What Really Causes Dandruff? The Unexpected Facts

Do you think twice before wearing black? Hesitate before sharing a hat, pillow, or yoga mat? Constantly struggle with ruffling your hair or scratching your scalp? We get it. Dandruff (colloquially called ‘flaking’) really can affect every part of your life - and for many of us, it can be an ongoing embarrassment, annoyance, and sometimes even painful affliction. 

Fortunately, you’re not alone. Far from it. In fact, nearly 75% of people experience dandruff at some point in their lives, and roughly 20% get it chronically (all day, every day). Those impacted range from young children and adolescents to elderly people, and everyone in between. It is incredibly common, and yet for some reason, carries a stigma.

Dandruff: Background & basics

Dandruff flakes are simply large groups of skin cells that flake off of your scalp. This flaking can be triggered by a number of underlying causes, which we’ll get to later in this article. But here’s something that surprises most people: dandruff, or seborrheic dermatitis in its more severe form, can be caused by a combination of both intrinsic factors (your genetics) and extrinsic factors (i.e., diet, stress, exercise, weather, and pollution exposure). 

Taking a step back, the skin is your immune system’s first line of defense, and it coats itself in oils to keep invaders out. For some people, it has a hyperactive immune response that produces excess oils in the presence of microbes like yeast and bacteria. This irritates the scalp and may cause excess dead skin cells to build up.

And while dandruff can’t be cured, it can be controlled with a safe, simple treatment. 

But first, what are the root causes of dandruff?

The common causes of dandruff

Malassezia yeast overgrowth

Malassezia is a single-celled organism - a type of yeast - that lives on everyone’s skin. The presence of this naturally-occurring fungus on your scalp is the most common culprit behind dandruff, and the most likely cause of flare-ups for people with seborrheic dermatitis. When it consumes the oil your scalp produces, it excretes waste products, including oleic acid – to which many individuals are mildly allergic. Your body tries to protect itself by shedding large pieces of skin - the characteristic white flakes of dandruff that you see.

The easiest way to stop this cycle is with a Zinc Pyrithione-based shampoo. Zinc Pyrithione effectively rids your scalp from fungal causes of dandruff in two ways: 

First, it reduces the number of lipid-promoting enzymes on your scalp. When you get rid of the excess oils, the Malassezia fungus won’t grow and multiply. 

And second, the shampoo increases the amount of zinc and copper in the cells of your scalp, which control the yeast and prevent fungal overgrowth.

Dry scalp

Dandruff can also be caused simply by a dry scalp. Your scalp can be dry for a number of reasons - the weather, the kind of shampoo or styling products you use, or due to the natural effects of aging. Usually, if dry scalp is the cause of your dandruff, you’ll notice smaller, whiter flakes - as opposed to the larger, yellow flakes associated with seborrheic dermatitis. 

When you have a dry, itchy scalp, consider whether you may be over or under-washing your hair. Our scalps produce oil at different rates - so while a daily wash might be right for one person, it could lead to a dry scalp for someone else. If the frequency of washing doesn’t seem to be the problem, your shampoo or conditioner itself may be an issue. Choose a shampoo that treats flakes to cleanse and a conditioner that moisturizes to soothe your dry scalp.

Scalp psoriasis

Psoriasis is a common and chronic skin condition characterized by the build-up of excess cells on the skin’s surface. People with psoriasis suffer from areas of flaky, inflamed (red) skin. It can be itchy and/or painful, and a variety of topical ointments (both prescription and over-the-counter) have been used to treat it. 

Some with scalp psoriasis will try apple cider vinegar or tea tree oil to alleviate their symptoms. Apple cider vinegar can help relieve the itch, and sometimes removes psoriatic scale, but it won’t actually effectively treat the underlying condition causing the symptoms. And although many people believe tea tree oil helps with psoriasis and other causes of flaky skin or scalps, there is little clinical evidence that it does.

When psoriasis is localized to the scalp, Zinc Pyrithione shampoos can help relieve the symptoms. There is evidence that low levels of zinc can cause psoriasis, and experts recommend topically introducing Zinc Pyrithione to target the skin cells and normalize them.

Making dandruff disappear

Dandruff is incredibly common. And while it can’t be cured - it can be managed easily with the right products and approach. It’s the reason why we started Jupiter - to deliver modern, effective, beautiful products and content that gets your scalp in check.

Of note, try our Balancing Shampoo, formulated with Zinc Pyrithione (the key to stopping dandruff in its tracks), as well as clean ingredients like coconut oil and algae extract, to give your scalp the gentle care it needs to thrive. We know you’ll love it.