
What Causes Dandruff and How to Fight It
We list down six common causes of dandruff to help you understand the root of this hair and scalp woe.
Dandruff is a common scalp condition that affects one out of every five people, according to the Columbia Skin Clinic website. While it is usually not serious, it can be uncomfortable, especially with the scalp itching and flaking that comes with it. But don’t worry! We’re here to discuss what causes dandruff to help you find the right treatment.
Common Causes of Dandruff in Hair
One of the causes of dandruff is an overgrowth of the fungus Malassezia. Credit: Hariono Halim
1. Fungus
The presence of a fungus called Malassezia on your scalp is a common hair dandruff cause. It exists on your scalp, whether you have dandruff or not. However, your scalp can get irritated when there’s an overgrowth of this fungus and you have a weak scalp barrier.
2. Oily Scalp
If your scalp is oily, you are more likely to get dandruff. “Malassezia uses sebum and other lipids in the scalp as nutrients and then converts these into waste materials that can penetrate the scalp and cause an inflammatory response,” explains Peter Bailey, a former research and development manager at Unilever.
3. Dry Scalp
Having a dry scalp doesn’t mean you’ll automatically get dandruff. However, it can make the itching worse and lead to flaking.
4. Dirt and Product Residue
Shampooing your hair removes excess oil, dirt, and product residue. When you don’t shampoo thoroughly, these things clog up your pores and cause irritation, which can then lead to dandruff.
5. Heat and Humidity
“In very hot countries, it is likely that the local humidity around the scalp is increased which could lead to an increase in Malassezia growth, ultimately leading to an increase in the occurrence of dandruff,” explains Peter. This may explain why your scalp starts itching and flaking when the hot summer months start rolling in.
6. Harsh Hair Care Products
If your scalp is sensitive, it can get irritated when you use certain hair products. Your scalp might even have an allergic reaction—a condition known as contact dermatitis. According to the Columbia Skin Clinic website, contact dermatitis “will likely result in dandruff.”
How to Treat and Manage Dandruff
“The most common way to treat dandruff is with a shampoo [containing an anti-fungal ingredient] whose primary role is to remove Malassezia microorganisms from the scalp,” explains Peter. “By removing them, the main source of attacking toxins is removed and the scalp skin can then start to recover and rebuild its protective scalp barrier.”

Anti-dandruff shampoos usually have anti-fungal agents like zinc pyrithione and piroctone olamine (Octopirox) to treat the causes of dandruff. These shampoos also have keratolytic agents like salicylic acid to deal with the symptoms.
If you have recurring dandruff, try CLEAR Cool Sport Menthol Anti-Dandruff Shampoo for Men. It has piroctone olamine, which stops the growth of microorganisms like Malassezia. This shampoo also removes, resists, and prevents dandruff, thanks to its Triple Anti-Dandruff Technology. It penetrates deeply and gives your hair and scalp more germ-fighting power compared to regular shampoos.
Peter also says you can use an anti-dandruff shampoo even if you don’t have dandruff. Doing so can help prevent dandruff by removing Malassezia from the scalp. “However, many people who don’t have dandruff today may never get dandruff due to their individual scalp skin physiology,” he adds. It all boils down to how strong one’s scalp barrier is and its ability to protect your scalp from irritants.
Switching to a milder shampoo can also help you manage dandruff. “We know that harsh cleansers can damage and weaken the scalp barrier so [use] a milder surfactant system,” says Peter.
Dandruff can make you uncomfortable, but you don’t need to panic. Knowing its causes can help you find the best treatment and keep your scalp flake-free.