Kojic acid is a chemical produced from different types of fungi. It is also a by-product of fermented soy sauce and rice wine.
Kojic acid is sometimes used in the food industry as a natural preservative. One of the main uses of kojic acid, however, is in some health and cosmetic products.
In this article, we look at how kojic acid is used, what possible health benefits it might have, and what the potential risks and side effects are.
Kojic acid is sometimes used in health and beauty products to lighten the skin. It may be used to treat skin conditions, such as sun damage, scars, and age spots.
The science behind how kojic acid works as a lightening agent involves its effect on melanin production.
Melanin is a naturally occurring pigment in the body that gives the eyes, hair, and skin their color. An amino acid called tyrosine is needed to support the production of melanin.
Kojic acid works by blocking tyrosine from forming, which then prevents melanin production. Decreased melanin production may have a lightening effect on the skin.
Kojic acid is most commonly used in cosmetic products, such as creams, lotions, and serums. It is also used in some soaps. Many products with kojic acid are intended for use on the hands or face.
Products containing kojic acid can also be used on other parts of the body, such as the legs and arms. The concentration of kojic acid in cosmetics is often between 1 and 4 percent.
Certain products containing kojic acid, such as serums, are meant to be applied to the skin and left on and absorbed. Some products, such as soaps, are applied and washed off.
The benefits of using products containing kojic acid may include the following:
- Anti-aging effect: Products containing kojic acid may lighten the skin, which can improve the appearance of age spots and sun damage. The reduction of dark spots can have an anti-aging effect.
- Treat melasma: Kojic acid may also be helpful in decreasing melasma, which is darkening of the skin due to pregnancy.
- Decrease the appearance of scars: Kojic acid may also reduce the discoloration of scars. Although the acid does not improve the thickness of scar tissue, it may reduce dark pigmentation associated with certain types of scars. Lightening the scar may make it less noticeable.
- Antifungal benefits: Kojic acid is also thought to have some antifungal benefits. It may be helpful in preventing and treating certain fungal infections, such as athlete's foot and yeast infections.
- Antibacterial effects: Kojic acid may also provide antibacterial benefits. It may help decrease the chances of developing common types of bacterial skin infections.
Before using products containing kojic acid, it is important to make sure they are safe.
Cosmetic products are not regulated the same way medicines and foods are. Cosmetic products are not required by law to be approved by the United States Food and Drug Administration (FDA) before being sold.
The FDA do have a voluntary registration program for cosmetic manufacturers in which companies can report how their products are made. Also, the Cosmetic Ingredient Review (CIR) Expert Panel reviews safety.
However, this link was weak since kojic acid is slowly absorbed into the circulation. It is unlikely that levels would become high enough to cause cancer in humans.
According to the reviewers, the available data suggest that the use of products containing kojic acid with a concentration of 2 percent for products left on the skin is considered safe.
The CIR Expert Panel agreed that kojic acid could be safely used in cosmetic products.
Raw kojic acid is available, but it is not recommended for skin use. Kojic acid should be diluted to concentrations of no more than 4 percent. A concentration of 1 to 2 percent is recommended to reduce the chance of skin irritation.
Trying to add raw kojic acid to creams or lotions may be difficult and result in levels that are irritating to the skin. Using pre-made skin lotions and creams that already contain kojic acid in specific concentrations may be a better option.
Although the use of products containing kojic acid may be considered safe for most people, there are some risks and possible side effects.
Side effects may include:
Skin may sunburn easily
Using kojic acid may make someone more likely to develop a sunburn. Melanin helps protect the skin from sun damage due to UV rays.
Since kojic acid prevents melanin production, it leaves the skin more vulnerable to sunburn.
Kojic acid can lead to contact dermatitis in some people, especially those with sensitive skin.
Contact dermatitis can cause a rash, itching, and dry patches of skin. In severe cases, pain and blisters can develop.
The concentration of kojic acid in creams, serums, and soaps may vary by manufacturer. Products with a higher concentration of kojic acid may be more likely to lead to irritation.
Kojic acid may be helpful for people who have dark spots on their skin due to sun damage, aging, or scars. Some people with certain skin conditions or allergies may be advised not to use kojic acid, however.
It is always best to talk to a dermatologist to make sure using products containing kojic acid is safe.
A dermatologist can also provide recommendations on specific products, including the frequency of use and the concentration strength.
Some people may see results after a few weeks, although it may take longer in certain situations. Products containing kojic acid may only be recommended to be used for a brief time.
When choosing products, people should be sure to follow their directions for use. It is also important to make sure the product contains the concentration of kojic acid recommended by a dermatologist.
People who develop a rash or irritation when using products containing kojic acid should stop using them immediately. If symptoms do not clear up in a few days, it is best to see a doctor.
People should not use kojic acid on skin that is already red or irritated. It should also not be used on broken skin.