SkinCeuticals C E Ferulic is a high potency serum with a combination of powerful antioxidants to protect skin against atmospheric ageing. 15% pure vitamin C (L-ascorbic acid), 1% vitamin E (alpha tocopherol), and 0.5% ferulic acid work in combination to protect against environmental damage and premature signs of ageing caused by free radical damage from UV rays, infrared radiation (IRA), and ozone pollution (O3).