SkinCeuticals Serum 10 Dual Antioxidant Treatment - Vitamin C SerumSkinCeuticals Serum 10 Dual Antioxidant Treatment is a lightweight antioxidant serum, ideal for introducing antioxidants to sensitive or less tolerant skin. Formulated with 10% L Ascorbic Acid (pure Vitamin C) and 0. 2% Ferulic Acid, this SkinCeuticals antioxidant serum for sensitive skin helps protect skin from environmental damage and defend against premature ageing while leaving the complexion brighter, smoother and healthier looking.