Kojic acid applications in cosmetic and pharmaceutical preparations

Kojic acid (5-hydroxy-2-hydroxymethyl-4H-pyran-4-one)is an organic acid derived from the fermentation of fungi of diverse genus such as Aspergillus and Penicillium,1 and it was first isolated in 1907.2.Its most common use is as a skin depigmenting agent, attributed mainly to the inhibition of tyrosinase, which is the key enzyme in melanin synthesis.Leucocyte modulation, copper-chelating action and free radical scavenging are also involved in kojic acid depigmenting mechanism. Besides that, antioxidant, antibacterial and anti-inflammatory activities were also reported.4 There have been reports of antimicrobial and toxicity studies since the forties,2 but mechanisms of action have not yet been fully elucidated.

Uses

Kojic acid has been used in the cosmetic, pharmaceutical, and food industries:

Cosmetics: Some cosmetic products use 0.4-4% kojic acid as a skin-lightening agent and to increase their shelf life.43 Kojic acid products are among the most expensive skin-lighteners, costing more per ounce than vitamin C and retinol products.

Dental care products: Kojic acid can be used in dental products, like tooth-whitening patches.

Medical: Kojic acid can help treat melasma, a condition that causes hyperpigmentation in the skin. Other medications, such as antimicrobial drugs, also contain kojic acid.

Foods: Kojic acid has antioxidant properties. It is used as a food additive to preserve fresh vegetables, seafood, oils, flour, and syrup.

How To Use Kojic Acid

Kojic acid is mainly found in creams, serums, lotions, soaps, eye creams, sunscreens, and face washes at 0.4-4% concentrations. You can incorporate kojic acid products into your skincare routine to improve dark spots.

Here are a few tips on how to use kojic acid products:

Use products with a maximum of 1% kojic acid: It is safer to use products with a maximum of 1% kojic acid unless your dermatologist advises otherwise.

Try on a small area: Apply the product to a small patch of skin and monitor for a few days for any skin reactions. If your skin starts to itch or burn or a rash forms, stop using it, check what you're using, and consult a dermatologist. Some products can cause irritation when used for longer.

Always use sunscreen: Kojic acid and other skin-lightening agents can increase sun sensitivity. Sunscreen will help protect your skin from potential irritation and sun damage.

Avoid using it on broken skin: Kojic acid is intended for topical use. If you have broken skin, wait until your skin has recovered before using kojic acid.

CONCLUSION AND PERSPECTIVES

In conclusion, kojic acid and its derivatives present a variety of applications for human use in cosmetics, pharmaceutics and medical area, besides being already widely used and known as a skin depigmenting agent. Such activity is due to the molecules binding in tyrosinase active site, regulating melanogenesis factors, leucocytes modulation and free radical scavenging activity. Besides that, kojic acid and its derivatives can act as antioxidant substances, which allow them to be applied as anti-ageing agents. Furthermore, the antibacterial, antifungal and anti-inflammatory actions are extensively described. The potential as antitumor substances might be considered, because of the cytotoxicity results observed in cancerous cell lines, with apoptotic and non-apoptotic pathways activated, without causing damage to normal cells. Other activities include anti-senescence of corneal cells, radioprotection, anticonvulsant, iron chelating and obesity management. The use of derivatives and nanocarriers brings advantages regarding molecule stabilization and activity enhancement. Kojic acid and its derivatives seem to be safe molecules for human use, either through oral or topical route, considering the in vitro and in vivo studies reported. Further researches about the topic, especially regarding the alternative applications of kojic acid and derivatives as well as their safety, are encouraged.