(BeWellBuzz) Niacin is obtained from the diet. Niacinamide can be synthesized in the body from niacin and tryptophan, an amino acid. Both niacin and niacinamide are available as supplements. From niacin the body synthesizes two co-enzyme forms, nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP). Both are essential in cell metabolism ... Continue Reading