Niacin (vitamin B3) is an important water-soluble vitamin that exists in two forms:niacin and nicotinamide. Niacin is the precursor of NAD+and NADP+,two important coenzymes for body anabolism and catabolism. NAD+and NADP+ are found in every cell and play a central role in metabolism and energy conversion.Niacin is also known for its anti-lipolytic effects via HCA2 receptors.