Obagi Professional-C Serum 15%Supercharge your glow with a high performance vitamin C. This powerful daily antioxidant serum is made with 15% pure L ascorbic, the industry's gold standard of vitamin C to help defend all day from free radicals and works to brighten skin tone and reduce signs of past skin damage. Key Benefits: Formulation mastery, harnessing the power of L ascorbic acid A powerful antioxidant that fortifies the skin barrier defenses to help brighten, renew, and