Niacin , also known as vitamin B 3 , is a water-soluble vitamin which prevents the deficiency disease pellagra . It is an organic compound with the molecular formula C 6 H 5 NO 2 . It is a derivative of pyridine , with a carboxyl group (COOH) at the 3-position. more

Niacin , also known as vitamin B 3 , is a water-soluble vitamin which prevents the deficiency disease pellagra . It is an organic compound with the molecular formula C 6 H 5 NO 2 . It is a derivative of pyridine , with a carboxyl group (COOH) at the 3-position. Other forms of vitamin B 3 include the corresponding amide , nicotinamide ("niacinamide"), where the carboxyl group has been replaced by a carboxamide group (CONH 2 ), as well as more complex amides and a variety of esters. The terms niacin, nicotinamide, and vitamin B 3 are often used interchangeably to refer to any one of this family of molecules, since they have a common biochemical activity. less