Obagi Professional-C Serum 10% — 1 oz. Obagi Professional-C Serums use advanced scientific formulas developed and tested by Vitamin C experts to provide maximum daily antioxidant protection against free radicals, which cause premature signs of aging, including fine lines and wrinkles. Obagi’s formula provides greater penetration of ingredients, delivering greater antioxidant benefits to your skin. Obagi Professional-C Serums use stabilized L-ascorbic acid −− the only form of Vitamin C that can be effectively absorbed by the skin. Obagi Professional-C Serum 10% is for dry, sensitive or reactive skin. The 10% L-ascorbic acid formula helps in defending against damaging UVA and UVB rays and helps prevent premature signs of aging, such as fine lines and wrinkles. It also contributes to collagen synthesis. Formula for better skin penetrationAntioxidant protection to free radicals Hydrates skin and heals blemishesEspecially Suited For: Normal to dry skinEssential Elements: Obagi Professional-C Serum 10% comes in a 1-oz. bottle.For Best Effect: Apply 3 to 5 drops to the face, neck and chest using fingertips. Apply to cleansed skin in the morning before sunscreen and makeup application. A slight tingling may occur in some people, which diminishes with continued use.