP moiety. Glutamine provides the amino group. In the structure of coenzymes, nitrogen atom of nicotinamide possesses a positive charge because it forms an extra bond. Nicotinamide, which is formed from the degradation of NAD⁺ and NADP⁺, is excreted in urine as N-methyl nicotinamide.