Ascorbic acid 2-glucoside (AA-2G), an ascorbic acid (vitamin C) derivative shown in Figure 1, can be hydrolyzed by intestinal mal- tase and acts as ascorbic acid in humans.1 Because ascorbic acid has good free radical removal ability, it has been known as a good antioxidant and used in cosmetics to protect human’s skin from the damage caused by UV rays.2,3 In addition, ascorbic acid is a good tyrosinase inhibitor which reduces the formation of melanin.4 Therefore, ascorbic acid has often been used in cosmetics as a whit- ening ingredient.5 Because the stability of ascorbic acid was af- fected by the change of temperature and pH,6,7 these drawbacks limited the application of ascorbic acid in cosmetics. Compared to ascorbic acid, AA-2G is a more stable cosmetic ingredient that can be used an alternative in cosmetics.