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Dec 12, 2020
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What Is A Hair Cuticle?

Let's learn more about your hair's first line of defense against damage ⚔️


To understand what a hair cuticle is, you'll first need to know a bit more about basic hair anatomy (which is way more fun than the Anatomy class you took in high school, we promise.)

Hairs are made up of 3 basic parts:

the cuticle (the protective layer which we're learning about today)

the cortex (the thickest layer, and also where the majority of the pigment is concentrated)

the medulla (the very thin inner layer -  some hairs don't even have it.)


Hair is structured so that the cortex and the medulla make up the core of the hair strand. The cuticle surrounds and protects them both from outside stressors.

These stressors can include water, the sun, heat tools, combs, brushes, hard water... there are a lot of things out there that can damage your hair. 


Protection is a big job so the cuticle is a complex layer -- it's made of millions and millions little scales that are layered on top of one another. These scales point downwards, away from your roots, and are shaped to limit friction between individual hairs. Close up, they look like roof shingles or scales on a fish, and move against each other so that your hair is able to bend without flaking off scales.

⭐ Your cuticle is the most tactile part of your hair and you can experience the shape of the scales yourself without a microscope. Pinch a strand of your hair and run your fingers from the hairs root to its tip. Smooth and easy? Now, do the same, but from the opposite direction: pinch from the tip of your hair and feel upwards. Not as fun and kind of squeaky? When you run your fingers from your tip to your root, you run into the rough edges of the scaley layers of your cuticle- it doesn't feel good.

Cuticle Thickness and Racial Heritage

A thick cuticle typically means that the vulnerable parts of your hair (the medulla and cortex) are better able to withstand damage. This thickness often has a relationship with racial heritage. For example, people who are of Asian descent often have the most layered cuticles, while people who are of African descent have more thinly layered cuticles. This is one of the reasons why Afrotextured hair is so prone to damage despite how coarse each individual strand feels - the protective layer is not very thick.

What does a healthy cuticle look like?

A healthy cuticle is a smooth, closed cuticle with scales that are fully intact. This kind of cuticle produces a lot of shine, since its scales are at the correct angle to reflect the largest amount of light. It doesn't tangle against other hair and feels smooth to the touch.

What does a damaged cuticle look like?

A damaged cuticle is rough and dull, with scales that are either raised or stripped away. This kind of cuticle leaves the vulnerable core of the hair fiber exposed. Hairs that have damaged cuticles are also very tangly, as scales that normally point downwards have been raised so that they cause friction.

Can you open/close a hair cuticle?

...kind of. Opening the hair cuticle is the easy part. If you've ever colored or bleached your hair, you've already successfully opened your hair cuticle. In order for the hair color to "stick", it has to get slipped under the scales and into the cortex.

You also open the hair cuticle a little bit every time you wash your hair, or even just get it wet. Water and shampoo both deform the shape of the cuticle, which is why we advise both rinsing and washing hair only a few times a week. But closing the hair cuticle? That's the tricky part. Once the hair cuticle becomes deformed, it's not very easy to smush back into its prior shape. You can "glue" the cuticle back down and "patch" the places where it's been stripped away with the oils and silicones in a conditioner, but those scales probably won't pop into their prior shape all on their own. This is one of the reasons bleached/colored hair is so high-maintenance in comparison to virgin hair- these processes are inherently damaging to the hair fiber, and require a ton of TLC (limiting brushing, conditioning every time you wash, limiting heat styling, et cetera) to counteract in any effective way.

How can I protect my hair cuticle?

For starters, you'll likely benefit from a hair product that contains a high-quality silicone. Silicones are often misunderstood and maligned, but they're some of the most effective hair care ingredients out there.

Silicones are basically a suit of armor for your hair - they work by covering hair with a super thin hydrophobic coating. Not only do silicones keep the bad stuff out, they also keep the good stuff in. Bye bye, cuticle heat damage, hello locked-in moisture.

You can also take them on and off as you please; a quick shower will remove the silicone layer from your cuticle STAT.

One that we use in our products is Propoxytetramethyl piperidinyl dimethicone - a long name for an awesome ingredient. It's a unique, patented silicone that protects hair from heat, UV rays, and other environmental factors. It also increases hair volume, softness, and shine, and acts as a free radical scavenger - a big win all around.

I think my hair cuticle is damaged. What do I do?

👋Hi! You've come to the right place! We'll start out by matching you to your own personal chemist, and then the journey of healthy hair will begin. Start here!

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Caroline Schmidt
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 Staff
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