Tips on how to dry your hair, in response to science

What’s one of the best ways to dry your hair, in response to science? Is it hair dryers, hair straighteners, towels, or simply leaving it to dry naturally?

I’ve fragile, expensively broken hair and check out lots of hair merchandise, so I’ve a particular curiosity on this. Right here’s the science of drying your hair.

The video is right here, hold scrolling for the textual content model…

Hair and water

First we have to discuss what occurs when hair will get moist. Hair has a sophisticated construction, with numerous completely different elements. Most of those like water, particularly the within (the cortex).

When your hair is correctly moist, like whenever you’re washing it, it soaks up water and swells. Undamaged hair can take in about 1/3 of its personal weight in water. Broken hair has extra gaps for water to fill, like a bubbly sponge, so it holds onto much more water.

Water makes hair weaker

A very powerful impression of water on hair is that it breaks hydrogen bonds.

Your hair is held collectively by numerous bonds, which give it its energy and form. A few of these (disulfide and ionic bonds) are fairly everlasting, and solely actually break with chemical therapies.

However hydrogen bonds are momentary – they break and reform on a regular basis. 

When your hair is dry, hydrogen bonds stick hair proteins to hair proteins. It’s form of like they’re holding fingers. They’re basically glued collectively at a molecular degree.

However water can additionally kind hydrogen bonds. So when your hair is moist, your hair proteins begin bonding with the water as an alternative of with one another:

These are a bit such as you and your canine at a canine park. You have got a powerful bond, he comes whenever you name him.

However including water is like including a complete bunch of actually pleasant puppies. You’re each having interactions with all these new puppies, so that you and your canine have a quickly weaker bond. 

When these different water/puppies go away the hair/park, you and your canine have a stronger bond once more.

The issue: water isn’t hooked up to something. The hair proteins are much less glued collectively, so it’s like a ladder with entire bunch of damaged rungs (I’ll by no means run out of analogies for this).

Your hair is weaker, as a result of there are much less hydrogen bonds holding it collectively. In case you’ve ever observed that your hair is stretchier when it’s moist, this is the reason.

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Water makes hair rougher

On high of this, the cuticle scales on the floor of your hair (these overlapping roof tiles) don’t take in water evenly.

When dry, the cuticle scales of the hair are mendacity down comparatively flat and compact:

However when moist, the underside of every scale (endocuticle – yellow) and the glue between the scales (cell membrane advanced or CMC – purple) absorbs extra water than the resilient high (exocuticle – brown). They increase erratically, so the cuticle scales stick up, away from the hair:

This implies the scales get snagged and chipped extra simply.

So water itself isn’t very damaging to hair. However moist hair is extra fragile, so any bodily trauma will usually trigger magnified injury. (There’s one huge exception, detangling curly hair – take a look at this submit that explains this.)

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You may’ve heard about “hygral fatigue”, the concept that water itself damages hair – the proof doesn’t actually help this. We’ll revisit this level a bit later.

Drying hair and approach

What this implies for moist hair? With any technique, approach makes an enormous distinction.

Towel drying: Rubbing your hair such as you’re making an attempt to begin a fireplace may be very completely different from blotting and squeezing it gently – you’ll be able to think about the guidelines of the cuticle scales bashing towards one another.

Blow drying: Yanking your hair violently with a spherical brush may be very completely different from gently spreading out the hair together with your fingers and transferring it round.

Air drying: Sleeping on moist hair and smooshing it into your pillow with the complete weight of your galaxy mind, or jamming your hair between your again and the sofa as you watch a traumatic film could be very damaging.

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Hair and warmth

The opposite huge factor we have to discuss is warmth. Warmth could cause lots of several types of hair injury:

One other potential drawback is bubble hair. In case you warmth moist hair above ~90 °C (194 °F), the water inside can evaporate sooner than it will probably escape. It boils explosively and punches its approach out, leaving bubbles inside your hair. Your hair is mainly popcorn.

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For all of all these injury, extra warmth causes extra injury. There are additionally some modifications that don’t happen till specific temperatures – injury is especially extreme from round 180 °C (356 °F).

Utilizing a regular hair straightener on dry hair could cause lots of injury in the event you aren’t cautious. However utilizing one on moist hair is likely one of the most damaging issues you are able to do – in the event you hear snaps and crackles, that’s water boiling shortly, and a few of that is likely to be turning your hair into Rice Bubbles.

Blow dryers don’t make your hair anyplace close to as sizzling, so that you in all probability don’t want warmth defending merchandise for them. The water evaporating cools down your hair so it doesn’t warmth up as a lot, and air motion additionally helps hair dry. It’s greatest to maneuver the dryer round to dry your hair evenly, so that you’re not heating up strands which can be already dry for no good motive.

