POSTED: 28 Oct 2023

Here’s What Kojic Acid Can Do For Your Skin

Its hard to make an impact in the jam-packed world of skincare, so it takes something special to consistently make an impression. Kojic acid is one beauty ingredient that manages to stand out in a crowded field. It gets wide praise from beauty enthusiasts and dermatologists alike. However is this skin brightening agent the game changer everyone makes out? In this article, we review what exactly is Kojic acid and how does it compare with other hyperpigmentation treatments like hydroquinone. We’ll take a deep dive into the science behind Kojic acid, benefits, risks and how to use it.

What is Kojic Acid?

Kojic Acid is a naturally occurring substance derived from a type of fungi called the Aspergillus oryzae species, known as Koji in Japanese. This fungus ferments rice to make sake, the Japanese rice wine. Kojic acid was first isolated in 1907 by Japanese scientists during the sake fermentation process. However, discovery of its skin-lightening benefits wasn’t until several decades later. This marked the beginning of its use in the beauty industry.

The discovery of Kojic Acid’s ability to inhibit melanin production, responsible for skin pigmentation, sparked interest in it as an alternative to other skin-lightening agents like hydroquinone. Even better was the prospect that it could have fewer severe side effects. By the late 1980s and 1990s, Kojic Acid had started gaining popularity in cosmetic formulations. At this point, it became more accessible in a variety of skin products including creams, lotions, serums and soaps. All of these were developed and sold as a treatment for hyperpigmentation, age spots and sun damage.

Whilst it originated in Japan, the popularity of Kojic acid quickly spread to other parts of Asia and eventually Western countries. Its effectiveness in treating hyperpigmentation made it a sought-after ingredient in the global beauty and skincare industry. Over the years, there has been continuous research and development to improve the stability and efficacy of Kojic Acid in skincare products. This has lead to various derivatives and formulations. It has also made it much more affordable and widely available.

How Does it Work & When Can I see results?

At the heart of Kojic acid’s mechanism of action is its ability to interfere with the production of melanin. It does this by inhibiting a key enzyme called tyrosinase, which is necessary for melanin synthesis. By blocking this enzyme, Kojic acid effectively reduces the production of melanin, leading to lighter skin and a more even skin tone over time. This process takes place in the skin cells known as melanocytes. Kojic acid also has antioxidant and anti-inflammatory properties. This means it can help fight against skin damage caused by free radicals, which can contribute to skin aging and pigmentation issues. As it is a relatively small molecularly, this means it can easily penetrate the upper layers of the skin where it can act on the melanocytes.

Results vary from person to person. They depend on your skin type, sensitivity and severity of your hyperpigmentation. However, you might notice improvement in as little as 4-6 weeks of consistent use. That being said, it may take several months to see the maximum benefits.

Benefits of Kojic Acid

The main benefits of Kojic acid are that it reduces hyperpigmentation, brightens and evens skin tone. This makes it a popular ingredient for those seeking to treat dark patches, age spots, melasma and other forms of hyperpigmentation. However, it does have a number of uses:

  • Skin Brightening & Hyperpigmentation: No doubt, this is it’s key benefit. It reduces melanin production and as such helps lighten dark spots and patches to even out skin tone.
  • Anti-Aging: This indirect benefit is due to Kojic acid evening out skin tone by treating sun and age spots. This helps give the skin a more youthful appearance.
  • Antioxidant: Kojic acid helps to fight free radicals and prevent oxidative stress to counteract environmental damage to the skin. These factors normally contribute to skin aging.
  • Antimicrobial: Another benefit of Kojic acid is that it has antifungal properties which means it can help treat certain fungal infections, such as yeast infections and athlete’s foot. It also exhibits some antibacterial properties, making it helpful for addressing acne.
  • Fading Scars: Although it won’t eliminate scars, kojic acid can lighten them and thus make them less noticeable.
  • Enhancing Other Treatments: You can use it alongside other skin-lightening agents like hydroquinone, glycolic acid and retinoids. This enhances their effects and it can also help with maintaining results.

