What Is Kojic Acid (& How To Use It In Your Skincare Routine)

Although it may seem like a new, need-to-know-about skincare ingredient, kojic acid has been around for quite some time.

It was first developed in 1989 and used in a professional setting to brighten brown spots, hyperpigmentation, and stubborn post-breakout blemishes.

Although it’s still not talked about all too often, kojic acid doesn’t come on its own. Still, it is often an accompanying ingredient in cleansers, serums, and moisturizers to tackle specific pigmentation concerns.

And if you have never heard of it, but the title got you rather curious about trying it out – you came to the right place.

This article explains what is kojic acid and how to use it in your daily skincare regimen.


NB: I can show you how to never have acne again. If you have acne and want it gone, read this message.

What is Kojic Acid?

Kojic acid is a chemical derived from different types of fungi but it can also be created during the sake brewing process from fermented rice or soy sauce. 

what is kojic acid

Kojic acid is sometimes used in the food industry as a naturally derived preservative, but today’s main use of kojic acid is mainly in skincare products.

It is an accompanying ingredient in many soaps, cleansers, serums, toners, and moisturizers and they all have different concentrations of kojic acid.

The products containing kojic acid often come with instructions of use by the manufacturer and this is extremely useful so you can reap the most benefits in an intended way.

While soaps and cleansers have to be washed off immediately after application, toners, serums, and moisturizers are always to be left on the skin for better absorption and best results.

Skincare products containing kojic acid often have a concentration between 1 and 4 percent.

What Does Kojic Acid Do To The Skin?

Kojic acid is able to block tyrosinase, which is the enzyme that forms the brown pigment melanin in the deeper layers of your epidermis.

Tyrosinase works by converting the amino acid tyrosine into melanin.

Because of its ability to penetrate the layers of your skin, kojic acid blocks this process by sitting in the active site of tyrosinase, leaving no space for the amino acid tyrosine.

Kojic acid is usually sought out as a spot-fading or pigmentation and melasma treatment as it is a somewhat less aggressive option to hydroquinone which makes it a better option for sensitive skins.

Because it inhibits melanin production in its core, kojic acid can have a lightning effect on the skin. It is widely used in Asia for skin brightening treatments and a highly effective “luminescing” agent on the market alongside oxyresveratrol.

Oxyresveratrol, on the other hand, occurs in white mulberries, which are native to northern China.

While it is exceptionally good at inhibiting tyrosinase, this ingredient is notoriously difficult to formulate with and can be extremely unstable at higher strengths.

How Long Does It Take For Kojic Acid To Lighten Skin?

how to use kojic acid on the skin

An agent that is exceptionally useful in pigmentation treatments such as kojic acid can begin to work in days, depending on the strength you are using.

However, as with all skincare products, it can take up to a few weeks to see a noticeable and appreciable reduction in unwanted hyperpigmentation or melasma.

Moreover, if you see no difference in four to six weeks, it is likely that the product won’t work for you and that you may require a higher concentration of kojic acid.

The same goes for nearly all skincare products and although it may seem time-consuming and disappointing, this is the best way of knowing if the product is good enough to improve your skin concern.

Can Kojic Acid Remove Acne Scars?

Kojic acid has mild antibacterial and antifungal properties that can show effectiveness against acne-causing bacteria as well as inhibit the overgrowth of yeast on the surface of your skin.

This can prevent unwanted acne breakouts and fungal infections.

However, due to its excellent brightening properties, kojic acid is exceptionally effective in reducing the discoloration that often comes from acne scars.

Although it doesn’t soften the thickness of the scar tissue, it may reduce brown spots, hyperpigmented areas, and even post-inflammatory erythema.

Lightening the scars can make them seem less obvious.

Is Kojic Acid Safe For Dark Skin?

Kojic acid is safe to be used on dark and fair skin tones due to its ability to prevent the abnormal production of the pigment melanin that causes dark spots and darkening in certain areas.

Women with dark skin tones can safely use kojic acid to brighten their complexion and reduce unwanted pigmentation.

However, kojic acid can make your skin photosensitive, so it is always recommendable to be followed up with adequate sun protection in the morning.

Kojic acid inhibits the production of melanin, and melanin is also responsible for protecting your skin from sunburn by giving it a tan.

When melanin production is compromised at its core, your skin becomes susceptible to sunburn and damaging free radicals.

To avoid any side effects, it is always the best practice to protect your skin from the detrimental UV rays.

Does Kojic Acid Have Side Effects?

Kojic acid in low concentrations is relatively safe to be used in cosmetics as a hyperpigmentation treatment.

However, some individuals may still experience side effects from its use. Here are some of them:

Contact Dermatitis

The common side effect of using kojic acid is contact dermatitis, which can manifest itself as redness, irritation, itchiness, rashes, and mild to moderate swelling.

Contact dermatitis is most common in sensitive skin that can become irritated if the product they are using has a higher concentration than 1 percent of kojic acid.


Prolonged use of kojic acid may make your skin more susceptible to sunburn. Always make sure to be diligent in using sunscreen or wearing protective clothing.


Kojic acid should never be used on damaged or broken skin.

It is not designed to heal recent scar tissue and can irritate the damaged area.


Although rare, some people may have an allergic reaction to this ingredient and in this case, they will be strongly advised against using the product.

However, the best way to see whether you may have a reaction to kojic acid is to always do a patch test on the inside of your wrist as an allergic reaction typically manifests within minutes or in the first 24 hours.

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