As one of the most powerful antioxidants in the skin, vitamin C has been shown to protect against photo-aging, ultraviolet-induced immunosuppression, and photocarcinogenesis. It also has an anti-aging effect by increasing collagen synthesis, stabilizing collagen fibers, and decreasing collagen degradation. It decreases melanin formation, thereby reducing pigmentation. Vitamin C is the primary replenisher of vitamin E and works synergistically with vitamin E in the protection against oxidative damage.