Dietary Supplement Niacin is an essential B-vitamin necessary for good health. Many Niacin supplements cause a temporary Niacin flush or tingling red rash on the skin when taken in large doses. This flush-free Niacin is formulated to avoid such reactions. Inositol Hexanicotinate is a stable, non-flushing source of Niacin. This superior source, and lower potency, of Niacin works to reduce the problems associated with mega doses of Niacin supplements. Free of: sugar, salt, yeast, wheat, gluten, soy, milk, egg or preservatives. Vegetarian Formula.