Nicotinamide (NAM), also known as niacinamide, is a form of vitamin B3 found in food and used as a dietary supplement and medication.As a supplement, it is used by mouth to prevent and treat pellagra (niacin deficiency). While nicotinic acid (niacin) may be used for this purpose, nicotinamide has the benefit of not causing skin flushing. As a cream, it is used to treat acne.