Nutrition and Supplements Vitamins and minerals Now Foods Niacin Flush Free 250 mg Vegetable Capsules 90 Niacin (vitamin B-3) is an essential B vitamin necessary for good health. Flush-free Niacin contains Inositol Hexanicotinate, a form of niacin that contains six niacin molecules bound to a single inositol molecule. It is slowly broken down in the body to produce free niacin and inositol. This gradual release of niacin allows for true niacin activity without the characteristic niacin rush that many people cannot tolerate. Many niacin supplements cause a red niacin rash or rash when taken in large doses. This rinse-free niacin is formulated to prevent such reactions.