Considering adding kojic acid to your skincare routine? Before you do, here’s what you need to know about its benefits, potential side effects, and whether it’s suitable for your skin type.
When it comes to skincare, while some active ingredients like hyaluronic acid, vitamin C, and retinol have been essential for decades, others are starting to make a name for themselves and are increasingly used by cosmetic brands.
Among them, acids stand out in particular: it must be said that their multiple properties for the skin make them unique active ingredients. Zoom in on kojic acid with the insight of Stéphanie Soulé, Doctor of Life and Health Sciences at Typology.
Kojic acid, an active ingredient with multiple benefits
“Kojic acid is a natural derivative of the fermentation of various fungi, but also a by-product of the fermentation of certain Asian foods, for example soybean paste, rice malting for sake making, etc.,” says Stéphanie Soulé. “It is often cited as a more natural and less aggressive alternative to hydroquinone, a depigmenting agent banned in several countries.”
The active ingredient’s brightening properties have indeed made it famous: capable of inhibiting the activation of tyrosinase (the enzyme involved in the formation of melanin, which gives its brown color to the skin and hair) by UV rays, kojic acid can thus reduce the appearance of dark spots due to an excess of melanin (melasma, sunspots, age spots, or post-inflammatory hyperpigmentation related to acne) and helps to even out the complexion.
Furthermore, “kojic acid has moderate antibacterial and antifungal properties, thanks to its ability to inhibit certain bacteria and fungal species, which would allow it to prevent blemishes,” adds the expert.
It also has antioxidant activity, which contributes to its depigmenting effect (because free radicals can induce the production of melanin), and anti-inflammatory properties, which can help reduce inflammation and relieve itching and redness. Good to know: “The active ingredient does not offer rapid results: according to scientific articles published in 2022, it takes at least 3 months or more of regular use of a product with kojic acid to obtain the desired results,” warns Stéphanie Soulé.
For the moment, kojic acid is not an active ingredient that is found in a large number of facial skincare products available in France. If, however, you are considering introducing a product containing it into your skincare routine, Stéphanie Soulé recommends ensuring that the concentration of the active ingredient in the formula does not exceed 1% (beyond that and used in a prolonged manner, it can be irritating, especially for sensitive skin), and to perform a skin test in the crook of the elbow, behind the ear, or on the inside of the wrist to ensure the absence of reaction to the active ingredient.
Subsequently, she suggests introducing it gradually, once or twice a week, before moving on to daily use if it is well tolerated, preferably in the evening. If you suffer from a skin condition or allergies, it is advisable to consult a healthcare professional before starting the use of a product with kojic acid.
Kojic acid: precautions and contraindications to know
While kojic acid is considered safe and well-tolerated by all skin types, our expert believes it is not the best indication for sensitive skin, as “it poses a risk of contact dermatitis in some people,” which is characterized by general discomfort, redness, irritated or itchy skin, and rashes. Stéphanie Soulé emphasizes that it should not be used on skin that is already irritated or damaged.
Furthermore, “another possible side effect of kojic acid is increased sensitivity to the sun’s UV rays: since melanin helps protect the skin from damage caused by the sun’s rays and kojic acid prevents its synthesis, the skin becomes more vulnerable to sunburn with repeated applications.” This is why, as soon as it is introduced into your routine, it is absolutely necessary to apply sunscreen with a high protection factor (at least SPF 30) daily and to wear protective clothing (hat, long sleeves, etc.). This recommendation is quite logical from the perspective of eliminating pigment spots.
This article was originally published by Maïlys Cusset on the Marie Claire France website
