Let’s Talk Hair Anatomy


 - By Kailey Bradt

Let’s Talk Hair Anatomy


Wondering why we are even thinking about the anatomy of hair? Wondering why you should know the anatomy of your hair? It’s simple. You want to take care of your hair and it’s important for you to understand what your hair actually is made up of, so you can make the best decisions for your hair type, texture and condition. Do you color your hair? Highlight your hair? Do you feel build up on your scalp? Is your scalp oily and your ends dry? Is your scalp dry? You will be able to make the right decisions to maintain healthy hair and design your hair care routine specific to you once you know just a tiny bit of science and understand what’s actually going on with your hair & scalp.

Starting with the Basics

We are going to keep this first post simple. And though you’ve probably already heard some of these terms, we’re laying the groundwork to build up to everything there is to know about your hair, and scalp (let’s not forget the scalp, but we’re saving it for another post), so your routine makes sense and you don’t have to try 756 different products to try to get the results you want.

The Hair Shaft

There are three main components to the hair shaft: cuticle, cortex & medulla.

Cuticle: The outermost layer of the hair shaft that protects the more delicate layers. 

Cortex: The middle layer of the hair shaft that forms the bulk of the hair shaft and is responsible for your hair color.

Medulla: The innermost layer of the hair shaft.

What is Hair?

To be able to go into detail about the different structures within the hair shaft, we need to know what hair is. When you ask someone what hair is, they probably can’t tell you. But, when you ask your slightly nerdy, very chic friend who works in beauty what hair is, here is what she’ll tell you.

“Hair is made up of mostly keratin, which is why you’ve heard about keratin. Keratin treatments, keratin shampoo, vegan keratin. So much to talk about keratin. But if you’re hair was just a protein, and even though keratin is a strong, hard protein, everyone would have the same hair. And we don’t. Hair is unique to each and every one of us. So even though keratin can make up anywhere from 65% to 95% of hair, there is also 15% to 35% water, which is why we commonly talk about ‘hydrated’ hair. And since you know hydration comes from water, you’re probably wondering why you’re using a hair oil… that’s because 1% to 9% of your hair is made up of lipids. Lipids are fats, waxes, oils- hence your hair oil. And what about that color?! Your hair has color, whether it’s natural or you process your hair in some way, pigments, minerals and a few other things make up less than 1% of your hair. Crazy right.” - Kailey, your nerdy science friend who loves beauty & is also the founder of Susteau

Photo Source: Hannah Thornhill for Susteau

What is hair source: Comprehensive Biomaterials II, Elsevier, 2017, Pages 542-557, ISBN 9780081006924