Vitamin C Serum Just a few drops of SkinCeuticals antioxidant serum a day can help keep fine lines, wrinkles, discoloration and even acne away (depending on the formula you choose). Formulated with synergistic combinations of potent antioxidants for optimal protection against free radicals generated by UV rays, pollution, infrared radiation and lifestyle factors, these serums feature 10% to 15% L-ascorbic acid (the purest form of vitamin C) and are designed to address specific skin concerns. Choose the award-winning C E Ferulic to target fine lines and wrinkles, Phloretin CF for discoloration and uneven skin tone, or Silymarin CF for oily or acne-prone skin.