How to Prevent Bed Head: Causes, Habits and Fixes

Bed head is hair that has set overnight in the shape it was pressed into while you slept, often with frizz and tangles on top. How to prevent bed head comes down to two habits at bedtime: go to bed with dry, detangled hair, and wear it in a loose style without a hard tie; a smooth pillowcase lowers friction, only one of the three causes described below. To fix bed head in the morning, wet the bent section right through, not just on the surface, and let it dry in the shape you want.

What causes bed head

We see three causes behind bed head: hair sets in the shape it is held in while it dries, moisture from sweat or humid air loosens your style during the night, and friction acts on hair as it rubs against the pillow and against itself. We found no study that measured what a night's sleep does to the way hair looks, so what follows comes from research on the hair fibre itself.

Hair sets in the shape it dries in

A set is a shape that hair holds after drying in it; setting is the process that fixes it. Hydrogen bonds are weak links between the protein chains inside each hair; they break easily and form again. Water breaks many of them, so wet hair bends easily, and as it dries, new ones form and hold the shape it dried in. A 2016 study on animal hair showed both steps, and that water undid the set. A 2025 research letter on curly human hair, offered as preliminary evidence, links weak hydrogen bonds to such temporary shape changes.

Hair that is damp at bedtime, or softens with moisture in the night, sets in whatever shape it is held in as it dries. Where your head presses on it, that shape is a flat side; where a tie grips it, a kink or a dent. Wet hair at night is covered in our article on sleeping with wet hair.

Moisture loosens a set

Humidity is the amount of water vapour in the air, and hair takes up water from it: a 2007 laboratory study on human hair fibres found that they held more water and grew less stiff as humidity rose. Since water releases a set, sweat at the nape or humid air can loosen the style you went to bed with. The same is true of curls from a curling iron or rollers, which tend to drop sooner on a humid day; our guide on why hair won't hold a curl goes through that and the other causes.

Frizz is hair whose strands stand out from the rest instead of lying together. Humid air is widely said to make hair frizzier; a 2021 study that assessed hair by touch, not by eye, found that changes in humidity may affect how frizzy curly hair feels, through changes in its friction.

Friction and tangles

Friction is the resistance you feel when one surface slides over another. A 2025 review of hair friction research describes friction rising as hair weathers, that is, wears with age and treatment, mainly because hair loses a thin protective surface layer; bleaching, colouring and heat styling speed up that loss. The review also notes that the edges of the cuticle, the outer layer of overlapping cells, can catch on each other when hair slides towards the root, which raises friction. A 2010 study on tresses whose protective layer had been chemically removed found that they tangled when wet and stayed in that tangled shape once dry.

How to avoid bed head at night

To prevent bed head and stop waking up with it, go to bed with dry, detangled hair in a loose style held by a soft tie.

Cause	What helps at night
Hair sets in the shape it dries in	Our rule of thumb: go to bed with hair completely dry, roots included, because towel-dried hair is still damp and sets in whatever shape the pillow presses it into. Wear it in a loose top knot or braid, or a low ponytail if you never sleep on your back, with a soft tie and no metal clasp.
Moisture loosens a set	Dry hair at bedtime; sweat and humid air can still loosen a set during the night.
Friction and tangles	Detangle before bed, from the ends up. Your hair meets less friction on a silk pillowcase than on a cotton one.

A tight elastic or a metal clasp grips one spot all night, which is where a kink forms if the hair softens. Ties are compared in our guide to hair ties that don't damage hair. A loose style matters for a second reason: a 2021 clinical report on patients with afro-textured or curly hair names “nocturnal traction”, the pull of styles that put tension on hair overnight, as a possible risk factor for traction alopecia, hair loss from repeated pulling.

Short hair has little to tie, and a pressed flat spot usually lifts once it is wetted through and dried again in the morning. The full night routine, by hair length and type, is in our guide on how to protect hair while sleeping.

Does a silk pillowcase help with bed head?

A silk pillowcase does not stop bed head: of the three causes we see, friction is the only one a pillowcase is known to affect. A cotton weave has a more textured surface, while silk's is smooth and dense, so hair slides over silk at night with less friction.

People who sleep on silk often report fewer tangles and less frizz in the morning. These are accounts from users, not measured results. No pillowcase repairs hair that is already damaged.

