How it works: Vitamin C is an antioxidant that helps to protect skin from damage resulting from ultraviolet rays and pollution. Vitamin C is the body's major natural aqueous antioxidant. Vitamin C is also a known cofactor that is

important in collagen production. In addition, vitamin C inhibits tyrosinase (a chemical involved in the creation of melanin and skin pigment) thus decreasing pigment synthesis. Finally, vitamin C also can help with the skin's natural barrier function by stimulating the production of sphingolipids, a substance that helps to retain the skin's natural moisture. While vitamin C can be taken by mouth as a vitamin supplement, only certain levels can reach the skin. These levels can successfully be increased with the topical application of vitamin C products.

Effectiveness: To be effective, vitamin C must be in the form of L-ascorbic acid and is best absorbed at a pH of less than 3.5 at a concentration of no greater than 20%. When formulated correclty, topical vitamin C has been shown to decrease the harmful effects of ultraviolet radiation and sunburn cell formation. In addition, studies have shown increased levels of many of the substances involved in collagen production. Other studies show an advantage to products containing vitamin C and other antioxidants like vitamin E. So, while vitamin C should be looked at primarily as a product to help with further skin damage, it also has many properties to help reverse pre-existing photoaging and sun damage.

Where to find it: Vitamin C can be found in many products including those from SkinCeuticals, Cellex C, Emergin C, and Citrix

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