Kojic acid is produced by several varieties of fungi, and is a by-product of the fermentation process of malting rice – used in the manufacture of the Japanese rice wine, sake. It is used in cosmetics to lighten skin by inhibiting or interrupting the skin’s production of melanin.The production of melanin is what determines skin pigmentation.

Melanin production is mainly determined by genetics, but can vary due to the body’s response to both internal and external factors. Pregnancy hormones, stress, sun exposure, and inflammation can all cause increased melanin production. Kojic acid interferes with melanin production, helping to lighten the skin.

Kojic acid is also known for its antioxidant, antibacterial, and antifungal properties.

Kojic acid has been used increasingly as a replacement for hydroquinone. Hydroquinone, while an effective skin lightening agent, can be irritating to some skin types.