Vitamin C (L-ascorbic acid) is a natural exfoliant and antioxidant that’s found in citrus fruits and dark green leafy vegetables. It can reduce the signs of sun-damage on the skin, as well as decrease the appearance of brown patches. Because vitamin C is essential for both stimulating the production of collagen and the protection of cell membranes, this key ingredient has the ability to defend against free radical damage, and thereby, exert restorative effects to the skin. The stability and effectiveness of products containing this agent depends upon the type of vitamin C, how the preparation is formulated, and more importantly, on the concentration of the key active. Vitamin C is one of few topical agents whose effectiveness against wrinkles and fine lines is supported by scientific research. However, the practical use of vitamin C in skin care products presents difficulties due to its instability when formulated. Upon exposure to air, vitamin C undergoes oxidation and becomes ineffective, or even potentially harmful (oxidized vitamin C may increase the formation of free radicals). Stabilized commercial preparations are available, but they must be properly used and stored in order to maintain their effectiveness. Advances in vitamin C research has produced newer derivatives, such as ascorbyl palmitate and magnesuim ascorbyl phosphate, that appear to have improved skin penetration and efficacy.
