Mushrooms in Skincare: What is Kojic Acid?

Nutrition article posted on Apr 30, 2010 by Joséphine Beck, Digestive Care Advisor

Mushrooms have been used for thousands of years as food, for medicinal purposes, and more recently in skincare. Mushrooms are known to enhance the immune system and have lots of health benefits. Nowadays, they are also used in skincare products to improve the appearance of skin and reduce the signs of the aging process. Have you ever heard of Kojic Acid?

Let's learn a little bit more about this natural skin lightener found in Mushrooms.

What is Kojic Acid?
What is Kojic Acid Used for?
How does Kojic Acid Work?
Kojic Acid: Any Side Effects?
Also Read

What is Kojic Acid?

Kojic Acid is a by-product in the fermentation process of malting rice, for use in the manufacturing of sake, the Japanese rice wine (See Kojic Acid. Wikipedia.com).
Kojic Acid is fungal in nature, made by such fungi as Aspergillus oryzae, which is also an ingredient used in the fermentation of soybeans. The name "koji" is a common name for bacteria, meaning "culture" in Japanese.

What is Kojic Acid Used for?

Kojic Acid occurs in many fermented Oriental foods (Kinoshita et al. 1968), and possesses both antibacterial and antifungal activities. A mixture of ascorbic acid and Kojic Acid has been patented for use as an anti-browning agent in foods (Fukusawa et al. 1982). (See: Kojic Acid and Enzymatic Browning)

Nowadays, cosmetic companies are making skin creams using Kojic Acid because it is said to prevent the formation of melanin, or pigment, in skin, resulting in a brighter, more even complexion. Thus some people use creams containing Kojic Acid to treat dark spots on their bodies or face, fade dark freckles or even pregnancy marks.

How does Kojic Acid Work?

Kojic Acid is a tyrosinase enzyme inhibitor that reduces the skin's ability to produce and synthesise melanin. Melanin is what determines the colour pigmentation of the skin. This is why the Kojic Acid can make the area of skin whiter by preventing the synthesis of melanin. Excess melanin comes to the surface and peels off in a few days.

It normally takes 3-6 month of use to see sufficient results, and the darker your skin pigmentation, the longer it's going to take to see results.

Kojic Acid: Any Side Effects?

The Scientific Committee on Consumer Products (the European regulatory body) has conducted extensive studies of Kojic Acid products. Reportedly, they found that Kojic Acid is not a cancer causing agent (unlike hydroquinone).

See:

Opinion on Kojic Acid by the Scientific Committee on Consumer Products
Another study on Kojic Acid: http://monographs.iarc.fr/ENG/Monographs/vol79/mono79-20.pdf

In a review of 165 Kojic Acid toxicity studies, the Nonprofit Environmental Working Group (EWG) notes that some studies have indicated that the substance causes cell mutation in mammals, but that it is not likely to be a human carcinogen. This is why the hazard score of Kojic Acid is low. See: Ingredient: Kojic Acid. EWG.

However, some animal studies have shown high amounts of Kojic Acid to cause liver, kidney, reproductive, cardiovascular, gastrointestinal and respiratory side effects, and high doses have been shown to be toxic to the brain and nervous system in animal studies. According to the EWG, the cosmetics industry has not formed a panel to assess Kojic Acid's safety in humans, and that further research is needed.

Also, after numerous studies people have stated that their skin had become highly sensitive after using Kojic Acid for extended periods of time. Due to these findings manufacturers have now added other ingredients to help counter these effects. Although the amount of Kojic Acid in skincare products is usually not enough to trigger irritation, there is still a danger of developing allergic contact dermatitis with continued regular use.

Be aware that excessive use of Kojic Acid can also result in sun damage to the skin. Melanin protects the skin from harmful UV rays. By reducing the amount in your skin you reduce your natural defence from the sun. It is important to protect your skin from the sun while using Kojic Acid.