About Vitamin C
Topical vitamin C is claimed to inhibit ultraviolet radiation-induced damage to porcine skin. Vitamin C (ascorbic acid) functions as a biological co-factor and antioxidant. It has been touted as important in treating pathologies ranging from cancer to the common cold, presumably due to its antioxidant functions.
As previously noted, UV-radiation damage to the skin is due, in part, to the generation of oxygen free radicals. Topical application of vitamin C is shown to significantly elevate cutaneous levels of this vitamin in pigs. This protects the skin from UVB damage, as measured by erythema and sunburn cell formation. This biochemical protection is due to the reducing properties of the molecule. Further, the investigators show that topical ascorbic acid treatment can significantly retard UVA-mediated damage to the skin, and may thus serve as a biologically based, broad-spectrum photoprotectant and/or anti-inflammatory.
The investigators also provide evidence that the skin's vitamin C level can be severely depleted after UV irradiation. This would lower the skin's innate protecting mechanism as well as leave it at risk to poorer healing after photoinduced damage. Thus, the prophylactic activity of topical vitamin C therapy may prove valuable in lessening UV-induced trauma as well as other skin pathologies.
A subsequent study on humans, led by the same group, showed that topical vitamin C treatment did indeed reduce UVB radiation-induced erythema. This result suggests that free radials are indeed involved in UV damage to human skin, and that vitamin C can provide phophylactic photoprotection.