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How to Figure Out Your Hair Porosity (And Why It Matters)

When figuring out a new hair regime, it's easy to get hung up on the more external aspects of what your hair might need, such as color, style and scalp dryness. But if you look a little closer, there's a more scientific way to understand how to best care for your hair and determine its moisture needs: the hair porosity test.

What Is Hair Porosity and Why Does it Matter?

If you've spend any time going down a curly girl rabbit hole on Instagram, you've heard the term, but what exactly is hair porosity? On a basic level, it's a reflection of your hair's ability to absorb and retain moisture. Hair porosity determines how easily products are able to penetrate the hair follicle through the protective barrier of the cuticle layer, which is a flexible barrier that protects the hair strand's interior from damage. While your hair porosity level is largely determined by genetics, it can also be influenced by outside factors like sun exposure and the use of heat treatments and hair dyes. Even activities like swimming in a chlorine treated pool or drying your hair can increase porosity levels and lead to high porosity hair.

Understanding your hair porosity is an easy way to determine the best products to support your hair wellness. It's particularly important for those of us with curly or natural hair to understand our porosity levels. Curly hair often has a high porosity, and improperly moisturized strands can lead to a loss of curl definition, as well as increased breakage. Different hair porosity types require different amounts of moisture and protein for optimum strength and shine. Understanding your porous hair is the key to developing an individualized hair care regime that results in healthy hair.

Also: Why You Should Pay Close Attention to Your Scalp

How to Determine Hair Porosity With the Glass of Water Test

Although hair porosity isn't visible to the naked eye, you won't need to break out the microscope to understand your individual hair types either. In fact, the only tool you'll need to perform a hair porosity test is a simple glass of water. With this method, sometimes called the shedding test or the strand test, you can quickly test your hair porosity by taking a strand of your hair and letting it float it in a glass of water. Make sure your hair is clean and free of products before you perform this test. This is important as oily hair will float no matter what type of hair it is — the oil will repel water, causing it to remain at the surface of the glass giving you inaccurate test results.

Once you've put it in the water, let the hair strand sit for a few moments and observe how the strand behaves. If your strand of hair sinks to the bottom immediately, it means that it's likely highly porous. Sinking can indicate that the hair has quickly absorbed water, which has caused it to sink. Medium, or normal porosity hair, will sink slowly, or float somewhere in the middle of the glass for a few minutes before eventually sinking to the bottom. Hair with low porosity will remain floating on the surface of the water for a long time, and may never sink to the bottom of the glass.

An even easier method to test for porosity is simply wetting a clean section of your dry hair and observing how it reacts. If the water droplets sit on your hair, it can indicate a low porosity level. If the hair absorbs the water quickly through the cuticle, it's likely highly porous, as this indicates the hair's ability to retain moisture.

See: 5 Super Simple Hairstyles for Curly Hair

What Is Low Porosity Hair?

Low porosity hair has a low porosity level, and is characterized by a tightly bound outer cuticle with overlapping layers that creates a smooth texture and keeps water from penetrating the interior of the strand. If you can get out of a swimming pool with your perfect hair still intact, or it takes forever to get your hair wet in the shower, you probably have a low porosity hair type. That tight cuticle layer means your hair is resistant to absorbing moisture and repels water, no matter how hard you try to get it wet. Low porosity hair also resists the absorption of hair care products, which can make it difficult to deep condition to the hair follicle's core.

Also: How to Protect Curly Hair While Sleeping

How to Care for Low Porosity Hair

To maintain healthy hair, those with low porosity hair should seek out:

What Is Medium Porosity Hair?

Hair with a medium, or normal porosity level, is hair on easy mode, with no real hard line product restrictions — lucky you! Medium porosity hair absorbs moisture easily, thanks to a looser cuticle layer which prevents too much water from escaping but is still open enough to allow moisture to penetrate the barrier of the cuticle. However, while normal porosity hair is easy to deal with, you still need to maintain a consistent product rotation to ensure your hair retains its healthy moisture balance. Over time normal porosity hair can become damaged, disrupting the hair's natural growth patterns and increasing how porous hair is. This means you can move from medium to high porosity hair texture without even noticing.

How to Care for Medium Porosity Hair

Keep your medium porosity hair healthy by maintaining your natural balance using tools like:

  • Daily application of light moisturizers and mildly cleansing shampoo
  • Use a deep conditioning treatment (try once a week to start) to encourage moisture retention and promote hair strength
  • Highly emollient products like easily absorbed moisturizing oils
  • Products that support your hair's health like biotin gummies or your favorite multivitamin

Learn: What Is Hygral Fatigue? Tips for Curly Girls

What Is High Porosity Hair?

There are a few different factors that can contribute to having hair with high porosity. You could have a naturally highly porous hair determined by your genetics, but high porosity hair can also be caused by external factors such as environmental damage, chemical processing or just general rough treatment. Even simple actions such as shampooing too frequently or towel drying too vigorously can result in high porosity hair. Activities such as swimming or bathing can result in increased strand breakage for high porosity hair, as the cuticle absorbs more moisture than it is able to retain.

Highly porous hair has a cuticle layer with gaps or holes, meaning moisture is easily absorbed but just as easily lost, leaving hair dry and prone to damage as products evaporate before they're able to do their job. Curly hair with high porosity is often prone to frizzing and tangles in humid weather, and can have a flat or matte appearance.

How to Care for High Porosity Hair

Improve the texture of your high porosity hair by encouraging moisture retention and structural support with the use of products like:

  • Protein-rich serums like the GRO+ Advanced Hair Serum Kit
  • Deep conditioning products to lock in moisture close to the shaft
  • Moisturizing conditioners
  • Styling products like gels or oils to lock in moisture and prevent your hair from absorbing more water than it can handle, especially key for humid areas

Also: Does Your Hair Hurt? Here's Why

Your Hair Porosity Can Change

Whatever your hair porosity level is, remember that our hair's needs and structure evolves over time. When introducing a new product, check your hair's porosity level to make sure it's still appropriate for you. Your hair needs change throughout your life, and changes caused by the hormonal shifts of adolescence, postpartum and the normal results of healthy aging can cause your hair to change in porosity levels, as the follicle tightens or expands. So whatever product solution you find, don't be afraid to switch it up occasionally! Your hair porosity is always evolving, just like you.


Photo credit: Tomaz Barcellos/Pexels

Disclaimer: Information in this article is intended for general informational and entertainment purposes only. It is not intended to constitute medical advice, diagnosis, or treatment. Always seek professional medical advice from your physician.