Vitamin B3, also known as niacin or nicotinic acid, is a water-soluble vitamin, used by the human body as nicotinamide (also called ‘niacinamide’) to form the coenzymes nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP). None of the forms are related to the nicotine found in tobacco, although their names are similar (1).

 

Since nicotinic acid can also be synthesized in humans from the amino acid tryptophan, it does not qualify as a vitamin provided that an adequate dietary supply of tryptophan is available.