Niacin Best Antioxidant Anti-Ageing Hydration Niacin description Niacin, also known as nicotinic acid, is one of two types of vitamin B3, the other being niacinamide. Like niacinamide, it is an anti-ageing ingredient with potent antioxidant benefits. Related ingredients: Nicotinic Acid Niacinamide Nicotinamide Vitamin B3