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The gap between the dryer and your hair additionally makes an enormous distinction, as seen on this examine. The researchers washed and dried hair samples on daily basis for 30 days with completely different drying strategies. They left some to air dry, and used a hair dryer at completely different distances. The additional away the hair dryer, the decrease the temperature, and the longer it took to dry:

• Air drying at 20 °C (room temperature) – takes 2 hours for hair to dry
• Hair dryer at 15 cm distance – hair reaches 47 °C, takes 60 seconds to dry
• Hair dryer at 10 cm distance – hair reaches 61 °C, takes 30 seconds to dry
• Hair dryer at 5 cm distance – hair reaches 95 °C, takes 15 seconds to dry

The entire blow-dried samples had injury to the cuticle scales on the floor (lifting and cracking), with increased warmth inflicting extra injury. There have been additionally indicators of bubble hair at a distance of 5 cm (hair temperature 95 °C).

These findings agree with different research. Cuticle cracking probably occurs as a result of warmth makes the skin of the hair dry and shrink sooner than the within – the within basically Hulks out, cracking the outer cuticle.

Bubble hair with hair dryers has largely been reported after they’re held shut, so the hair will get actually sizzling – more often than not, it’s curling irons and straighteners that trigger Swiss cheese hair.

Does air drying trigger extra injury?

This examine does have a bizarre discovering: the air-dried hair had some bulges within the CMC (the “glue” sticking cuticle scales collectively). The authors counsel the CMC is likely to be swollen and broken when it’s moist for too lengthy, they usually concluded that utilizing a hair dryer is much less damaging than air drying.

This hasn’t been replicated so far as I do know, and I don’t assume their rationalization is smart.

The examine used 20 cm lengthy human hair, which is about 1.5 years of progress. You’d anticipate all of the hair to have been washed and air-dried at the very least 30 occasions earlier than they had been collected, however solely the air-dried pattern had bulges. I think there’s one other rationalization – for instance, that pattern may’ve come from somebody with extra solar publicity, or one thing uncommon occurred to the pattern in the course of the examine.

So I don’t assume this examine actually helps the concept that air drying is extra damaging than blow drying. Nonetheless, air drying does go away your hair moist and fragile for longer, which could be unhealthy in some conditions (sleeping, traumatic films).

(I feel I’ve quoted this examine earlier than on this, earlier than I knew as a lot about hair science and earlier than I had the boldness to interpret research extra critically, so I’ve modified my thoughts. Sorry, I’m human, I get stuff incorrect!)

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Different advantages from completely different strategies

Hair injury isn’t the one facet to consider – typically, injury is price it! Bleach is likely one of the most damaging issues you are able to do to your hair, however I’ve gone by means of excessive bleaching from black to white 3 times, and I’m going to maintain doing it. Nonetheless, it’s necessary to know the advantages and dangers of various drying strategies, so you’ll be able to work out whether or not it’s “price it” for you.

Styling

You’ve in all probability observed that washing resets your hair’s form – like hair energy, it’s due to bonds.

Hair is glued into a specific form by everlasting and momentary bonds. When hair will get moist, water is available in and breaks a complete bunch of momentary bonds (principally hydrogen bonds). In case you hold your hair in a specific form because it’s drying, the momentary bonds that re-form maintain your hair within the new form. (Warmth may also break momentary bonds, and cooling permits new ones to kind.)

Whenever you wash your hair, momentary bonds break. Everlasting bonds pull hair again into its unique form, and that’s what you get when it dries except you maintain it in a special form. Hair additionally slowly reverts to its unique form over time with out washing, as a result of warmth and humidity additionally break momentary bonds.

Totally different methods work greatest to get specific types, and a few work higher whenever you use each warmth and water (e.g. blow drying).

Dandruff

In case your scalp is vulnerable to dandruff, it is likely to be a good suggestion to dry it shortly – which implies warmth.

One of many essential contributors to dandruff is overgrowth of a fungus, Malassezia. It’s naturally in your scalp, however causes points when there’s an excessive amount of. Air drying leaves your scalp damp for longer, which is ideal for fungal progress. It’s even worse if the moisture is trapped with a hat or a helmet.

You may need to contemplate warmth drying even in the event you don’t have dandruff, however your scalp is irritated – fungal overgrowth could cause irritation earlier than any seen dandruff reveals up.

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Time, effort, routine

There’s additionally effort and time, and the place issues match into your routine.

Microfibre hair towels and turbans can pace up drying with minimal effort and injury. These are product of a water absorbent materials that may kind hydrogen bonds. An extrusion course of creates small fibres with a a lot bigger floor space.

