Hair mould. Even the word is icky, let alone the image it conjures up of some kind of sticky, subterranean swamp on our scalps. But it would appear that concerns over sleeping with wet hair are not only suddenly a major talking point in my Whatsapp group, but Google search for the term ‘hair mould’ is on the rise, too.
One reason for this is the ‘skinification’ of scalp care. We've come to recognise that the scalp is just an extension of the skin on our foreheads. A knock-on effect is that we are also hyper aware of any changes to its surface – spots, flaking, sensitivity – and the arsenal of soothing toners, masks and scalp serums out there that could provide solace.
But that's not all. The idea of blow-drying wet strands to avoid ‘hair mould’ growing on your scalp is gaining fame on TikTok. A video from influencer @danicolexx, captioned ‘hair mold ain’t getting past me' has over 2.5 million views, while another by @allthingskaley has 21.6 million views.
TikTok content
TikTok content
When I pitched this story to the GLAMOUR team, the room fell silent. 15 heads snapped in my direction, with eyes pleading for reassurance that sleeping in their favourite hair mask, or air-drying their hair overnight wasn't really bad for you.
And I'm holding my hands up here – I didn't know the answer.
Is hair mould just TikTok fear-mongering?
In all my years as a beauty editor I've never heard the words “hair mould” bandied around by trichologists or hairstylists – and, on days when I go to the gym after work, I'm a wet hair sleeper as I shower just before bed. So should I be worried that my scalp is a walking petri dish, I asked hair expert Andy Jones, Chāmpo’s head of product development?
“While it’s unlikely for mould to grow on the scalp or hair itself, frequently sleeping with wet hair can create a damp environment on your pillowcase, which may harbour bacteria over over time," Andy says. "This can occasionally lead to scalp irritation or fungal infections. Additionally, a damp scalp can disrupt its natural microbiome, increasing the risk of dandruff or irritation.”
OK, so ‘mould’ is a bit of a stretch and it's certainly not the same grey fuzz or black sludge you might find on fruit that is past its sell-by date or a damp wall. But it is possible to get a fungal infection as wet hair and the warmth from your pillow create the perfect (humid) breeding ground for certain bacteria and fungi to thrive.
These include a type of yeast called Malassezia, which typically causes dandruff, as well as seborrheic dermatitis. You may also find yourself contending with fungal folliculitis – an infection of the hair follicles, which shows up as small, red, acne-like bumps on the scalp.
Is sleeping with wet hair bad?
Aside from the possibility of a fungal infection, another reason not to sleep with wet hair is that you run a higher risk of breakage. Put simply, when wet, the cuticle (the outer layer of hair) opens and swells and makes hair strands stretchier and weaker, explains hairstylist Adam Reed.
Tossing and turning in your sleep, as well as soggy strands rubbing against your pillow, could cause excess pulling and split ends. “Wet hair is more fragile than dry hair, making it more prone to breakage caused by friction while sleeping," Andy adds.
Rest assured, there are ways to mitigate these unpleasant effects.
How to keep your scalp healthy:
- Try not to go to bed with your hair soaking wet. Instead, squeeze out any water with a microfibre towel and use a low heat and speed setting on your hairdryer to rough dry your hair. Good hair dryers designed to minimise damage and blow dry fast include Dyson Supersonic Nural and Shark SpeedStyle Hair Dryer.
- If you do occasionally sleep with wet hair, off-set possible damage. “Apply a leave-in or protective hair treatment and loosely braid long hair,” Andy recommends. "Switching to silk or satin pillowcases can also help reduce friction and breakage.”
- Keep your scalp clean and avoid product buildup. “Use a gentle, pH-balanced shampoo to maintain the scalp’s natural barrier, and opt for lightweight conditioning and styling products that don’t clog the scalp,” says Andy. All Chāmpo shampoos and conditioners, for example, are acid balanced, with a pH between 5.5 to 6.5.
- Promote circulation. “Massaging the scalp with your fingers or a shampoo brush helps boost blood flow, and promotes a healthy scalp environment,” he adds.
- And if your scalp is suffering from a fungal infection, use an anti-fungal or clarifying shampoo. "These can be helpful to restore balance and remove buildup," Andy notes. "Always ensure your hair is completely dry before bed to prevent recurring issues and if irritation persists, consult a dermatologist.”
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