Kojic acid: What you need to know before using it

Updated: May 7, 2020

Kojic acid is one of a few skin-lightening ingredients to hit the beauty media spotlight recently. Across the internet, reviews vary from A-M-A-Z-I-N-G results to experiences of irritation, and not seeing any difference at all. Does kojic acid even work for the skin? Some writers discuss the potential risk of using kojic acid and how it can increase the risk of cancer, which has left many of us wondering whether it is worth trying it out or not. How dangerous is kojic acid? This blog post explains the what and why we should be using this ingredient, and the knowledge you must consider, before establishing kojic acid into your skincare routine.

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What is kojic acid?

Kojic acid is a lab-engineered chemical, produced from strains of the Aspergillus fungi. Discovered in 1907, this food preservative is a by-product of food fermentation, from things like Japanese sake, rice wine and soy sauce. The word ‘koji’ directly translates into ‘steamed rice’ in Japanese.

Kojic acid can appear on a ingredients list as:



What does kojic acid do in skincare?

The main role of kojic acid in skincare is that in inhibits tyrosine function, which controls the melanin production in our skin. Melanin determines the colour of our skin, eyes and hair and is found in both humans and animals. Extensive research has proven that excessive UV exposure can lead to an excessive production of melanin, which eventually develops into skin hyperpigmentation, and in worse cases, skin cancer.


Excessive sun exposure leads to hyperpigmentation

In theory, kojic acid is beneficial to anyone who wishes to lighten existing hyperpigmentation (brown spots, sun damage and scarring), and brighten their overall skin tone. It does not ‘get rid of’ pigmentation, but can certainly lighten it to an extent.

Because of this you will see kojic acid present in many cosmetic formulations; from creams and serums, to face masks and cleansers. Kojic acid has quite a low absorption rate in humans and therefore can only really be effective in concentrations of 1% and higher.

Kojic acid also plays an anti-microbial role in the skin, so can help alleviate symptoms of acne and general congestion.

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This brightening ingredient is also anti-fungal, so is equally beneficial to treat certain fungal infections such as athlete’s foot and ringworm.

Kojic acid has been widely used in the medical field for years; often teamed with quercetin, to fight colon and cervical cancer cells.

Most studies agree that within 2 weeks of regular topical use of kojic acid, that will see some improvement.  

Kojic Acid (4)

via aestheticsurge

Is there any risk associated with using kojic acid?

There are quite a few testimonials online that agree how irritating kojic acid can be, so I would not advise to use it if your skin is sensitive or sensitised. Contact dermatitis is a common side effect.

Alike any topical acid, it also makes the skin photosensitive so if you are using kojic acid and not protecting your skin with the right SPF, you have a higher risk of not seeing any result and developing further hyperpigmentation and uneven skin tone, redness and sensitivity. 

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Is your SPF really working for you? Find out here.

One medical study has shown how when kojic acid is applied in high concentrations on mice, it can cause tumours to develop. Due to its low absorption rate in humans, there is a small chance this can happen to us, however like many cosmetic ingredients and supplements on the market today, there simply isn’t enough evidence to know for sure.

Some countries have banned the use of kojic acid in products because of this associated risk.

Where can you find kojic acid?

Mesoestetic Ultimate W+ Whitening Essence

£48 for 30ml at Face the Future


via Face the Future

This potent formula uses kojic acid alongside other skin-brightening ingredients such as niacinamide and alpha-arbutin. The serum not only has a whitening effect on the skin, but plays an antioxidant role – preventing further skin damage. Many of the clients I work with use this, alongside de-pigmenting treatments such as fractional laser, microneedling, skin peels and Cosmelan™. For best results, it can be used AM & PM after cleansing, and followed by the Ultimate W+ Whitening cream in the Mesoestetic range.

Dermaceutic Yellow Cream – Skin tone brightener

£36 for 15ml at Dermacaredirect

Dermaceutic Yellow Cream depigmenting concentrate

via Dermacaredirect

Alongside liquorice extract, bus role and glycolic acid, this lightweight formula regulates the production of melanin quite effectively. According to online reviews, you can see results within just 3-4 weeks of using the product, and it I advised to use for 3 months for optimum results. Except for sensitive skin types, this cream formula can suit many skin types including oil and acne-prone skin, due to the product’s keratolytic acid, salicylic. Apply in the evening, after cleansing the skin.

Neostrata Enlighten Illuminating serum

£38.95 for 30ml at Farmaline

neostrata pigment lightening gel

via swedishface

This impressive serum boasts 12 other active brightener ingredients, including kojic acid. It has a ton of positive reviews online for its lightweight texture, and out-of-this-word results. The pump on the bottle prevents unnecessary product wastage and is affordable in a generously sized 30ml, in comparison to other pharma-grade cosmetic competitors. It is most beneficial to use this gel in the morning after cleansing, and before your SPF. In the evening you can layer this product underneath creamier formulations if you decide you need the added moisture.

Kojic acid is an effective ingredient that can brighten conditions such as melasma, post-inflammatory pigmentation, age spots and can even reduce the production of acne and fight fungal infections. It is important to know that kojic acid can cause irritation to the skin and use should be reduced or postponed completely depending on the severity of the reaction. A physical SPF should be worn and topped up daily in any case of treating pigmentation, and using acid-based products to do so. Always remember to read the label of any product that claims to have a particular ingredient inside. Have you tried, or considered using kojic acid before? Comment below.

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#skincare #mesoesteticWwhiteningessence #skincarescience #skinbrightening #skinlightening #kojicacid

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