Clinically Proven to Support Good Cholesterol (HDL). The #1 Niacin Supplement with Nicotinic Acid. Helps Maintain Good Cholesterol (HDL) within the Normal Range. HDL is an Important Factor in Heart Health. Polygel System Designed to Minimize Flushing. Slo-Niacin® Tablets are manufactured utilizing a unique polygel controlled-release delivery system. This exclusive technology assures the gradual and measured release of niacin (nicotinic acid) and is designed to reduce the incidence of flushing and itching commonly associated with niacin use.