Kojic Acid Skin Lightening Soaps and Everything You Need to Know

Among the many products that you will come across while shopping for skin lighteners are skin lightening soaps. To give you a deeper understanding, we have compiled everything you need to know about kojic acid skin lightening soaps.For starters, these are soaps whose active ingredient, kojic acid, is known to inhibit skin melanin production. As a result, you should expect lighter, flawless and youthful skin. In this article, we will focus on how kojic soaps work, the benefits, how to use, and the side effects. We will also throw in some tips on how to get the best results.

What are Kojic Acid skin Lightening Soaps?

Kojic acid soaps, also known as ‘kojic soaps’, are topical skin lighteners whose active ingredient is kojic acid, a byproduct of rice fermentation. Back in 1989, Japanese women were coming into contact with the acid as they made Sake, Japanese rice wine. This lead to the discovery of the organic acid’s skin lightening-properties.[1]   

How They Work

The kojic soaps work by exfoliating the skin’s outermost layer. The process removes the dead skin cells, dirt and excessive oil to give rise to renewed, clean and youthful skin.

Additionally, once the dead skin is removed, the acid can penetrate deeper where it slows down melanin production. Melanin is the pigment responsible for skin colour. When produced in excess, it causes hyperpigmentation. Less melanin, therefore, means lighter skin.

Kojic acid is also an antioxidant. Using it helps in protecting your skin cells from oxidative action from free radicals. At the same time, the acid has antifungal and antibacterial properties which come in handy in combating bacteria that cause acne and other skin issues.

Benefits of Kojic Acid skin lightening Soaps

Dr. Jenniffer Hermann,  Dermatological Surgeon,

Moy Fincher Chipps Dermatology,

Beverly Hills

If you’re looking to brighten your skin and reduce unwanted brown spots, kojic acid is a good option. It’s a great alternative to hydroquinone, which can be too irritating for sensitive skin types.[ 2]

Kojic soaps have made a name for themselves mainly due to their skin lightening properties. In addition to this, more benefits come with using these soaps regularly. Here are some of these benefits:

  • Anti-ageing Effect

With proper use, kojic soaps are good at improving the appearance of wrinkles and age spots. These anti-ageing properties stem from the manufacturers’ incorporation of collagen and elastin. 

These substances are responsible for skin firmness and elasticity. Their levels in the body decline with age, and hence using kojic soaps helps in boosting their synthesis.

  • Reducing Skin Imperfections

Imperfections such as blackheads, whiteheads and dead skin cells cause the skin to appear dull. Kojic acid soaps are excellent exfoliants; hence, their use will significantly remove these skin enemies.

  • Antifungal and Antibacterial protection

The human skin is exposed to the fungus in the environment that leads to various infections. Examples include athlete’s foot and yeast infections. 

The Kojic acid in these soaps is handy in combating these fungal infections. Its antibacterial properties also help to keep away bacterial infection on the skin area of application.[3]

  • Reducing the Effects of Melasma 

Melasma is a condition that causes discolouration and formation of rough and hyperpigmented patches on the skin. Hormones trigger this skin disease which mostly manifests in pregnant women. The condition can also be caused or worsened by exposure to UV rays. The kojic acid in these soaps does well in stripping the darkened and rough skin patches to result in lighter and smoother skin. Compared to common toxic skin lighteners like mercury and hydroquinone, the acid is organic and safer. These facts make it a better option for pregnant women. Sometimes, they come combined with other natural ingredients such as glutathione, papaya extract and saffron to enhance their benefits.

How Long Does it Take to See Results?

Most of these soaps take different times to show the desired results. The outcome is mainly dependent on the acid concentration and the type of additional ingredients infused in the particular soap. That said, it typically takes about 8 weeks before results become noticeable.

Side Effects of Kojic Acid Skin Whitening Soaps

There are several side effects associated with using Kojic acid soaps. These, however, do not run across the board because of skin type differences.[4] Depending on how sensitive your skin is, the side effects can last for up to 3 weeks. They include:

  • Dry skin
  • Mild itchiness
  • Skin breakout especially if you are acne-prone
  • Peeling- a side effect that is indicative of exfoliation
  • Skin tightness 
  • Burning sensation

It’s good to note that with proper use of these soaps, most of these side effects are manageable.

How to Use Kojic Acid Skin Lightening Soaps

Here are the recommended ways to use these skin lightening soaps:

  • Before you start using, apply the soap on a small area of your arm or face and watch out for any adverse reaction- this is a patch test.
  • Always wash your face with warm water before using kojic acid skin lightening soaps to unclog skin pores and allow better acid penetration.
  • During the first week, use the soap once and during application let it stay for not more than 20 secs. With time, your skin gradually gets used to the acid. 
  • Once you feel comfortable with the soap, probably the second week onward, you can let the soap linger longer after application and perhaps use it twice daily for faster results.
  • Always finish washing by rinsing your skin with cold water for at least 2 minutes. This closes your skin pores, making them less visible and giving your skin a smoother feel.   

Additional Tips on Getting Best Results

Best results are dependent on the following tips:

  1. Do not use the products on broken skin
  2. Apply moisturiser to reduce dryness and avoid itchiness
  3. Do not expose skin to sunlight during use; the product causes photosensitivity. If you venture out, use a strong sunscreen and protective clothing.
  4. Follow the manufacturer’s label on usage or as recommended by your aesthetician

The Cost of Kojic Soaps

The cost of kojic soap is dependent on factors such as net weight, the brand, packaging, and existing offers. With these differences, not two brands cost the same. It will be upon you to shop for one that gives you the best offer and value for your money.

Heidi A. Waldorf, MD

Waldorf Dermatology and Aesthetics, New York

In my experience, the acid is often irritating —particularly in conjunction with other lightening ingredients like retinoids, alpha hydroxy acids and vitamin C. I recommend starting it gradually.[5]


Kojic soap is one of the most common skin lightening soaps in the market. It works by exfoliating the dead and darkened skin, and reducing the production of melanin. Its active ingredient is kojic acid. Apart from skin lightening abilities, kojic soaps come with additional properties that work together to make your skin look younger and smoother. These properties, coupled with the fact that kojic acid is organic, have made the soaps popular among many compared to other skin lightening soaps which may contain hydroquinone and/or mercury. If you decide to try out kojic soap, the above information gives you a place to start.


sonia knight

Sonia Knight is the founder of be:skinformed.

Apart from having her own experience with hyperpigmentation, Sonia has gained vast knowledge in the dermatology field. For more info on this, check out our about us page.


1 R&D Report: Kojic Acid, Dermed Technology

2 This Kojic Acid Serum Will Brighten up Your Dull Skin, Mydomaine

3 Kojic acid: What you need to know, Medical News Today

4 Kojic Acid Side Effects, Healthline

5 Is Kojic Acid Safe? New Beauty

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