Niacin is a jazz fusion band started by bassist Billy Sheehan with drummer Dennis Chambers and keyboardist John Novello. Sheehan was a member of the American rock band Mr. Big. Founded in 1988, the band's name comes from the timbral foundation of the Hammond B3 organ; vitamin B3 is also known as niacin.
Niacin released its first album in 1996. Their third studio album Deep (2000) included vocals by Glenn Hughes of Deep Purple and guitar by Steve Lukather of Toto.