Nothing in the research on how hair sets suggests a pillowcase changes dents from pressure or a set loosened by moisture, and we found no study measuring how pillowcase fabrics affect the way hair looks in the morning. The two fabrics are compared point by point in our cotton vs silk pillowcase guide.

How to fix bed head in the morning

You can fix bed head without washing your hair by wetting only the bent or flattened sections right through and letting them dry in the shape you want.

• Dents, kinks and a flat side: since water releases a set, wet the section right through rather than misting the top, then comb it into place and let it dry, or blow-dry it, in the shape you want.
• Flat roots: dampen them, lift them with your fingers or a brush and dry them with a little air from a hairdryer, aimed upwards. For straight hair and blowouts, see our guide on how to keep hair straight overnight.
• Frizz: dampen the frizzy parts and smooth them down with your hands. Curls are refreshed by pressing each dampened section back into its clump, as described in our guide on how to sleep with curly hair.
• Tangles: work from the ends up, holding the hair above the knot. The 2025 friction review notes that conditioners can lower the friction of damaged hair for a while.

These are everyday styling steps, not tested methods.

What a night routine cannot do

Some bed head is normal, and on a humid or hot night, sweat and damp air can loosen any style. A silk pillowcase changes the friction your hair meets; we found nothing to suggest it changes the way hair sets. It does not change your hair's structure. Lengths that tangle badly every morning may be weathered or damaged, which is a case for a trim rather than a new night routine.

What our silk pillowcases are made of

The RENESSY silk pillowcases use 100% organic mulberry silk with a weight of 22 momme, and both faces of each case are silk. Mulberry silk comes from silkworms raised on the leaves of the mulberry tree, and momme measures the weight of silk fabric. The raw silk is rated grade 6A, a raw-silk grade that assesses several qualities of the thread together. GOTS, the Global Organic Textile Standard, certifies textiles made from organically grown fibres. The silk is GOTS certified. OEKO-TEX MADE IN GREEN is a label for textiles tested for harmful substances and made in traceable, certified production. The pillowcases carry the OEKO-TEX MADE IN GREEN label, and the label ID M27MNB1V9 can be checked on the OEKO-TEX website. The pillowcases carry the Dermatest 5-Star seal and the Dermatest Sensitive Skin seal, dermatologically tested for sensitive skin. A hidden YKK zip closes each case.

Frequently asked questions

What causes bed head?

From what is known about the hair fibre, bed head comes from hair setting overnight in the shape it was pressed into, from sweat or humid air loosening your style, and from friction against the pillow. Friction is only one of the three; dents, kinks and a flat side come from setting.

How do you fix bed head without washing your hair?

You fix bed head without washing by wetting just the dented or flattened sections right through and drying them in the shape you want.

Does a silk pillowcase stop bed head?

No, a silk pillowcase does not stop bed head, although your hair meets less friction on it than on a cotton pillowcase. Nothing in the research on how hair sets suggests it changes dents from pressure or a set loosened by moisture.

Why is my hair flat on one side in the morning?

Hair that is flat on one side in the morning was pressed against the pillow for hours and set in that flattened shape, especially if it was damp at bedtime.

Sources

• Cloete E, Ngoepe MN, Ismail E, et al. Weak hydrogen bonds in temporary shape changes of curly human hair fibers: preliminary evidence. Journal of Investigative Dermatology. 2025;145(1):185-188. doi:10.1016/j.jid.2024.06.1282
• Gao T. Evaluation of hair humidity resistance/moisturization from hair elasticity. Journal of Cosmetic Science. 2007. PMID 17728940
• Samrao A, McMichael A, Mirmirani P. Nocturnal traction: techniques used for hair style maintenance while sleeping may be a risk factor for traction alopecia. Skin Appendage Disorders. 2021;7(3):220-223. doi:10.1159/000513088
• Skedung L, Collier ES, Harris KL, et al. A curly Q: is frizz a matter of friction? Perception. 2021. doi:10.1177/03010066211024442
• Tanamachi H, Tokunaga S, Tanji N, et al. 18-MEA and hair appearance. Journal of Cosmetic Science. 2010. PMID 20447366
• Weiand E, Rodriguez-Ropero F, Roiter Y, et al. Understanding and controlling the friction of human hair. Advances in Colloid and Interface Science. 2025. doi:10.1016/j.cis.2025.103580
• Xiao X, Hu J. Animal hairs as water-stimulated shape memory materials: mechanism and structural networks in molecular assemblies. Scientific Reports. 2016;6:26393. doi:10.1038/srep26393