Kojic acid is derived from a variety of fungi and organic substances and is present in skin-whitening creams used to diminish dark areas resulting from excessive pigmentation in the skin. You can buy raw kojic acid but this substance may cause damage to your skin unless it is diluted in a cream or gel. Kojic acid may help diminish or eliminate sun freckles, melasma or other pigmentation when used correctly, although skin conditions and their treatment should always be discussed with a health care professional before beginning a treatment program.
Besides freckles and melasma there are many types of pigmentation problems that may be treated with kojic acid, because it stops the production of pigment. Kojic acid attacks the root of the pigmentation source by inhibiting the production of melanin. More specifically, kojic acid counters the antioxidant properties of the enzyme tyrosinase, which reacts with an amino acid called tyrosine to produce melanin. By stopping the production of melanin, kojic acid can reverse excessive darkening of the skin.
All people have pigment-producing cells in our skin called melanocytes that produce melanin, which our skin uses to shield itself from the sun and other environmental hazards. While this pigment protects us from the sun, our melanocytes can become damaged if our skin receives too much sun exposure. The result of damaged melanocytes is often an abundance of melanin fed into the dermis. This process results in small brown spots called freckles. A component of kojic acid called kojic acid dipalmitate fights freckles topically by countering the melanin in the area to whiten the skin.
Melasma is a darkening of the skin, in larger sections than freckles, that is the result of over-productive melanocytes. Melasma darkens the skin of the face, usually affecting the apples of the cheeks, the forehead, the jawline and areas around the mouth. Melasma may occur due to overexposure to the sun or cellular hypersensitivity. For women, melasma may also be triggered by estrogen supplements, birth control pills and pregnancy. Kojic acid is found in several bleaching creams and gels designed for the reduction of melasma spots. If you have melasma, you should avoid the sun as much as possible and discuss using a kojic acid product with your health care provider.