The earlier you add a vitamin C product to your routine, the longer your complexion will remain youthful and radiant. Obagi Professional C Serum 20 is a concentrated serum with 20% vitamin C that provides multiple benefits for the complexion. This ingredient neutralizes free radicals that break down collagen and elastin causing damage and leading to fine lines, wrinkles and dark spots. Vitamin C also promotes collagen production which plumps skin and reduces the look of wrinkles. The formula is ideal for most skin types and it absorbs quickly without leaving the complexion greasy or oily.