Zein Obagi. Vitamin C functions as a potent antioxidant, neutralizing the consequences of no-fee oxygen radical groups. By minimizing this harm and revitalizing the formation of collagen and elastin, vitamin C bring skin's vitality and youthfulness. Vitamin C10 serum is a high end serum to reveal translucent skin from inside. Has highly focused vitamin C to smoothen skin with visible pores or maybe acne marks. The newer formulation fuses with vitamin E to maximize antioxidant performance. Contains vitamin E as well as 10 % fresh vitamin C (L-ascorbic acid). Penetrates deep into the skin, effectively driving vitamin C and E on the target area. Unique formulation and manufacturing process betters vitamin C balance. How to use: Apply morning and night after face wash and toner cartridge. Lightly squeeze 3-4 drops (for whole face) onto palm and gently use on face with fingertips, particularly to dark or dry locations.