With Obagi-C Rx, you're on your way to healthier, refreshed, revitalized skin from cell to surface. Obagi-C Rx Systems promote skin rejuvenation from the inside out using a formulation of prescription-strength hydroquinone USP, 4%, which reduces the appearance of hyperpigmentation and age spots, combined with 10% L-ascorbic acid (Vitamin C)—the only topical antioxidant proven to stimulate collagen synthesis and protect your skin by minimizing future skin cell damage. The gradual bleaching of hyperpigmented skin conditions such as chloasma, melasma, freckles, senile lentigines, and other unwanted areas of melanin hyperpigmentation.