Nutritional Health! An Essential B-Group Vitamin Necessary for Good Health! NOW Flush-Free Niacin Is Formulated To Avoid Tingling Red Rash Reactions On The Skin !An Essential B-Group Vitamin Necessary For Good Health! Niacin (Vitamin B-3) 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. Note: Manufacturers continually change product specifications. While we try our best to keep product descriptions up to date, they do not necessarily reflect the latest information available from the manufacturer. We are not responsible for incorrect or outdated product descriptions and/or images.