Obagi C-Clarifying Serum (30 ml.)
C-Clarifying Serum is a prescription-only product that lists 4% hydroquinone as the active ingredient. It is formulated in a simple gel base that contains L-ascorbic acid, a form of vitamin C that has antioxidant benefits. The pH of this serum allows the vitamin C to be efficacious, but also potentially irritating. This is a definite option for lightening skin discolorations related to sun damage or hormones, but would have been even better if Obagi had included a roster of anti-irritants.