With the extra hype about skincare these days, kojic acid has come into the limelight. You might consider it something harmful due to the word “acid,” but the case is the opposite. It has become a part of the regimen practiced by dermatologists worldwide, and the results are leaving everyone speechless!
Let’s explore the benefits of kojic acid on the skin!
What is Kojic Acid?
In 1907, the first form of kojic acid was identified in Japan. It is sourced from a fungus named Aspergillus Oryzae, which is normally used in fermentation and to saccharify food in Japan. This fungus is now known as the koji mold.
It is beneficial for the skin because, unlike other skin lightening products that exfoliate the outermost layer of dead skin, it works deeper. It reduces the production of tyrosine, an amino acid required to form melanin in the body. Melanin affects hair, eye, and skin color. It lightens the skin tone since it inhibits the production of melanin. 
How long does it take to lighten your skin tone?
It can answer several skin problems ranging from acne, acne spots, melasma, and sun damage. Normally, it is also used as a combination with creams and serums. Once you start using it, results will show within 2 weeks. Results will improve and be seen faster if glycolic acid is also used alongside kojic acid.
If you’re looking to lighten your skin tone, then this is not the solution you need. However, if you have skin pigmentation and scarring, it will do wonders for your skin. More importantly, you need to use it in a safe amount.
Studies have been conducted on the safe concentration of it that can be used. 1% to 4% concentration of this acid is safe to use in cosmetic products. A combination consisting of 2% kojic acid and 2% hydroquinone or 4% kojic acid and 4% glycolic acid has proven effective for pigmentation treatment. However, if you increase the dosage of kojic acid to more than 4%, it may cause skin irritability. 
Uses of Kojic Acid
It is used topically on the skin to treat skin problems. Also, it has been approved for usage in cosmetic products with a 1% concentration or less. It is found in powders, soaps, serums, creams, and cleansers. Depending on the instructions provided, powders are normally mixed with water or lotion.
Soaps and cleansers, including kojic acid, should be washed off instantly. Creams and serums are applied to the skin so they can be absorbed. Kojic acid face masks should be used occasionally, but cleansers and soaps can be used daily. It can be used on any non-sensitive area of the skin but mainly on the face and hands.
Benefits of Kojic Acid
It has a lot of skin benefits, which include:
Due to a hormonal imbalance, primarily due to pregnancy, dark patches form on the skin. It can lighten these pigmented dark areas.
It protects the skin from UV rays and stops sun damage. This keeps the skin safe from wrinkles and fine lines that cause skin aging.
Since it works to lighten dark areas on the skin, it helps reduce acne and other types of scars on the skin. It doesn’t change the thickness of scar tissue but lightens the affected area.
It also has certain antifungal properties that effectively treat and prevent fungal diseases such as ringworm, athlete’s foot, yeast infection, and candidiasis. Kojic acid soap can be used to treat these fungal infections. 
It can also prevent and treat many types of bacterial infections caused on the skin. It is highly effective in reducing acne caused by bacteria on the skin.
Side Effects of Kojic Acid
Despite having multiple benefits associated with it, kojic acid for the skin also has certain risks and side effects that need to be considered. Kojic acid, while lightening the skin, can also cause a mild side effect called contact dermatitis.
Symptoms of contact dermatitis include redness, rashes, swelling of the skin, irritation, itchiness, and discomfort. Contact dermatitis might occur when people use more than the instructed amount of it.
Since it reduces melanin production, which actively protects the skin from sun damage, it might end up making skin vulnerable to skin damage. This is one of the reasons why it shouldn’t be used for more than 3 months. Moreover, if your skin is broken or damaged, don’t use kojic acid at all. It may worsen your skin condition and cause further damage.
To prevent it from causing serious side effects, you should take the following precautions:
- First and foremost, consult your doctor before using kojic acid on the skin, especially if you have any prior skin conditions or allergies.
- When using kojic acid products, be sure to read the instructions before applying them to your skin.
- If kojic acid products are prescribed by your doctor, then only use them as directed.
- If using kojic acid products is causing irritation and rashes on the skin, discontinue usage immediately and discuss the reaction with your doctor.
How to Effectively Use Kojic Acid Soap
Kojic acid soap can be used on the skin daily. To make sure that it proves to be beneficial, you should follow these instructions:
- Massage the soap on your skin for at least 2 minutes for effective results.
- Rinse off the soap with warm water.
If you have sensitive skin, you should avoid using it on your skin.
Kojic Acid vs. Hydroquinone
Hydroquinone is another skin-lightening agent which can be combined with kojic acid for better results. Also, hydroquinone is found naturally in certain foods like coffee and fruits. It works similarly to kojic acid by controlling tyrosinase, which controls melanin production. It also kills cells producing melanin in the skin.
A study using both kojic acid and hydroquinone for treating melasma was conducted in 1996. It showed that 51% of the participants responded equally to both kojic acid and hydroquinone, 28% saw a dramatic improvement in the skin where kojic acid was applied, and 21% saw better results with hydroquinone. 
Since both can be used together and have shown better results on the skin, it is advised that they be combined. However, every skin type is different and may react differently depending on various factors. Using kojic acid and hydroquinone together may cause skin irritation and redness, which reduces by the third week of usage.
Bottomline: Kojic Acid for your Skin
Kojic acid can do wonders for the skin, but it is important to use it within the instructed amount and with a doctor’s consultation. Since hydroquinone and kojic acid work better together, you could use this combination for faster and better results on the skin.
Disclaimer: This article is only a guide. It does not substitute the advice given by your own healthcare professional. Before making any health-related decision, consult your healthcare professional.
Editorial References and Fact-Checking
- Brtko, J., Rondahl, L., Ficková, M., Hudecová, D., Eybl, V., & Uher, M. (2004). Kojic acid and its derivatives: history and present state of art. Central European journal of public health, 12 Suppl, S16–S18.
- Europa – Public Health – Risk Assessment. (n.d.). Scientific Committee on Consumer Products. Retrieved August 28, 2022, from https://ec.europa.eu/health/ph_risk/risk_en.htm
- Kim, J. H., Campbell, B. C., Chan, K. L., Mahoney, N., & Haff, R. P. (2013). Synergism of antifungal activity between mitochondrial respiration inhibitors and kojic acid. Molecules (Basel, Switzerland), 18(2), 1564–1581. https://doi.org/10.3390/molecules18021564
- Garcia, A., & Fulton, J. E., Jr (1996). The combination of glycolic acid and hydroquinone or kojic acid for the treatment of melasma and related conditions. Dermatologic surgery : official publication for American Society for Dermatologic Surgery [et al.], 22(5), 443–447. https://doi.org/10.1111/j.1524-4725.1996.tb00345.x