Vitamin C is considered a stable and effective antioxidant for skin. For skin lightening sevelral studies have shoes Vitamin C can have benefit for inhibiting melanin production. What complicates the issue of vitamin C is that the vitamin has many forms, and these are used in skin care products in a wide variety of concentrations. Some of these options may be magnesium ascorbyl phosphate, L-ascorbic acid, ascorbyl glucosamine, and ascorbic acid. While the amount of research isn’t definitive the vitamin offers other benefits along with its skin-lightening ability.
Still, there are very few studies showing any of these to have benefit for inhibiting melanin production and the tests that do exist used concentration far greater than what shows up in most skin care products. Generally the amount of vitamin C in these studies ranges from 5% to 10%, while most skin care products containing vitamin C use less than a 1% concentration.
