If you’re struggling with dark spots AKA hyperpigmentation, sun spots, liver spots and melasma – then kojic acid could be your new best friend.
Kojic Acid can help get rid of dark spots and hyperpigmentation in your skin. It is a known tyrosinase inhibitor. Tyrosinase the enzyme in your skin responsible for pigmentation production. If you stop tyrosinase signals, you can get rid of dark spots.
There is a lot of scientific research into kojic acid because of its ability to treat ‘abnormal melanin production’. That is just a fancy way of saying melanin makes dark spots.
What Causes Dark Spots
Your skin makes melanin (a pigment) from a melanocyte (a type of cell) in the deep layers of the epidermis in your skin. Melanin gets triggered in two ways.
First, by UV radiation from the sun. There are enzymes in your skin called tyrosinase (Tri-Roz-in-aze). These enzymes send a message to your melanocytes to make more melanin.
If tyrosinase could shout, it would sound something like this:
“Yo-yo melanocytes, the sun is laying down some heavy UV rays pump some melanin up here pronto! We need a tan. I repeat we need a tan! This is not a drill!”
Your melanocytes then jump into action and start pumping melanin to your skin’s epidermis (the top layer of your skin). When it gets there, it gives your skin a darker hue. Or more commonly known as a tan.
A tan does provide your skin with some protection from the sun. Don’t get too excited, though. A tan only gives an SPF of 3 or less!
Dark spots happen because too much melanin was pumped to the surface of your skin.
Acne can also cause dark spots to form because it causes inflammation. The skin sends tyrosinase to help heal the inflammation caused by acne. This triggers melanin to be produced around the wound site. When the acne is healed, the melanin remains and leaves you with dark spots and often scars.
The dark spots left after acne has healed called post-inflammatory hyperpigmentation (PIH).
Melanin is the main culprit in dark spots. Melanin production is triggered by tyrosinase, so stopping tyrosinase from interacting with the melanin is one way to lighten dark spots.
Kojic acid is well-known for being able to block tyrosinase from signalling melanocytes to produce melanin. It does this by penetrating the stratum corneum and binding to the tyrosinase. Think of kojic acid like the bouncer in a dodgy nightclub.
“Sorry, buddy I’m going to ask you to stop you right there. You will not be entering the deeper layer epidermis to ‘meet your friends’ tonight.”
What is Kojic Acid?
Kojic acid is a fungus found in wheat, barley, rye and rice. The Name Kojic comes from “koji” a fungus found in Japanese foods such as sake, miso and vinegar. It is called ‘kojic acid’ because it was discovered in Japan on kojic foods.
According to Dr Davin Lim, board-certified dermatologist “The kojic acid in skincare is formulated in a lab, but it does occur naturally.”
The reason kojic acid is made in a lab for purity and hygiene reasons. Because kojic acid is not oil-soluble and unstable at high temperatures, it needs to be broken down into an ester ( stable compound) before it can be used in skincare formulas.
Kojic acid has uses outside of skincare. It is used in the food industry to prevent food from going off to quickly (oxidising) and to preserve the colour in seafood (prawns and salmon).
Melasma and Hydroquione Cyclcing with Kojic Acid
Dr Lim is a fan of kojic acid when treating melasma with hydroquinone.
“This biggest use of Kojic Acid is in the inhibition of tyrosinase, which is your pigmented producing enzyme. Kojic acid is my favourite acid to use when I am ‘off cycling’ clients from melasma treatment”.
Melasma is a type of hyperpigmentation that may be triggered by hormones. It’s also known as the mask of pregnancy as its very common in pregnant women.
Hydroquinone is the current gold standard for treating melasma.
Hydroquinone really irritates the skin when used for extended periods. This means that some dermatologists will have a client do a cycle (1 – 2 months) of hydroquinone and then allow the skin to recover before starting another cycle.
Kojic acid is Dr Lim’s acid of choice to maintain the progress and keep melasma at bay until the next cycle of hydroquinone. You can use kojic acid on cycle for 1 – 2 months in between hydroquinone cycles.
You should only cycle hydroquinone and kojic acid under the supervision of a qualified dermatologist.
When talking about the best type and strength of kojic acid, Dr Lim says “In terms of effectiveness between 1% and 2% is good to start with. Don’t go above 2% or it can become irritating”.
How Does Kojic Acid Work
One of the biggest challenges when making effective skincare products is getting the active ingredients to penetrate the tough stratum corneum(SC). Kojic acid can penetrate the stratum corneum and interact with enzymes.
Anything that can penetrate the SC has the potential to be highly irritating to your skin. For this reason, when using kojic acid, you should start with a 1% solution.
At a 1% formulation means you will get the benefits of the kojic acid with minimal irritation.
How To Use Kojic Acid
Kojic acid works locally; this means that it will work where you put it. You can apply it to the whole face for an overall lightening effect, or you can apply it on targeted dark spots you want to treat.
Start by using at night after cleansing and before moisturizing.
Don’t use kojic acid with hydroquinone or retinol as your skin may become very irritated if your skin shows no signs of irritation, itch or redness, then your safe to apply it every night.
You want to work up to applying it twice a day. As it doesn’t increase your sensitivity to the sun, but you should always wear a broad-spectrum sunscreen every day anyway.
It’s best if you use kojic acid in cycles of 1 – 2 months. You should see a lightening effect after 3 – 4 weeks. Dr Lim recommends taking a photo of your pigmentation before using kojic acid and then taking another photo every week.
“It can be hard to notice a change when you look at your face every day! If, after 3 – 4 weeks, you are not seeing any photographic proof that your dark spots are getting lighter, then you should see a dermatologist”.
One of the tips to speed up the lightening process is twice weekly exfoliation. Use gentle chemical exfoliation, not harsh physical exfoliation.
We love facial radiance pads from first aid beauty. These pads contain lactic acid and leave your skin bright and glowly without feeling tight or dry.
If the kojic acid is doing its job, all those built-up hyperpigmented cells will slough off, and you’ll see fresh, lighter skin underneath.
Does Kojic Acid Have Side Effects
While this acid is effective, it’s effective because it’s powerful.
You can easily overdo things. Start with a 1% formulation, especially if your not under the care of a dermatologist.
Kojic Acid Can Cause Contact Dermatitis
Contact dermatitis is a rash that develops when you touch something, or something touches you.
There are two types of dermatitis.
Kojic acid like any skincare product can cause irritation which is why you should do a skin patch test before adding any new product into your skincare routine.
How To Do A Basic Skin Patch Test
Apply a small amount of the product to the inside of your wrist in the morning. If you notice any redness, swelling or itching within 6 hours, your skin does not like this new product.
If you have no symptoms, then you should be fine to put the product on your face.
Remember, contact dermatitis can build up over time, and kojic acid can irritate the skin. If you start to react, stop using it for a few days and see if the reaction settles.
Under no circumstances should you ever use raw kojic acid directly on your skin.
While you can buy it in that form, it will cause severe skin irritation.
Never use it unless you 100% know how to dilute it correctly.
I strongly advise you to buy kojic acid already formulated by a reputable brand.
Should You Use Kojic Acid
Kojic acid, when used correctly is a fabulous skincare product. Particularly useful is you’re dealing with dark spots, hyperpigmentation or melasma. It has added skin benefits of increasing brightness and clarity of your skin.
When it comes to dark spots and skin health in general, prevention is better than cure.
Wearing SPF 30 broad-spectrum sunscreen and staying out of the sun between 10 and 2 are good ways to prevent dark spots from forming.
Please note all backlinks are either to highly regarded academic publications, or interviews with a board-certified dermatologist.