[noun] Niacin or vitamin B3 is composed of two compounds: nicotinic acid and nicotinamide, which have the same biological activity. They are precursors of enzymes essential to many metabolic reactions: DNA repair, energy production within cells, manufacture of certain lipids, etc. Niacin is naturally present in many plant- and animal-sourced foods, including poultry, oily fish and peanuts.

Related category: Nutri-cosmetics.