Vitamin B3 or niacin, is a vitamin that is needed by the body, and is one of eight kinds of Vitamin B. Almost all types of Vitamin B, can help the body convert carbohydrates into sugar or glucose, which can be burned for energy. Also known as Vitamin B Complex, B3 Niacin is needed to help the body break down protein and fat. Humans need vitamin B3, ranging from 5-15 mg / day with a peak limit of