Vitamin B3, also called Niacin, Niacinamide, or Nicotinic Acid, is an essential nutrient required by all humans for the proper metabolism of carbohydrates, fats, and proteins, as well as for the production of hydrochloric acid for digestion. B3 also supports proper blood circulation, healthy skin, and aids in the functioning of the central nervous system. Because of its role in supporting the higher functions of the brain and cognition, vitamin B3 also plays an important role in the treatment of schizophrenia and other mental illnesses. Lastly, adequate levels of B3 are vital for the proper synthesis of insulin, and the sex hormones such as estrogen, testosterone, and progesterone.