Niacin, also called vitamin B3, is a group of compounds (such as nicotinic acid and nicotinamide, both included in MAXD). It assists a variety of enzymes in the body, contributing to energy production and cell communication. Niacin also helps support healthy skin, promotes normal cognitive function, and aids in reducing fatigue and tiredness. Natural sources of niacin include fish, meat, mung beans, peanuts, and mushrooms.