Ask someone to describe their hair and the first two things they’ll talk about are its thickness and texture. However, there’s another descriptive feature of your hair worth noting when colouring or styling it—hair porosity. Simply put, hair porosity is your “hair’s ability to absorb and retain moisture,” explains Chicago-based celebrity hairstylist Anthony Cristiano. “The porosity of your hair affects how well moisture and oils pass in and out of the outermost layer of the hair called the cuticle,” adds Los Angeles-based Mark Townsend, celebrity hairstylist and Collective Laboratories advisor. “For hair to stay healthy and hydrated, water and moisturising products need to penetrate the cuticle to get inside the hair.” This ability goes to affect the overall texture of your hair and impacts the choices you make when colouring, styling and even caring for it. We deep dive into everything there is to know about hair porosity and why it's an important aspect when hairstyling and care are in question.
The hair porosity test
Understanding your hair porosity isn’t rocket science—all it takes is a few loose strands of hair and a float test. “Begin with a strand of hair and let it sit in a bowl with warm water for two-four minutes. If your strand floats to the top, you have low porosity. If it sinks right to the bottom, your hair has high porosity,” explains Cristiano, who’s worked with the likes of Gigi Hadid and Mariah Carey. Essentially, you want your hair porosity to be at a medium or normal level where your hair retains just enough moisture for it to be healthy. Too much and your hair will be on the drier side, too little and your hair will be dull and lifeless. “If the cuticles are too tight or close together it is not easy for water and oils to penetrate the hair, making it harder to get the moisture it needs which is low porosity hair,” says Townsend. “If the cuticles are open or too widely spaced, the hair will have a harder time retaining moisture and staying hydrated, which is high porosity hair.”
How hair porosity affects your hair colour and style
Contrary to popular belief, you can’t simply book an appointment and go in for a new hair colour at whim. There are multiple reasons why most hairstylists recommend a consultation prior to your actual colour job. This consultation involves checking hair for its texture, natural or current colour, porosity and overall health to decide on the best colour treatment for you. “If your strands are too porous, the colour will further weaken your hair because the colour is absorbed into the hair more easily, so this must be taken into consideration,” advises Cristiano. It’s essential to factor in your hair’s health when deciding on how you colour it and even how light you decide to go—the lighter you go, the drier your hair will naturally get. Porosity is checked to also ensure that your hair colourist uses the necessary conditioning treatments to keep your hair healthy while they colour it.
Believe us (and the experts) when we say this, but porosity really does affect the way your hair behaves when you’re styling it. “Low porosity hair has a tendency to repel moisture which can be challenging to process and style,” explains Townsend. “Products sit on top of low porosity hair instead of penetrating inside so the product can quickly build up leaving the hair dull and flat. Low porosity hair also tends to take longer to dry.” He recommends using a clarifying shampoo like the Collective Laboratories Detoxifying Shampoo to deep clean your hair and reduce buildup. “High porosity hair tends to look and feel dry or frizzy and will absorb product very quickly so be sure to use a heat protectant spray when styling.
How to improve your hair porosity
“It is important to understand the porosity of hair because it guides you to use the most appropriate hair product that is most suitable to your hair type,” says Cristiano. If your hair porosity is high, use a protein-free daily conditioner. “Too much protein in hair products can make the hair brittle and may cause breakage.” Also, if your hair porosity is on the higher end, “you want to reduce and reverse damage to the cuticle so heavier conditioners are a must and you’ll want to seal the cuticle as much as possible,” says Townsend. “Select products that will hydrate your hair, such as leave-in conditioners, hydrating sprays and argan oils,” adds Cristiano. The former even recommends layering products to intensity hydration.
If it is low, “choose products that will add volume such as hairspray, mousses, and texturizing sprays,” suggests Cristiano. Townsend recommends using ingredients that can easily penetrate the cuticle if your hair has low porosity.
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