Kojic Acid Good Antioxidant Dark Spot Fading Evens Skin Tone Anti-Ageing Kojic Acid at a glance By-product of the fermentation process of malting rice for use in the manufacture of sake Helps to brighten an uneven tone Contains antioxidant properties Has issues with stability when in formulations Kojic Acid description By-product of the fermentation process of malting rice for use in the manufacture of sake (Japanese rice wine). In vitro and in vivo research and animal studies have shown that kojic acid is effective for brightening an uneven skin tone. Kojic acid is typically used at concentrations between 0.1 to 2.0% but has been used in some products up to 4.0%. In 2010 the Cosmetic Ingredient Review Expert Panel concluded that kojic acid is safe for use in cosmetic products up to a concentration of 1%. It functions as a skin brightener by inhibiting the formation of melanin by inhibiting the enzyme tyrosinase. Kojic acid’s downside is that it’s an unstable ingredient in cosmetic formulations. On exposure to air or sunlight, it turns brown and loses its efficacy. Many cosmetics companies use kojic dipalmitate as an alternative because it’s more stable in formulations. However, there’s no research showing that kojic dipalmitate is as effective as kojic acid, although it’s a good antioxidant.