Products Containing Kojic Acid

Kojic acid is available in a wide variety of skincare products. These vary in the way you can use them and some are better for certain skin types than others. Here are some common ones and when they might be best to use:

Soaps & Cleansers

These are popular and ideal for those looking for an easy and quick way to incorporate Kojic acid into their routine. Soaps are best for individuals with oily or acne-prone skin, as they can help reduce oiliness. However, soaps may be too drying for those with dry or sensitive skin. You use them like regular soap, but leave the lather on the skin for a few minutes before rinsing.

Cleansers are suitable for daily use and are best for individuals who prefer a gentle introduction of Kojic acid into their skincare routine. Massage the cleanser on your face in circular motions and rinse off. Be aware that frequent use might cause dryness in some skin types. Cleansers are suitable for all skin types, but especially for oily or combination skin. However, they might not be the best option for very dry skin or those with severe hyperpigmentation.


It is best to use these after cleansing. Soak a cotton pad and swipe it across your face, avoiding the eye area. These are good for combination to oily skin types, as toners can help control oil. However, Kojic acid toners might not be suitable for those with dry skin.


Kojic acid serums are more concentrated and are ideal for targeted treatment of dark spots or hyperpigmentation. Apply a few drops on cleansed skin and gently pat in. These are great for all skin types, but especially for those who prefer a lightweight formula. Serums are not ideal for highly sensitive skin due to the high concentration of active ingredients.

Creams and Lotions

These are suitable for daily use and can work for all skin types. However, they are particularly beneficial for those with dry or normal skin. Apply a small amount to the whole face for overall skin brightening or as a spot treatment and massage gently. You will still need to follow with a moisturiser especially if you have dry skin.


Kojic acid masks are best for those looking for a deeper and more intensive add on treatment. Apply the mask as per the instructions, usually once a week, and leave it on for the recommended time before rinsing. Masks are good for most skin types, but not if you have extremely sensitive skin. People with dry skin should look for masks that also offer hydrating properties.

Tips for Using Kojic Acid in Your Skincare Routine

Before adding Kojic acid to your routine, start by figuring out your skin concerns and goals. Also choose a product takes into account your skin type and sensitivity. Below are tips that will help make this process easier:

  • Patch Test: Always do a patch test to check for any allergic reactions before full application.
  • Sun Protection: Use sunscreen daily as kojic acid can make your skin more sensitive to the sun.
  • Moisturise: Kojic acid can be drying so pair it with a good moisturiser to keep your skin hydrated.
  • Sensible Use: Don’t use multiple Kojic acid products at the same time and be more cautious if you are using other actives in your routine. Always start with a low frequency and strength. This will help you avoid skin irritation.
  • Follow Instructions: Adhere to the usage instructions provided with the product.
  • Be Patient: It takes time and consistent use to see benefits from Kojic acid.
  • Seek Expert Help: Consult with a dermatologist before starting new skincare products if you have sensitive skin or a skin condition. This is also a good idea if you are using prescription skincare treatments.

Who Should Avoid Kojic Acid

Although Kojic Acid is safe for most, certain individuals should be cautious. This includes people with sensitive skin or conditions like eczema or rosacea. These groups may find Kojic acid too harsh and so should avoid it or use it with caution. Additionally, if you are pregnant or breastfeeding, consult your doctor before using Kojic acid or any other active skincare products. Lastly, absolutely avoid using Kojic acid on broken or sunburnt skin.

Side Effects & Long Term Considerations

In general Kojic acid is a safe and widely tolerates skincare ingredient. However, nothing is risk free and there are key side effects you should be aware of:

  • Skin Irritation: It can cause redness, irritation or contact dermatitis. Reduce the risk of these by starting with a low strength and frequency as well as a product suited to your skin. Always start with a patch test and take into consideration your skin type, sensitivity and conditons.
  • Sun Sensitivity: This increases susceptibility to sun damage. As such always use strict sun protection including a broad spectrum sunscreen with at least SPF 30.
  • Limit on Duration of Use: As with any pigment suppressor, it is best not to use Kojic acid continuously for extended periods. This will avoid the risk of skin bleaching and rebound hyperpigmentation.
  • Maintenance of Results: Upon stopping Kojic acid, the skin may gradually return to its original state. It’s important to maintain a skincare routine that includes sun protection, antioxidants like Vitamin C and retinoids to sustain results.

