A salt of ascorbic acid. It is used as a preservative and antioxidant to prevent rancidity. Vitamin C is thought to prevent collagen break down and help combat the signs of aging. As an antioxidant it is believed to remove the free radicals that cells produce. Free radicals have been associated with skin cancer and premature skin aging due to sun exposure. Some experts believe antioxidants are the most vital weapons in the fight against aging. Most of the damage of our skin is caused by a free-radical assault from smoke, pollution and UV rays. Free radicals then turn the oils of our skin rancid, which damages the collagen. Collagen is the protein fibers that serve as the building blocks of our skin. Antioxidants are used in skin care products to neutralize free radicals before they ravage the skin. Topical vitamin C may help lighten solar lentigos and melasma. Some studies have shown that topical vitamin C provides additional protection against the harmful effects of the sun. Said to prevent collagen breakdown, which would aid in combating aging. Duke University found that adding Vitamin C and E to sunscreens protects against UVB radiation.