Sk Ultimate Antioxidant Facial Serum An antioxidant-and vitamin-rich serum that hits the ABC's of skincare: Vitamin A (Retinol), Vitamin B3 (Niacinamide), Vitamin C (Ascorbic Acid), and Vitamin E (Tocopherol). All the powerhouse players in an effective facial serum that penetrates where it is needed, to help improve the appearance and balance of the skin. Product