First being marketed within the skincare industry in 1955,1 Kojic Acid (KA) is an FDA-approved common skin-brightening ingredient that has recently resurged in popularity in the last few years — ever since the removal of hydroquinone.2 It is derived from only natural substances, and was discovered through the fermentation of rice wine in 1907; it is proven to assist with the preservation and restoration of natural pigment in fruits, vegetables, and humans.3 .
Kojic Acid is a fungal metabolite found within mushroom spores used for the fermentation of multiple kinds of food (such as sake and soybean paste)4 which works by inhibiting tyrosinase — one of the enzymes which is responsible for stimulating melanin production in melanocytes (the skin cells containing pigment).5
Although melanin is an important factor in UV radiation protection and is what determines the color of skin, hair, and eyes, the overproduction of melanocytes from a variety of factors (such as: sunlight exposure, aging, pregnancy, hormonal fluctuations, acne, and even medications)1 can lead to issues such as melasma, hyperpigmentation, and other pigment-related skin disorders.5
Melanin is produced within the innermost layers of the epidermis, where the tyrosinase enzyme bonds to copper ions to begin a process called melanogenesis (the production of melanocytes).6 In order to prevent melanin production that exceeds a healthy amount, Kojic Acid works by serving as a primary inhibitor for tyrosinase and stops melanocyte creation before it starts by capturing the copper ions and bonding itself to them.1 By using this method, Kojic Acid is able to slow the production of melanin with incredible efficacy — allowing the skin to naturally brighten and correct itself to a more-even tone.
Kojic Acid is clinically proven to treat a wide-variety of skin-pigment disorders,1,7 which can result in abnormal or uneven skin tones, such as:
Other benefits of Kojic Acid:
A general worry for consumers within the cosmetics industry is that any new treatments can result in a worsening of conditions like acne. Conversely to that belief, studies have proven that combining Kojic Acid with other standard acne treatments can actually cause increased effectiveness in the reduction and prevention of acne and its resultant issues (like post-inflammatory hyperpigmentation).10
It is actually proven to be important that Kojic Acid is involved as early as possible in acne treatments in order to help prevent scarring or excessive hyperpigmentation before it begins.11 The use of Kojic Acid will supplement any currently existing routines for those who are acne-prone
Kojic Acid has been observed on a cellular level to suppress hyperpigmentation in melanocytes within only a few minutes after application.7 However, visible results of the treatment have been observed to take anywhere from 8-35 days depending on the extent of the skin issue, but continued and regular use will help to observe and prolong the brightening effect.12
The main side-effect of Kojic Acid use on the skin is called contact dermatitis, and, while rare, it is most commonly seen on patients with sensitive skin. It can result in skin irritation, rashes, inflammation, and itchiness,1 but in the low concentrations used in skin-brighteners it has proven to have a minimal/no effect — especially when combined with other ingredients that help to soothe any form of inflammation.9
Kojic Acid is one of the most extensively studied ingredients for skin-lightening within the cosmetics industry.6 The Cosmetic Ingredient Review (CIR) Expert Panel has done thorough investigations into its toxicity through short-term, long-term, and genetic studies, and concluded that it showed absolutely no toxic properties.9 The FDA regularly reviews the ingredients being distributed within skin-brighteners and ensures that they are suitable for use by average consumers.2
Hydroquinone was the industry-standard for skin-brightening until the last few years, because of its powerful effect on hyperpigmentation; however, within the last few years it was proven to cause permanent damage to melanocytes, and thus irreversibly remove UV protection from the skin.5 This new discovery caused most major countries (including Canada as of August 2018)13 to ban it from all over-the-counter cosmetics. Conversely, Kojic Acid has been proven to provide similarly powerful results to hydroquinone and without the negative side-effects.8