Kojic Acid is one of those weird-sounding beauty ingredients that you have probably seen but don’t know what it does.
This versatile chemical is actually produced by a mold called Aspergillus Oryzae, also known as “Koji”.
This same mold is used to produce some of your sushi bar favorites including soy sauce and sake, and may have some beauty benefits when applied to the skin.
Kojic Acid is considered an antioxidant in the cosmetic world, but its main effect is generally skin lightening.
Kojic Acid achieves this effect by blocking an enzyme called tyrosinase, which leads to less production of melanin by skin cells.
And since it is the melanin in skin cells that produce skin pigmentation, making less melanin means a lighter appearance.
When using topical Kojic Acid creams, you will likely start seeing the lightening results after 2 weeks of continued use.
If you are using Kojic acid on hyperpigmented (darkened) areas like acne marks that were left from damage to the skin - it is unlikely that the hyperpigmentation will come back unless the area is “damaged” in some way again.
However, if you are trying to lighten your natural skin tone for some reason, once the product is stopped your natural melanin making rate will return and so will your natural skin tone.
If your skin produced extra melanin from damage like sun or acne, the lightening may be “permanent” as long as you protect that area from additional sun and damage.
If your darkened skin areas are your natural skin tone or from a disease state like chronic melasma, the lightening effects will likely wear off over time once the product is stopped.
Pro tip: wearing sunscreen and avoiding the sun will help Kojic Acid-lightened areas last longer.
A 2010 review of the safety of Kojic Acid was conducted after an animal model study showed increased rates of carcinogenicity with high levels of Kojic Acid.
This review concluded that Kojic Acid was safe up to 2% in cosmetic preparations, and should not get into the circulation in high enough amounts to cause these effects.
Since Kojic Acid is reducing the amount of melanin in the applied areas, this may put you at risk to be more sensitive to sunburn.
Another potential side effect is skin irritation or contact dermatitis on the applied areas.
This includes a minor rash, itching, or dryness.
To help avoid these side effects:
Make sure to wear sunscreen daily and stick to the lower strengths of Kojic Acid (2% or less).
You can find Kojic Acid in certain over-the-counter cosmetic products or in prescription compounded creams.
Our Melasma Formula combines pharmaceutical-grade Kojic Acid with other evidence-based chemicals to help reduce the darkened areas characteristic of Melasma.
We included the prescription ingredient Hydroquinone in this physician and pharmacist formulated blend.
One study found the combination of Hydroquinone and Kojic Acid to be the superior combination for depigmentation in melasma patients.
Kojic Acid is a skin lightening agent derived from a mold called Aspergillus Oryzae.
This ingredient may also possess antibacterial and antifungal properties.
You should start seeing the lightening effects of Kojic Acid after 2 weeks of treatment.
A safety review on Kojic Acid deemed concentrations of up to 2% to be safe to apply topically and left on overnight.
Side effects from Kojic Acid applied to the skin include: increased sensitivity to the sun and skin irritation.