Obagi Professional-C Serum 20% uses advanced scientific formulas developed and tested by leading Vitamin C experts. Obagi Professional-C 20% offers maximum daily antioxidant protection and greater penetration than other Vitamin C products. The greater the penetration, the greater the antioxidant benefit to your skin.
Vitamin C neutralizes free radicals to prevent skin cell damage. Professional strength Vitamin C can give your skin the superior protection it needs to:
 
Prevent premature signs of aging, including fine lines and wrinkles
Protect against future damage
Stimulate collagen production for firmer, more resilient skin
Lighten and brighten skin for more even tone