Niacin (vitamin B-3) is an essential B-complex vitamin. Many niacin supplements cause temporary flushing or red tingling on the skin due to niacin when taken in high doses. This flush-free niacin is formulated with inositol hexanicotinate, a form of niacin composed of six niacin molecules linked to a single inositol molecule. It is slowly broken down in the body to produce free niacin and inositol. This gradual release allows niacin to exert its benefits without causing a 'niacin flush,' a phenomenon intolerable for many people.