If you follow beauty accounts on TikTok or Instagram Reels you may have seen a small bar of orange soap show up in your feed recently. These orange soaps are bright in colour and promise to brighten your skin. They contain kojic acid and are the newest beauty trend to take the internet and the beauty world by storm.
But this popular soap isn’t as great as people say it is. Scientists at the Good Housekeeping Institute Beauty, Health, and Sustainability Lab say that this popular skincare trend doesn’t live up to the hype. It’s not clear if kojic acid soap can really make your skin brighter, though. Before you swear off using kojic acid in your skin care routine forever, our experts say that it can make your skin look brighter. However, we do not recommend using the soap.
Read on to find out more about this strange ingredient and what you should use instead of kojic acid soap to make your skin look brighter.
What is the acid called kojic?
First of all, what is kojic acid? And why do people want it in soap? Kojic acid is a skin-lightening chemical that is used in cosmetics. Kojic acid, like many other skincare ingredients, can be found in nature or made in a lab. “Several types of fungi, especially Aspergillus oryzae, make koji acid on their own. However, this organic compound can also be made by either biological fermentation of carbohydrates or chemical synthesis,” says Sabina Wizemann, Director of the Beauty Lab at the GH Institute.
How does kojic acid make skin brighter?
Scientific studies demonstrate that kojic acid is a component that inhibits tyrosinase, an enzyme integral to melanogenesis. Kojic acid lowers the amount of melanin made, which has both good and bad effects. Wizemann says that cutting down on melanin production can help even out skin tone, get rid of dark spots, lessen hyperpigmentation, and lessen melasma. Sadly, there is no rose without a thorn. Keep in mind that Kojic Acid can make your skin more sensitive to UV rays when you use it (more on the risks below).
Kojic acid can do more than just brighten skin; it can also protect it from free radicals and bacteria. One study found that kojic acid can help stop bacteria from growing and acne, while another found that antioxidants can protect the skin from damage caused by free radicals like smog and dust.
This is why we don’t think you should buy kojic acid soap.
You might be thinking, “Those benefits sound great!” Why not use a bar of soap every day to put it on my skin? Don’t worry, I had the same questions. But the Beauty Lab experts all agreed on one thing: kojic acid soaps probably won’t make your skin any brighter. Here are the main reasons our scientists say this popular skincare trend isn’t worth your time:
You wash the ingredient off your skin.
When you lather on soap, it comes off right away, unlike serums and creams. Wizemann says, “Soaps are rinse-off products, so the contact time is too short for proper penetration of kojic acid, which can block the tyrosinase enzyme and stop melanin production.” This means that none of the kojic acid that is lathered onto your skin is being absorbed, so it can’t do its job right.
You can’t apply soap exactly.
One more problem with soaps is that you have to use them all over your body or face, and you can’t focus on certain areas to get the benefits directly through the skin. This is a problem with kojic acid in particular because it dissolves quickly in water. Wizemann says that this can make it harder for things to get deep inside, and that “it is unstable when exposed to air or light or higher pH, like in soaps that are usually more alkaline than serums and creams.”
Wizemann says that in order to get the most out of kojic acid, you need to make sure you are using the right formulation. She says that “an appropriate environment (like low pH), a combination with other ingredients that help it penetrate, and the right amount of time in contact with the skin” are all necessary for it to be helpful. Kojic acid is one of the many ingredients in soap, but it doesn’t create the right environment or allow for precise application that will get into the skin.
Also, not everyone can use kojic acid.
The Cosmetic Ingredient Review found that kojic acid is safe to use in leave-on cosmetics at concentrations of up to 1%. However, people with sensitive skin may have some negative effects when using any product with kojic acid. For some people, washing their skin with kojic acid soap every day (or even twice a day) might be too drying or irritating. Wizemann says, “Depending on how concentrated it is and how long it is used, it may cause redness, tightening, dryness, and irritation, especially in people with sensitive skin or those who are prone to eczema.”
Kojic acid can make skin more sensitive to UV rays, even if you don’t have sensitive skin. This can make you more likely to get sunburnt, so you need to be extra careful to put on sunscreen with at least SPF 30 every day on skin that is exposed.
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What are the benefits of using kojic acid soap?
If kojic acid soap doesn’t really work to lighten your skin, then why are there so many posts on social media saying it will? And is it bad for everyone to be following this skincare trend?
We don’t know why one trend became more popular than another, but remember that some formulas can still be good for your skin. The kojic acid itself isn’t the main ingredient that gives those benefits, though. Wizemann says, “It’s important to remember that all products have more than one ingredient, and the way those ingredients work together is what makes a product work and be good for you.”
Most soaps that are sold as “kojic acid soaps” also have cleaning and exfoliating agents in them. According to Wizemann, these ingredients can be good for bigger areas like the back and chest because they help get rid of dead skin, reduce acne, make skin smoother, and lessen dark spots. So, over time, the soap might make your skin look a little brighter, but that’s not because of the kojic acid, and it won’t work as well as some serums or creams.
So, even though we don’t think you should rush out and buy a bar of kojic acid soap, it’s not harmful to try one or keep using one you already bought. Before you buy it, make sure the Food and Drug Administration (FDA) has approved it. You can find out if a product is FDA-approved by looking it up in the Drugs@FDA database or looking in the FDA “Orange Book,” which lists both brand-name and generic drugs that have been approved by the FDA.
Instead, we suggest using this to make your skin look brighter:
We don’t love the trend of using kojic acid soap, but we do think that this ingredient (and others) in serums and creams can be a great addition to your skincare routine. Wizemann says that “Kojic acid is often found in serums and creams with other brightening actives like niacinamide, vitamin C, and arbutin.” Instead of jumping on the kojic acid soap bandwagon, our Beauty Lab scientists suggest using it in your skin care routine through serums, peels, and creams.
Our chemists suggest using vitamin C serums and products with niacinamide, a form of vitamin B3 that helps brighten and even out skin tone, if you want more brightening skincare or dark spot corrector products that don’t have kojic acid in them.
Even with these tried-and-true products, you won’t see results right away. Wizemann says that short-term effects, like mild brightening, may take one to two weeks to show up, while more significant, noticeable changes may take four to twelve weeks.
You can read our expert-approved skincare ingredient dictionary to learn more about all the different ingredients, their benefits, and how to use them.
Why should you believe Good Housekeeping?
The scientists at the Good Housekeeping Institute Beauty Lab try out all kinds of skin care products, like cleansers, creams, serums, and more. For more than 12 years, Sabina Wizemann has been the Beauty Lab Director and cosmetic chemist at the GH Institute. She has done and overseen tests of beauty products. Before coming to GH, she worked as a chemist in the pharmaceutical and personal care industries for more than 16 years.
Isabella Cavallo, the Assistant Commerce Editor, wrote this article. She has been writing reviews of skin care products and articles about health for many years. To write this story, she talked to Wizemann and looked up scientific studies.
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