I almost wrote that curls and humidity don’t get along. But the truth is, they get along too well. Hair loves moisture. When there’s heaps of it in the air (high humidity), your hair literally seeks it out. It’s drawn to the tiny water droplets suspended in the air like steel to a magnet. Don’t panic yet. There are some simple steps you can take to humidity-proof your locks.
By the end of this article, you’ll know exactly why your hair acts up on muggy days, and what you can do about it.
A closer look
As tiny as a strand of hair is, there’s a lot going on inside.
It’s actually made up of several chemically distinct layers. The diagram below shows what hair looks like under a microscope. For our purposes, we’re just going to consider the cortex and the cuticle. The cortex is made up of (dead) cells. They’re full of keratin-associated proteins and melanin. The outermost layer, called the cuticle, is made of overlapping (also dead) cells, like scales. This is why hair feels smooth if you run your fingers from root to tip but there’s a little resistance in the other direction. The more porous the hair is, the more resistance you’ll feel, but more on that later.
If you’ve ever seen or had hair that is dry and breaking beyond repair, it’s because the cuticle is seriously damaged. The gaps between the “scales” of the cuticle allow water and other small molecules into the cortex. When products claim to “penetrate” hair, it’s not just a marketing word. Hair strands actually do absorb stuff! This is where humidity comes in. On humid days there are lots of water droplets suspended in the air. Some of which get absorbed into the hair strands.
What’s hydrogen got to do with it?
There’s a reason water loves hair more than other surfaces. A chemical bond called a hydrogen bond forms when a keratin protein molecule meets a water molecule. Remember how I said they were attracted like a magnet to steel? That’s almost literally true. The two hydrogen atoms in a water molecule have a slight positive charge. The nitrogen and oxygen atoms in keratin protein have a slightly negative charge. The result? They’re drawn to each other and form what chemists call a hydrogen bond. It’s a weak bond, but it’s strong enough to mess up how your hair looks! When the water is drawn into the cortex of the hair, it disrupts the nice smooth overlapping structure of the cuticle. The cuticle bulges and buckles under the pressure, making the strand of hair kink. Times this by a few thousand and you have frizz.
Why are curls affected worse?
First, let’s look at why curly hair curls at all. Not all hair strands are created identical. Under a microscope, they vary greatly in thickness, cross-sectional shape and porosity. The thickness and cross-sectional shape of the strand affect the curl pattern. A perfectly cylindrical hair falls straight and the flatter the cross-section gets, the curlier the strand is. Think of it like this - it’s easier to make a ribbon curl than a shoelace.
Because of this shape, a disruption to the cuticle of wavy, curly and kinky hair has a larger effect on how it falls. It’s more susceptible to getting bent out of shape than straight hair.
A word on porosity
Actually, several words. Porosity is super important in understanding curly haircare.
Porosity is another word for how absorbant hair is. Highly porous hair absorbs a lot of moisture. If you drop a strand into a glass of water, it will sink straight to the bottom. It will feel rougher if you slide your fingers along it from the end to the root. Porous hair also loses moisture easily. This is because the overlapping cells of the cuticle are “looser”. They flair up more and have larger gaps in between them, like a pinecone.
Low-porosity hair won’t absorb much moisture. If you drop a strand into a glass of water, it will float on top. This is because the cuticle cells are tightly packed and sit flat. Like a pinecone before it opens up.
You’ve probably already guessed that high-porosity hair responds to humidity more than low-porosity hair. Unless it’s very hydrated, it acts like one of those little silica moisture absorber pouches and becomes a magnet for moisture.
The porosity of your hair is one factor in determining how much and what types of product you should use. In general, high-porosity hair needs more products more often than low-porosity hair. It can handle more oil, more leave-in conditioner and more gel. Since less product absorbs into low-porosity hair, less is needed.
How to tell your hair porosity
To find out how porous your hair is, drop a strand in a glass of water and wait a couple of minutes. If it floats, it’s high porosity. If it sinks to the bottom, it’s low porosity. If it “semi-sinks” it’s medium porosity.
Another quick way to test is to run your fingers down and then up a strand of hair. Low-porosity hair will feel more or less the same in both directions. High porosity hair feels rough and bumpy from tip to root.
