Kojic Acid 101: How It Works, How to Use and Best Products

If you like sake, you’ve had kojic acid. Kojic acid is basically a product that is left over after the fermentation process involved in malting rice. In other words, it’s what’s left over after making sake. It is used on cut fruits to prevent them from turning brown, and in seafood to keep its nice, pink color. It also has the added benefit of being able to efficiently lighten skin. At up to one percent kojic acid concentrations, skin lightening products are determined to be safe; it can be found in creams, soaps and serums. Let’s find out all about its benefits, possible side effects, and top products to try.

Our Favorite Products Containing Kojic Acid

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What Is Kojic Acid?

Kojic Acid Powder

Kojic acid is a chemical that is capable of deeply penetrating the skin to stop the production of melanin. This is the pigment that causes age spots and freckles, as well as a deep tan. This acid is sought out as a spot fading treatment because it’s able to more deeply penetrate the skin that most other treatments. The best thing about this acid is that it provides a safer alternative to hydroquinone, which can cause permanent damage to the skin by causing blue stains. In fact, hydroquinone has actually been banned in some countries because it is a possible carcinogen.

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How Does Kojic Acid Work?

Now that’s the $64,000 question. It doesn’t just lighten the skin. It actually prevents your skin from producing melanin in the first place. Melanin is the compound in your skin that causes its pigment. This includes cute freckles and not so cute aging spots – aka, liver spots.

Even healthy skin without these spots will respond to kojic acid, but those who benefit the most are those who suffer from age related skin blemishes and excessive freckles due to sun damage. Basically, when skin is not gently exfoliated, hyper-pigmented skin cells can build up and cause blotchy patches. But when it’s gently exfoliated to reveal the new, healthy skin beneath, you get a lighter, brighter and more even skin tone.

What Is Kojic Acid Used For?

Kojic acid isn’t just used for skin lightening and skin tone evening. As said above, it’s used to preserve the natural colors of freshly cut fruits and meats. But it has other uses in the food industry as well as a natural preservative. It also occurs naturally in soy sauce, miso, and sake.

For skin lightening and skin tone evening, this acid is used in either a cream or a soap form with a concentration of up to 2% to 4%, but usually around 1%. Users of this skin lightening product find comfort in the fact that it is used safely in our food supply, so is therefore perceived to be safer for use on the skin.

before and after using a skin lightening cream with kojic acid

Benefits of Kojic Acid

The benefits of this acid are uncertain at this time, as more conclusive studies are still outstanding. For instance, some studies have found kojic acid to be a cancer curative. Others are not so conclusive. Still, the most well known benefit of this acid is that it helps to fade age spots by stopping skin from producing melanin in the first place. This makes it a much more effective skin lightener than hydroquinone in the long run, but its use must be continued or the dark spots may ultimately come back.

Side Effects of Kojic Acid

You can purchase raw kojic acid, but it’s not even remotely recommended for use on the skin. It is way too corrosive. The main side effect of kojic acid-containing products is allergic contact dermatitis. If using it for a long period of time, it can also cause a bluish tint, as it changes the skin’s color abnormally. Hypersensitivity is another issue and one needs to apply corticosteroid after exfoliation to protect the skin.

Kojic acid MUST be diluted to a concentration of less than 2% to 4% and, preferably, 1% to work effectively without causing severe skin irritation. Therefore, you are likely much better off using kojic acid in the form of a pre-made skin cream or soap that has already been made to specific concentrations that will not irritate skin.

Best Products Containing Kojic Acid

Kojie San Skin Lightening Kojic Acid Soap

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This is definitely one of the most inexpensive ways to work kojic acid into your skin care routine. At only around $8 for three bars, Kojie San is a gentle skin cleansing soap that can be used on all parts of the body up to twice a day to lighten freckles, moles and dark spots. At the same time, it also reducing the appearance of large pores and lightening overall complexion. The soap has the added benefit of reducing acne outbreaks with its exfoliating action, to reveal an overall healthier skin tone.

Reviva Labs Brown Spot Night Cream with Kojic Acid

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At only $7 for a 1oz jar, this is a very affordable skin lightening cream. The product is free of mineral oil and animal ingredients so it’s safe for vegan use. Its soothing ingredients are designed to soak into the skin more thoroughly so users will see faster results. Most people see lighting in their age spots, dark spots and freckles within about four weeks with once daily treatment.

Fade It Serum with Kojic Acid

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Fade It is definitely one of the more expensive skin serums on the market at around $60. Nonetheless, its formulation is well worth it. The gentle 1% kojic acid formula works in conjunction with Punica Granatum Extract and Aloe Babadensis Leaf Extract to help not only lighten skin, but also to provide a more youthful glow and moisturized feel. It also has a little pomegranate extract to add antioxidants. This kojic acid serum can be applied twice a day if users want to see faster results.


Not everyone believes kojic acid to be completely safe for skin. The European Commission’s report in 2008 found kojic acid to be an unsafe skin product based on its actions to block skin pigment. It has also been viewed as unsafe by some scientists based on the fact that it disrupts basic biochemical processes. Some believe that this may make kojic acid a carcinogen; studies show that it causes cancer in mouse thyroid glands. It’s also been found to have anti-cancer effects, so there are no conclusive studies. Therefore, it’s best to discuss the use of this acid with your dermatologist to ensure that the benefits outweigh the risks.

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