Kojic acid is a by-product of rice wine manufacturing that is often used as a skin-lightening ingredient in cosmetics. It's usually found in concentrations of 1 percent applied in creams to your face or hands. Although not an overnight cure, it can be effective in helping to even out your skin's blotchiness and discolorations.
Identification
Kojic acid was discovered in Japan in 1989 and is derived from a mold known as aspergillus oryzae that is grown on rice. After researchers discovered its skin-lightening properties, it was quickly formulated into cosmetics. It isn't particularly stable on its own, so it's often combined with other ingredients to achieve the best effects. It's most often found in creams, soaps and lotions. Kojic acid dipalmitate is a separate compound of kojic acid that is also used to fight freckles, sun-spots, pregnancy marks and other pigmentation problems.
Effects
The European Commission Scientific Committee on Consumer Products reported that kojic acid is effective for inhibiting melanin production and also possesses weak antimicrobial properties. It attacks pigment-causing melanin in your skin by shutting down the effects of the amino acid tyrosine that creates melanin. Kojic acid also reduces the existing melanin in your skin and helps to depigment the skin.
Time Frame
Results can vary from one person to another, but it can take three to eight weeks before you notice a difference. Some patients haven't seen results for up to a year or longer. You should stop lightening when you've achieved your desired effects, or you may end up with areas of the skin lighter than normal skin tone.
Considerations
Natural kojic acid by itself turns a shade of brown when exposed to air or sunlight and loses its effectiveness, one reason you should avoid using it in this state. You will need to be vigilant about applying a sunscreen while using a skin lightener or else you will negate the product's effects when UVA and UVB rays from the sun darken your skin.
Warning
Research, including a study conducted by Tamotsu Takizawa, et al, published in "Toxicological Sciences" in June 2004, and another conducted by Hiroshi Suzuki, et al, and published in "Mutation Research" in June 2005, indicates that kojic acid may have some carcinogenic properties. Other studies on animals have shown brain, nervous system or behavioral side effects with high doses of kojic acid. A study by Mikio Nakagawa, et al, published in the journal "Contact Dermatitis" in January 1995, also confirmed that kojic acid can lead to dermatitis in some people.
