what is niacine
Product Details. Niacin is a B vitamin, B 3. Nature Made Â® Flush Free Niacin 500 mg uses a type of Niacin that does not have the side effects of flushing commonly associated with some Niacin supplements.roduct Details. Niacin is a B vitamin, B 3. Nature Made Â® Flush Free Niacin 500 mg uses a type of Niacin that does not have the side effects of flushing commonly associated with some Niacin supplements.