Kojic acid is a natural extract found in mushrooms and is available in a variety of skin lightening products and bleaching creams.
Kojic acid prevents melanin (pigment in the skin) formation by inhibiting activity of the enzyme tyrosinase.
Kojic acid is used to treat freckles, age spots, and other skin pigmentation problems. It is used topically and works by soaking into the layers of the skin, where it can interact with cells and enzymes.
Kojic acid is available in many different forms, mainly in products for the face. Skin lightening facial peels (often called glycolic peels'), moisturizing gels, night creams, serums, and soaps are among the most common.
Kojic acid is unstable in many skincare formulations because when exposed to air or sunlight it turns brown and loses its effectiveness. It is best stored and used in glass ampoules, although it is also available in some traditionally-bottled night creams and moisturizers.
Kojic acid is generally free of side effects, but in concentrations over 1% some people experience increased skin sensitivity, contact dermatitis, and erythema.