Vitamin C (L-ascorbic acid) is the body’s major aqueous phase antioxidant and is absolutely vital for life. All animals make their own vitamin C, except for humans and other primates, one species of Indian fruit-eating bat, and the guinea pig. In fact, a 130-pound goat synthesizes 13 grams of vitamin C per day, almost 200 times the American Food and Drug Administration (FDA) requirement (1). Not only do other animals make hundreds of times the vitamin C we ingest, but also, when under stress, they can make more than ten times their normal amount of vitamin C, a capability that we humans do not have (1).
Our skin is the organ that suffers most from environmental free-radical stress from exposure to sunlight, cigarette smoke, and other pollution. Furthermore, this contact actually depletes the level of vitamin C in skin. Even minimal UV exposure of 1.6 minimal erythema dose (MED) decreases the level of epidermal vitamin C to 70% of the normal level, and exposure to 10 MED decreases the vitamin C to only 54% (2). Exposure to 10 parts per million of ozone in city pollution decreases the level of epidermal vitamin C by 55% (3).