(The supramolecular/bodily chemistry rationalization of how these towels work: Whenever you contact the towel to moist hair, the water has two selections – it will probably stick with your hair, or stick with the towel. If the towel has extra hydrogen bonding websites that aren’t already holding onto water, it’ll stick with the towel. Larger floor space means extra uncovered hydrogen bonding websites – mainly, extra fingers for water to seize onto. Hydrogen bonds are actually underrated – I’m half satisfied they’re secretly operating the world.)

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Blow drying is extra effort and probably extra damaging (relying on approach), nevertheless it’s sooner. On the size of issues that injury hair, it’s fairly just a few ranges beneath oxidative chemical therapies like bleach and everlasting hair dye.

“Moist-to-dry straighteners” mix drying and styling within the one step. Many of those declare to be much less damaging (some even declare no injury), boasting options like decrease temperature plates (e.g. 120-140 °C), sizzling air, and sensors that modify the temperature in actual time. In my view, some do appear rather a lot much less damaging than utilizing an everyday straightener on moist hair. I don’t assume they’re more likely to be much less damaging than light blow drying or air drying, however they’re sooner and extra handy – it’s a compromise.

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Takeaways

Air drying, drying hair with low warmth, and mild towel drying are the least damaging methods to dry your hair.

Moist hair is way more vulnerable to mechanical injury. In case you’re going to rub your hair towards one thing (pillowcase, sofa), it’s in all probability greatest to dry it as a lot as attainable first.

In addition to injury, you may need to additionally contemplate hair fashion, scalp irritation/dandruff, time, and energy.

My private compromise:

• I attempt to wash my hair a bit earlier within the day (earlier than 7 pm). Bleached hair holds onto water higher and desires extra time to dry correctly –  if I am going to mattress with damp hair, it dries tough and bent, and I see extra break up ends the subsequent morning.
• I blot it with a traditional towel, then squeeze and wrap it with an Aquis towel for about 5 minutes (if I go away it longer, my fringe dries in a bizarre approach, and I can not restyle it for the lifetime of me with out correctly wetting it once more).
• In winter it takes longer for my hair to dry, and dandruff is mostly worse in winter for everybody – I don’t get a lot dandruff anymore, however my scalp does get irritated. I dry the highest of my hair, close to the scalp with a hair dryer – I’m nonetheless utilizing the Panasonic Nanoe dryer (hyperlink is for the brand new mannequin, I talked in regards to the older mannequin on this submit), which has a scalp mode that’s simply cool sufficient to not harm my scalp.
• Then I let my hair air dry. If it’s nonetheless damp just a few hours earlier than mattress, I’ll blow dry it once more. The Panasonic Nanoe has actually good warmth management, and I transfer it round rather a lot to dry it evenly and keep away from sizzling spots. I attempt to do that early so the within nonetheless has numerous time to dry correctly. If it nonetheless isn’t correctly dry at bedtime, I blast it with the blow dryer once more.

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References

Lee Y, Kim YD, Hyun HJ, Pi LQ, Jin X, Lee WS. Hair shaft injury from warmth and drying time of hair dryer. Ann Dermatol. 2011;23(4):455. doi:10.5021/advert.2011.23.4.455

Gamez-Garcia M. The results of lipid penetration and elimination from subsurface microcavities and cracks on the human cuticle sheath. J Cosmet Sci. 2009;60(2):85-95.

Gamez-Garcia M. The cracking of human hair cuticles by cyclical thermal stresses. J Cosmet Sci. 1998;49(3):141-153.

Gamez-Garcia M. Void and pore formation contained in the hair cortex by a denaturation and super-contraction course of occurring throughout hair setting with sizzling irons, J Cosmet Sci 2001, 62, 109-120.

Crawford RJ, Robbins CR, Curran J, Chesney Ok. A hysteresis in warmth dried hair. J Soc Cosmet Chem. 1981;32:27-36.

Krasnoff J, Glusac E, Bolognia JL. Bubble hair – a attainable rationalization for its distribution. Int J Dermatol. 1998;37(5):380-382. doi:10.1046/j.1365-4362.1998.00463.x

Mehregan DR, Sayoc L, Ramos D, Misra‐Higgins I. “Bubble hair,” a report of two circumstances. Int J Dermatol. 2006;45(11):1319-1320. doi:10.1111/j.1365-4632.2006.02699.x

Albers LN, Maley AM, MacKelfresh JB. Blowing bubbles: Dermoscopy of bubble hair. Int J Trichol. 2017;9(3):122-123. doi:10.4103/ijt.ijt_11_17

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