No Flush Niacin is an essential B-Vitamin (B-3). Niacin is involved in the normal metabolism of fats and fat-like substances such as cholesterol.Niacin taken in a single 500 mg dose, often causes flushing or itching. Carlson Niacin-Time is prepared by a patented process which minimizes these unpleasant side effects, often resulting in no flush.Each Niacin-Time tablet provides a gradual release of Niacin over a period of 5 to 7 hours.