Topical Vitamin C in Skin Care

New studies identify ultraviolet A (UVA) (320 to 400 nm) radiation as a key culprit in photoaging and aggressive skin cancers. Unfortunately, UVA protection is not available in all sunscreens, and when such protection is available, the screening agents do not offer complete protection. Under current Food and Drug Administration regulations, a sunscreen can be labeled “broad-spectrum” if it protects skin from any UVA radiation—no matter how small the amount. UVA is more than 30 times more present in sunlight than ultraviolet B (UVB) (290 to 320 nm). Furthermore, in comparison with UVB, UVA is more evenly present throughout the year. Moreover, it can pass through glass—including home, office, and car windows. UVB is virtually completely absorbed in the top 0.1 mm of skin; UVA can penetrate into deeper layers and through skin. UVA is especially dangerous because it is more effective than UVB at generating reactive oxygen species. Reactive oxygen species are a family of small, oxygen-based molecules that either contain an unpaired electron or are capable of forming one. Reactive oxygen species are generated by not only ultraviolet radiation but also other environmental insults (including smoke, pollutants, pesticides, herbicides, heat, and cold). Duke University has patented a stable, concentrated solution of l-ascorbic acid that delivers higher doses of vitamin C into skin than can be achieved by diet. New studies show that topical vitamin (L-ascorbic acid) is an excellent antioxidant for UVA and UVB (290 to 320 nm) protection, making it a useful adjunct to (but not replacement for) sunscreens.1 Vitamin C is one of the body's primary protectants from reactive oxygen damage, but it is depleted during ultraviolet injury. Vitamin C serves as the major aqueous phase antioxidant …