“Vitamin C (or ascorbic acid) is a powerful antioxidant that is proven to not only protect against skin damage but also reverse some of the existing damage that has already been caused by oxidative stress—the process that damages cells, proteins, and DNA, resulting in premature skin aging, loss of collagen, pigmentation, and the formation of lines and wrinkles,” says Dr. Hall. According to Cho, Korean vitamin C uses “L-ascorbic (pure vitamin C) acid, which is more effective but harder to stabilize and protect it against degradation from exposure to light and oxygen.” “Yes, Korean vitamin C serums can help brighten hyperpigmentation and fade dark spots to even out skin tone, particularly for mild-to-moderate discoloration,” says Dr.