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Understanding Hair Porosity and How it Affects Hair Care

Hair porosity can be one of the more confusing concepts in hair care, but it’s simply how well your hair absorbs and retains oil and moisture. Hair porosity is typically divided into three broad categories: low porosity hair, medium and high. So, wondering what porosity you have, what affects it and how can you use this knowledge to treat your hair? Keep reading—we’re diving deep into all things hair care.

What is Hair Porosity?

Hair porosity definition, check. Now, to better understand its concept, let’s explore the structure of your hair. Each strand has three layers. The cuticle is your hair’s outer layer, a tough protective coat made up of smaller, overlapping pieces (think shingles on a roof). The thickest layer, the cortex, contains fibrous proteins and the pigment that gives your hair its color. Then there’s the medulla. It’s the soft, innermost part of the hair shaft, and it’s also the most fragile.

For healthy and hydrated hair, it's crucial that the cuticle allows water, oils and other moisturizing products to pass through to the cortex. However, if the cuticles are too close together, it’s harder for water and oils to penetrate the hair and deliver that moisture. On the other hand, if the cuticles are too widely spaced, it’s harder to retain moisture.

What Determines Hair Porosity?

Naturally, genetics play a large role in how your hair absorbs and retains moisture. If low porosity hair runs in your family, you’ll likely have it, too. But genetics aren’t the only determining factor. Blow drying, bleaching and straightening your hair all can damage your follicles over time. Over washing and using harsh products can also harm your hair. In addition, excessive ultraviolet rays can increase hair’s porosity. As a result, the cuticles can become raised and open, making it harder to retain moisture.

How Do I Know What My Hair Porosity Is?

Curious to know your hair’s porosity? There are two hair porosity tests that can help you determine it.

The Float Test

The more common of the two is the float test. Start by removing a couple of hair strands from your comb or brush. Then drop them into a glass of water. After letting them sit for 2-4 minutes, take a look at how the strands respond to the water. If your hair floats, you have low porosity. If it sinks, you have high porosity.

The Slip ‘N Slide Test

You can also take a strand of hair and slide your fingers up the shaft toward the scalp. Feel bumps along the way? This means your cuticle is lifted, a sign of high porosity. If your fingers slip smoothly, you have low porosity hair.

Low Porosity Hair Characteristics

Each porosity has distinct characteristics and ways to recognize it. Let’s explore each, starting with low. Low porosity hair has cuticles that are tightly packed and close together. Together they act as a guard, making it hard for moisture to penetrate the hair shaft. You may have low porosity hair if hair products don’t absorb easily and tend to just sit on your hair. You may also find it’s hard for water to saturate your hair on wash day and that it takes a long time to air dry.

Medium Porosity Hair Characteristics

Medium, or normal, porosity hair has cuticles that are neither too close nor too open. They’re just right, allowing moisture to flow in and also helping to retain it for longer. If your hair is easy to style and holds a style well, you may have medium porosity hair. Other indicators include taking color well, hair appearing healthy and shiny, and not taking too long for your hair to air dry. However, keep in mind that heat damage and chemical processes can change normal porosity hair over time.

Higher Porosity Hair Characteristics

Whether by genetics or hair damage, high porosity hair absorbs moisture easily, but doesn't retain it for long. This is because the cuticles of the hair have spaces between them. One way to tell that your hair porosity is high is if your hair absorbs moisturizing products quickly, yet still tends to be dry, frizzy and easily breakable. That's because as easily as moisture enters the strands, it comes back out. Your hair may also be high porosity if it air dries quickly.

Hair Care Based on Hair Porosity

Learning your hair’s porosity can help you take better care of it, including the products you use and the way you style it. If your hair’s porosity is high or low due to genetics, you likely can’t change it. However, there are ways to make your hair healthier, more manageable and easier to style.

For Low Porosity Hair

Stick with protein-free conditioners. They tend to absorb more easily into your hair and are less likely to cause product buildup. Also, you’ll want to apply conditioner to your hair while it’s still wet. Diluting the conditioner this way helps it absorb easily. Another tip is to apply heat when conditioning your hair. Try using a steamer, heat cap or hooded dryer. Don’t have one? Placing a shower cap over your hair once you’ve applied a conditioner also does the trick.

For High Porosity Hair

To help moisturize your hair, check the labels for ingredients like butters and oils when choosing your shampoo and conditioner. Then, to help your hair maintain moisture, add leave-in conditioners and sealers to your hair care toolbox. And before blow drying or using other hot tools, start with a heat-protectant product. This helps protect the hair and ward off heat damage. Finally, avoid using hot water on wash day. Instead, opt for a lukewarm temperature.

Understand Hair Porosity for Healthier Hair

While hair porosity may not be a term you hear often, knowing how porous hair is, can help you better manage, treat and care for your tresses so you have stronger, healthier hair.