What is Porosity? Why is it Important?

Porosity is often said to be an important part of effectively caring for kinky & curly hair... but what is it really all about? We give you a no non-sense break down of what porosity is and why you should care.


What is Porosity?


When it comes to your hair, porosity is one of the MOST important factors that lends to health coils. Understanding your hair’s porosity means you understand how your hair absorbs and retains moisture. Note that porosity is genetic; but it can be altered by things like bleaching, coloring, and direct heat.


Wondering how moisture is retained within your hair strands? First, let’s explain the structure of hair. Hair grows out from the epidermis (outermost layer of the skin) on the scalp, while the hair follicle is located in the dermis layer (second layer of the skin). Each strand of hair has three layers: cuticle, cortex, and medulla. The cuticle is the outermost layer to the hair shaft, the visible hair not located in the follicle. It is porous, aka made of layers of cells that contain spaces that allow liquid to pass through, that help protect the inner layers of the hair shaft. The second layer is the cortex which controls water and hair products that enters and exits the hair. This layer is controlled by inherited genes, (shout out to moms and pops!) and determines the hair strength, color, and texture. The third layer is the innermost layer and is very soft and is only present in the thickest strands of hair.


What Determines your Porosity?


Your hair structure will determine your porosity. The cuticle, the outer layer, is built of shingles that lay on top of one another. (Think of those black things on the roof of a house.) When these shingles are raised, water and hair products can enter the hair shaft and moisturize the hair. When sealing in moisture, it’s best to make sure that the cuticles remain closed so that the moisture stays within the strand.

There are three levels of porosity: high, medium, and low. High porosity has cuticles that are spread out and open. Having high porosity hair can easily receive moisture, but it is hard for the moisture to stay inside. Medium, also known as normal porosity, has cuticles that are evenly spread out and open. This helps moisture to be received easily, and it is also easy to retain moisture. Low porosity has cuticles that are tightly packed on top of one another, making the surface mostly close. It is hard to get moisture into the hair strand; however, once moisture is in, it is easy to retain that moisture. Some people will notice that they have characteristics of more than one type and that’s totally fine! Generally, if you look at porosity like a scale, you will see that you generally fall towards one side of the scale verses the other.


Why is it Important?


Okay, you’re probably thinking “Why is it important to know my porosity?!” The main reason is that you can use this information to find products that will ACTUALLY work with your hair. Secondly, moisturized hair equals healthy hair and if you do not know how to get moisture into your hair strands and how to retain that moisture, your hair is more likely to become dry and brittle, causing it to break. That’s not what we want!


Having healthy hair means that your strands can receive AND retain the moisture you feed it. Water and products must be able to pass through the cuticle to nurture the cortex. If the hair cuticles are naturally closed, the hair cannot allow moisture in. On the flip side, cuticles that are wide open allows moisture to easily escape, making the hair continuous dry and brittle. Remember, the major key to healthy hair is having moisturized hair. Knowing how your unique hair strand is constructed will help you understand how to properly add and seal moisture to your curls.