Effective in repairing the free radical damage, Obagi Professional C serum 20% is infused with L-ascorbic acid, the only form of vitamin C suitable for topical application, which repairs the skin and gives a healthy glow. Professional C Serum deeply penetrates into the skin and provides effective antioxidant protection from UV damage as it gently eliminates hyperpigmentation and stimulates the growth of collagen and elastin fibres.