Obagi Professional-C Serum 10% Description: A concentrated anti-aging serum for all skin types. Obagi Professional-C Serum 10% infuses your skin with L-ascorbic acid, the only form of vitamin C suitable for topical application. Designed to penetrated deep into your skin, this formula provides effective antioxidant protection from UV damage as it brightens away hyperpigmentation and encourages the growth of collagen and elastin fibers.