The Obagi Professional-C Serum 10% is a formulation that uses stabilized ascorbic acid . This product contains a form of Vitamin C that that can be easily absorbed by the skin. Vitamin C promotes collagen production to smooth the appearance of fine lines and wrinkles. The ingredient also brightens skin and promotes a more even tone. For those who have dry, sensitive, or reactive skin this serum will protect your skin from collagen synthesis and the sun.