Experts Say This Common Bedtime Habit "Can Create A Perfect Environment For Fungus And Bacteria"

Buzz Feed

07-03-2025

Old wives' tales warn that sleeping with wet hair can make you sick or increase your chances of catching a cold, but there isn't any scientific evidence that it can directly cause respiratory illnesses. However, there are risks associated with sleeping with wet hair, including hair and scalp damage. And fungus is involved.
When you wake up in the morning after sleeping on wet hair, you may find your hair smelling like mildew, harboring a stale and damp aroma similar to the smell of the early stages of mold forming, said Dusty Schlabach, a hairstylist and owner of Thairapy Salon in South Pasadena, California.
'If the hair is wet, all these conditions contribute to a much slower drying process, and can create a perfect environment for fungus and bacteria to thrive,' Schlabach said. 'If this happens often enough, it can grow into a real problem on the scalp causing yellow discoloration, itchiness, buildup and flakiness. All in all, it's gross. With enough buildup, it even stinks. I see it on new clients all the time.'
Fungi flourish in dark, moist and humid environments, and can live on the dead tissue of hair, nails and outer skin layers. As a result, your pillow is a breeding ground for fungus to thrive. A 2005 study by Wythenshawe Hospital and the University of Manchester found that there can be up to 16 types of fungal species found on your pillow.
You might also wake up with broken and tangled strands that can be hard to recover to their healthy state, especially for people with curly hair.
'The outside layer of the hair, the cuticle, is meant to expand when wet, and contract as it dries,' Schlabach said. 'If it stays stretched for too long, it can split and crack, compromising the health of that outer layer. It allows way too much penetration from water and products you might be using. This leads to dryness, which leads to brittleness, which leads to breakage, which visibly translates to stringy ends and frizz.'
In addition to hair breakage, we asked dermatologists about the types of fungal infections that can form in your hair, how your scalp is affected and what to do if you have to sleep with wet hair.
Types Of Fungal Infections
Malassezia
Malassezia species inhabit the skin of 90% of adults and usually don't cause any harm. The growth of these fungi may be attributed to humidity, sweating and oily skin, which can be a result of sleeping with wet hair.
Found in hair follicles, the fungus is also linked to a skin disease called dermatitis, a chronic form of eczema caused by genetic and environmental factors. An excess of Malassezia yeast can cause an immune system reaction that leads to fungal infections and skin changes.
Dermatitis is a broad category of conditions that share one common trait: they all cause inflammation of the skin, explained Dr. Peter Lio, an eczema expert and clinical assistant professor of dermatology and pediatrics at the Feinberg School of Medicine at Northwestern University.
'Typically this manifests as redness, swelling, scaling and dryness, but in more severe cases can actually cause things to open up and become oozing wounds,' said Lio, who is also a member of the National Eczema Association. 'On the scalp, the most common forms of dermatitis are seborrheic dermatitis and psoriasis, close cousins that typically manifest with flaking and scaling dandruff, dryness, and itch.'
Scalp Ringworm
Ringworm, or tinea capitis, is a fungal infection of the scalp hair. The fungi can make their way into your hair, affecting keratin and tissue, which causes your hair to become brittle and break. These fungi and their spores can remain on combs, brushes, unwashed towels, furniture and sheets for long periods.
Although most cases of scalp ringworm are caught from other people with the infection, one of the risk factors includes warm and humid environments where fungal spores may grow. Since fungi grow in wet environments, having wet skin or a wet scalp for a long period of time makes you more susceptible to developing the fungal infection.
'Despite the term 'ringworm,' there is no actual worm causing the rash,' explained Dr. Margarita Lolis, a board-certified dermatologist at Schweiger Dermatology Group in Hackensack, New Jersey. 'It got the name because of the circular patches it causes.'
The infection usually starts with red, round patches on the skin that may look like dandruff, causing itchiness, scale formation and alopecia. Similar to symptoms of dermatitis, ringworm can lead to patches of hair loss.
Although scalp ringworm is not a dangerous condition, it is contagious, Lolis said. 'If left untreated, it can lead to severe inflammation called kerion, which can drain pus and cause thick crusting on the scalp.'
Black Piedra
This rarer fungal infection affects the hair shafts by attaching to the hair and forming black nodules. Breakage of the hair can occur as a result of the nodules, and without treatment, the fungal infection may cause alopecia.
Black piedra is common in people with long hair with excessive hair oils, usually forming in hot and humid environments.
Unlike other forms of fungal infections, black piedra is asymptomatic and normal hair can be restored. However, it can be chronic, lasting for months or even years.
If You Sleep With Wet Hair, Try...
Drying Your Hair
It might be time to switch your shower schedule or try to let your hair air-dry before bed. However, if you don't have the time to wait for your hair to dry, blow-drying your hair might be better than sleeping with it wet.
'If a client needs to or prefers to shower at night, I'd highly recommend drying it before bed. For curly hair, use a diffuser to avoid heat damage,' Schlabach said. 'I tell my clients, 'If it's too hot for your skin, it's too hot for your hair.''
If you find yourself sleeping with wet hair regardless, it might be time to integrate products that can help prevent breakage and fungal infections.
Using A Silk Pillow
If you like to shower after a long day and don't have time for your hair to dry, a silk pillow can help to save your hair. Using a silk pillow can provide less friction on your hair when you're sleeping — even with wet hair, according to The Sleep Foundation, a non-profit that provides expert information for sleep issues.
Lea Brown, a hairstylist at Shine Aveda Salon + Spa in Sparks, Nevada, agreed. 'Wet hair is weak and can safely stretch up to 30% of its original length, stretching any further will cause breakage,' Brown told HuffPost. 'So, it's best to sleep with a silk or moisture-wicking fabric to prevent friction. Friction equals frizzy hair and breakage. Hair will have less shine, fullness and strength.'
Although a silk pillow can help to prevent breakage while you're sleeping, it doesn't completely prevent hair damage.
Using Anti-Fungal Products
Anti-fungal products such as shampoos and creams work to kill the yeast on your scalp and hair that causes infection and to prevent it from coming back. However, they do not clear the infection fully.
In addition to skin and hair products, oral anti-fungal medications might also be needed to treat infections that reach the root of the infected hair follicles. They can be prescribed by your doctor.
'Products that do treat the fungus, unfortunately, wind up drying out the hair, leaving it brittle and dull, leading to breakage and frizz,' Schlabach said. 'If they only knew to stop sleeping with wet hair in the first place — they wouldn't need to trade one issue for another.'
Switching Your Shower Routine
If you can make time to shower in the morning, it can help promote skin and hair health, Lolis said. 'Morning showers help combat oily hair and scalp. If you wash your hair at night, by the time you wake up it could still look oily. To ensure a fresh and clean style, it's best to wash in the morning.'
Additionally, since our body releases toxins and bacteria, such as sweat, while we're sleeping, showering in the morning removes sweat and buildup.
'There is no right or wrong time to shower, but the most important thing to remember is to ensure you are using lukewarm, not boiling hot water, and gentle soap to cleanse,' Lolis said.