How to humidity-proof curls
So, we’ve talked about the structure of the hair strand a lot. What practical steps can you take to reduce humidity-induced frizz?
The first thing to know is if your hair cuticle is badly damaged, from colour, heat, product or otherwise, you’re going to have a harder time taming frizz. Despite what any shiny commercial tries to tell you, hair is dead and can’t “heal” itself. Split ends can’t magically reattach themselves. Don’t trust anyone who tries to tell you otherwise *cough* Pantene *cough*. You can manage damaged hair, but your best bet is to care for new growth properly.
I’m glad we’ve got that out of the way. There are two basic approaches to reducing the effects of humidity, and we recommend doing both. The first is to hydrate your hair. It will find water droplets in the air much less attractive if it’s already teaming with moisture. The second is to seal the cuticle with a physical barrier.
How to hydrate
When we talk about hydrating hair, we don’t mean wetting it. One element of hydration is water and the other is oil. You need both. The scalp naturally produces both (sweat and sebum) and they serve to keep hair strong and shiny. When moisturising hair, there are two things to keep in mind:
1. Don’t undo your scalp’s hard work
This is important. Your scalp is constantly producing moisturising, hydrating oils custom-made for your hair. If you use a shampoo with harsh detergents like sulfates, it will wash away all that hard work. Don’t do this. Either skip shampoo altogether or use a gentle, detergent-free shampoo. Either read up on all the no-go ingredients, skip shampoo altogether or buy a curl shampoo.
2. Use with a quality conditioner
If your hair is long, dry or high-porosity, your scalp’s efforts won’t be enough. Thirsty hair strands absorb the scalp’s oils long before they reach your ends. A good conditioner picks up where your scalp left off. It will contain high-quality oils that mimic those produced by your scalp. Avoid conditioners with silicones (any ingredient that ends with -cone). They’ll weigh your hair down over time. Opt for one with natural plant oils, like argan, avocado, hemp or chia.
Don’t rinse it all out! After conditioning as normal, rake a bit more through and leave it in. Every good quality, natural conditioner doubles as a leave-in. In fact, most leave-in conditioners are just regular conditioners, watered down.
How to seal in moisture
Once your curls are nice and hydrated, you want to seal that moisture in. High-porosity hair loses moisture as quickly as it absorbs it so this step is crucial! There are a couple of ways to seal.
The first is with a sealing oil. Good hair oil for curls is made up of both penetrating and sealing oils. What’s the difference? Penetrating oil has a short enough molecular structure to absorb into your hair along with the water. Sealing oils have longer molecular structures and sit on top of the strand, lightly coating the cuticle and locking in moisture.
Again, you want to avoid those pesky “-cone” ingredients. If hair is like a wooden deck, silicone is like a hard varnish. It’ll seal it, alright. So well that it won’t wash off with harsh stripping chemicals. Avoid mineral oils for the same reason. Who wants petrochemicals in their hair anyway? You’re after a mix of natural plant and seed oils. The best oil that both penetrates and seals is argan. It’s magical stuff.
To use a sealing oil, mix it through your leave-in conditioner before applying it. The conditioner acts like a carrier so the oil is evenly distributed. Alternatively, rake and scrunch a few drops into damp hair.
The second way to seal in moisture is with a curl gel. Gel is stickier than oil and really coats hair. The fixatives in gel also help your curl pattern hold together for more definition.
To use, apply a generous amount of curl gel to sopping wet hair. Don’t be stingy - you really want to coat those strands. Use a squeezing-scrunching motion to encourage curl groupings. It should make an extremely satisfying squishing noise. Let it dry completely (air dry or diffuse). Your hair will be stiff and crunchy. Think middle school slicked-back fringe. Do not fear! There is one step left. The final step is to scrunch out the crunch. Coat your palms with a little hair oil and scrunch your curls to break up that gel cast. Keep going until your curls feel soft and bouncy.
We recommend using both oil and gel for the most frizz control. Trust us, the lack of flyaways will shock you and everyone you know.
Okay, that was a lot of information. The basic thing to know is that water droplets in the air literally get inside your hair strand and mess them up. This will affect your hair more if it’s highly porous. There are two ways to humidity-proof your hair. Firstly, hydrate it. Water is only attracted to dry hair. Secondly, seal the cuticle with oil or gel, preferably both. That’s it! Now tell all your friends!
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