Kojic acid was discovered in Japan in 1907 from a fungus growing on steamed rice. Today, however, it's created as a byproduct of rice fermentation when making Japanese sake wine. It's used widely in cosmetics due to its skin-lightening properties and is also a component of antibiotics, insecticides and pesticides. Scientists have isolated over one hundred and fifty various kojic acid derivatives, many of them chemicals never synthesized before, which are showing promise to treat a variety of health conditions.
Anti-inflammatory
A study at the Institute of Bioscience and Biotechnology in the Republic of Korea, published in April 2010 in the journal "Pharmacies," tested several of the newly-synthesized kojic acid derivatives in the lab. They found anti-inflammatory properties in the acid that showed promise as a cancer drug due to their ability to inhibit cancer cell proliferation. An earlier study at the Slovak Academy of Sciences Institute of Experimental Endocrinology demonstrated that kojic acid extracts may represent a new class of compounds with anti-leukemia activity.
Antimicrobial
As bacteria develop resistance to a wide variety of drugs, scientists continue to try and find new medicines to combat these "super bugs." The August 2006 issue of the "International Journal of Agriculture and Biology" reported on a study investigating kojic acid's effects against several strains of bacteria and fungi that found the acid to be even more effective as an antimicrobial than the prescription antibiotics ceftazidime and nitrofuranatoin.
Dermatitis
Although generally safe, one of the negative effects of kojic acid is the fact that it can cause contact dermatitis in sensitive individuals. A 2006 issue of the journal "Contact Dermatitis" reported on a study that included five kojic-acid-sensitive patients, aged 34 to 58 years, who developed facial dermatitis one to 12 months after starting the application of kojic-acid-containing cosmetic products. If you have sensitive skin or a condition such as rosacea, you should use caution when trying products containing kojic acid.
Skin Lightening
One of the primary uses for kojic acid is in skin-lightening products, since the acid prevents the formation of melanin, the pigment in skin, although it can take from three to six months of use before you see any results. Kojic acid is also highly effective in reducing the pigment in patients with melasma, a dark skin discoloration that appears on sun-exposed areas of the face or on the skin of pregnant women.
Thyroid
There are conflicting studies about the effects of kojic acid on the thyroid. One project showed that thyroid lesions and benign tumors were reported when male rats were fed up to 4 percent kojic acid for 12 to 20 weeks, according to the Scientific Committee on Consumer Products. However, another report in the February 2001 issue of "Regulatory Toxicology and Pharmacology" concluded that the risk of inhibition of iodine uptake and thyroid tumors caused by kojic acid in humans appears to be extremely low. To be safe, if you suffer from thyroid disease and are on thyroid medications, you should check with your doctor before using kojic acid.
References
- Scientific Committee on Consumer Products: Kojic Acid
- Contact Dermatitis: Contact Allergy to Kojic Acid in Skin Care Products
- "Regulatory Toxicology and Pharmacology"; Evaluation of Health Aspects of Kojic Acid in Food; Burdock GA, Soni MG, Carabin IG; February 2001
- "International Journal of Agriculture & Biology"; Cultural Conditions Studies on Kojic Acid; S. A. El-Aasar; August 2006
- Optiderma: Mushrooms in Skincare: What is Kojic Acid?