How Kojic Acid Compares With Other Skin Brightening Agents

Kojic acid is often compared to other popular and more established skin brightening ingredients in skincare. These include hydroquinone, arbutin, retinoids and vitamin C. Below we compare and contrast Kojic acid with each of these for treating hyperpigmentation.


This is the big beast when it comes to treating hyperpigmentation. Like Kojic acid, hydroquinone also suppresses the enzyme that is needed for pigment production. However, hydroquinone is more potent than Kojic acid and as such is a prescription only medicine in the UK. It also comes with higher risks, including irritation and potential irreversible skin darkening (ochronosis).


In general, arbutin is an obvious competitor to Kojic acid in terms of benefits. Both are available over the counter and inhibit melanin production. However, Kojic acid is considered more potent and is thus a preferred choice for more stubborn hyperpigmentation. Arbutin is often better tolerated by sensitive skin. Additionally, Kojic acid is also less stable and degrade in light and air. It is however available in a wider variety of products than arbutin.


Both Kojic acid and retinoids, particularly Tretinoin are widely used to treat hyperpigmentation. However they work in different ways. Retinoids work by accelerating cellular turnover. This effectively sheds the top layers of skin where hyperpigmentation resides. In addition, prescription retinoids like Tretinoin promote overall skin renewal and collagen production. This helps treat hyperpigmentation, skin ageing, scars and acne. Kojic acid on the other hand has fewer benefits and is limited to treating milder forms of hyperpigmentation. However, retinoids are associated with a higher likelihood of irritation and Tretinoin is available by prescription only. The good news is that you don’t have to choose! You can use both of these together to enhance your results.

Vitamin C

This is a strong antioxidant and another skin brightening agent. It does not directly suppress pigment production and as such is less potent as a lightener compared to Kojic acid. Vitamin C can also boost collagen and overall skin health. As such, Vitamin C is better used in combination with Kojic acid to brighten the skin and fade hyperpigmentation.

Glycolic Acid

Another skincare product that’s often compared with Kojic acid is glycolic acid. However, they have different primary functions. Glycolic acid is an exfoliant and evens out skin tone through removing the superficial damaged layers of skin. It is not a substitute for Kojic acid but they can be used together for to enhance each other’s effects on hyperpigmentation.

Azelaic Acid

Both azelaic acid and Kojic acid are effective treatments for mild hyperpigmentation. Azelaic acid also has anti-inflammatory properties and so is also more commonly used to treat acne and rosacea. It is often better tolerated by those with dry or sensitive skin than Kojic acid.


Lastly, niacinamide is also a gentle skin brightening agent. It works by inhibiting the transfer of melanin to skin cells, which is different from the direct inhibition of melanin production by Kojic acid. Niacinamide is less potent than Kojic acid for treating hyperpigmentation. However, niacinamide is a powerhouse skincare ingredient that also strengthens the skin barrier, regulating oil production and shrinks pores.

Kojic Acid is generally a safe and effective treatment if you want to treat hyperpigmentation or brighten your skin, It is widely available and versatile which makes it a popular choice in the skincare world. However, as with all skincare treatments, individual results may vary and a lot of patience is needed. Like with anything in life there are limitations to what it can achieve and risks if it is not used correctly. There are also a number of alternatives that also treat hyperpigmentation and brighten the akin. As such, before rushing to add anything to your routine, consider what is best for your skin concerns, goals and skin type. Consul with a dermatologist or skin specialist if you have stubborn hyperpigmentation, skin conditions or other medical problems to see if Kojic acid or something else will work best for you.

At City Skin clinic, we are devoted to personalised skincare and holistic treatments. Through our virtual skin clinic, we connect clients with our doctors for safe and effective treatments like Tretinoin and Hydroquinone. We treat skin conditions like acnehyperpigmentationmelasma and skin ageing. To start your personalised skincare protocol, book a virtual video consultation or use our online consultation form. The journey towards great skin starts here.

Authored by:

Dr Amel Ibrahim
Aesthetic Doctor & Medical Director
Founder City Skin Clinic
Member of the Royal College of Surgeons of England
Associate Member of British Association of Body Sculpting GMC Registered - 7049611

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