What Is Hair Porosity and How Do You Test for It? 

The secret to bringing out the best of your curls is understanding the science behind them. 
hair porosity
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So you figured out your hair type, now what? Before buying any products for your curls in the hair aisle, it’s important you take a hair porosity test. By understanding the structure of your hair, whether it may be healthy, dry, or damaged, you will save countless frustrating hours (and not to mention some cash). Now you might be thinking, What is hair porosity? To put it simply, it’s your hair’s ability to absorb and retain moisture. Your hair cuticles may be craving hydration, but you’re feeding it protein. Or vice versa. 

It’s complicated, we know. That’s why we reached out to curl experts Ona Diaz-Santin (also known as the Hair Saint), who is the CEO of 5 Salon Spa, and Pekela Riley, an Ulta Beauty pro team member and founder of True and Pure Texture, to help narrow down the dos and don’ts for the three types of hair porosities—high, medium, and low—along with the product recommendations they swear by for each.

How to Do a Hair Porosity Test

The most effective way to determine your hair’s porosity is with a strand test, also known as a float test. Take a strand of clean hair (this can also be from your hairbrush), and place it in a glass of water. Riley can’t emphasize enough the importance of a clean hair strand. “Any product buildup left on your hair will not measure the results correctly.” If your hair sinks to the bottom of the glass right away, you have high-porosity hair. If the strand floats at the top, you have low-porosity hair. And if your hair floats somewhere in the middle? You've got medium-porosity hair.

You might see similar results in your shower. Ever notice how long (or not) it takes your hair to get completely drenched? Do your curls immediately absorb the water? Or does it take your curly hair a while, even fully under the shower stream, before it becomes soaking wet? Depending on your hair’s porosity level, your hair cuticles may be tighter or looser. Keep reading to learn more about each porosity level and what your hair might be trying to telling you. 

Low-Porosity Hair

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If you have low porosity hair, just like the floating strand at the top of the water glass, it means your curls experience difficulties absorbing moisture. This is said to be true for not only water but also oils, gels, and creams. Diaz-Santin describes these cuticles as tightly bound, which makes it hard for anything to penetrate inside with ease. Your hair more often than not looks shiny and slick—similar to the cuticles themselves. Since product absorption isn’t easy for low-porosity hair, you may experience product buildup and grease, as products are sitting on top of the cuticle instead of penetrating the hair shaft.

“Try applying hair products in the shower before stepping out to allow for better absorption,” Riley advises. “I also recommend using steam or heat for deep-conditioning treatments regularly since heat allows the cuticle to raise.”

Bumble and Bumble Curl Butter Mask

Bumble and Bumble

tgin Miracle RepaiRx Deep Hydrating Hair Mask


Flora & Curl Flower Garden Hair Butter Concentrate

Flora & Curl

Naturalicious Heavenly Hydration Grapeseed Hair Mist


Medium-Porosity Hair

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“Maintenance isn’t as complicated for medium-porosity hair,” says Riley. Your hair can absorb and retain moisture well, as the structure of the hair cuticle is not too tight, like low-porosity hair, and not too spaced out and open, like high-porosity hair. Although you see little to no immediate damage when coloring or applying heat to your curls, over time, just as with any hair type, damage and breakage can occur.

Product recommendations depend on how high or low your hair leans (or floats in a glass of water). If your strand floats closer to the top of the glass, Diaz-Santin advises protein-rich products. If your strand of hair floats closer to the bottom, go with a buttery, oily product like Bumble and Bumble Hairdresser’s Invisible Oil Mask.

Ouidad Moisture Lock Leave-In Conditioner


Bumble and Bumble Hairdresser’s Invisible Oil Mask

Bumble and Bumble

Carol’s Daughter Monoi Leave-In Conditioner

Carol's Daughter

Curlsmith Moisture Memory Reactivator


High-Porosity Hair

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High-porosity hair is super absorbent, so much so that you’ve probably found it’s hard for your curls to retain moisture, says Riley. With your widely spaced and raised cuticles (which often equates to tangles, breakage, and frizz), the benefits of hydrating products don’t tend to last long. You can chalk this up to continuous heat styling or coloring, but simple genetics may also be the cause. 

With high-porosity hair, the best thing to feed your curls is protein and a good hair oil. Why protein over hydration, you ask? Protein contains properties that aid in strengthening and reviving otherwise brittle hair cuticles. Following that with a great oil will help seal the gaps in your hair’s cuticles and provide a protective barrier from further damaging elements. Here are some of our curly experts’ favorites for high-porosity hair. 

Kreyòl Essence Haitian Black Castor Oil

Kreyòl Essence

Fekkai Brilliant Gloss Multi-Tasker Perfecting Creme


Bumble and Bumble Hairdresser’s Invisible Oil Hot Oil Concentrate

Bumble and Bumble

Pattern Jojoba Oil Hair Serum


Talia Gutierrez is the beauty assistant at Glamour, Allure, and Vogue. Follow her on Instagram @taliamichelee.