What is Hair Porosity?

From the moment you roll out of bed in the morning, your natural hair makes its uniqueness known—whether it’s curly, coily, straight, or inventing new shapes altogether. It’s fair to say such one-of-a-kind strands demand customized care and knowing your hair type can certainly lead you to some solutions. 

But one factor of your hair you might be less familiar with is its porosity. So, what is hair porosity? Your hair porosity determines how much moisture each follicle can absorb and retain—think conditioners, oils, and even water.1 Too low porosity and your hair may lack volume. Too high, and you could be noticing frizz even with conditioner. 

Types of hair porosity

To understand hair porosity and how it affects your strands, it can help to first take a look at the structure of a single hair follicle. There are three layers to every strand:

• The cuticle
• The cortex
• The medulla

The outermost layer, the hair cuticle, is what determines porosity. It serves as the barrier between the inner layers of a strand of hair and everything your hair comes into contact with. It’s composed of smaller cuticles, called keratinocytes, that overlap one another.

Hair cuticle spacing varies from close to wide. Too close together, and product will have a hard time passing through. Too wide, and the product will quickly leave the hair. But a hair type with balanced porosity will leave just enough space for moisture to enter and for the hair to retain it throughout the day.

What is high porosity hair? With high porosity hair, hair cuticles are widely spaced out, making the outermost layer of each hair more permeable.1 Its porous surface can make moisture retention a challenge (you heard that right—if your hair’s always a little drier than you’d like, it might be inherent).

You may have highly porous hair if you notice that:

• Your hair quickly dries after the shower without a hair dryer
• Your hair tends to be frizzy and dry
• Your hair is prone to breakage
• Your hair quickly loses styles such as curls or waves
• Your hair is quick to absorb moisturizing products such as oils and conditioners

Balanced Characteristics

Hair with balanced porosity is a happy medium between low and high porosity.  The cuticles of each strand are capable of both absorbing and retaining moisture.

You may have balanced porosity hair if you notice that:

• Your hair doesn’t take long to air dry, but doesn’t dry very quickly either
• Your hair tends to shine naturally
• Your hair is strong and doesn’t easily experience breakage
• Your hair easily holds styles throughout the day

Although balanced porosity hair is a pro at keeping and retaining moisture, you can quickly knock it off balance through the overuse of hot tools such as blow dryers and straighteners or harsh products.

Low porosity characteristics

What is low hair porosity? With low porosity hair, your hair’s cuticles are so closely layered that they seemingly pile on top of each other. This leaves little space for moisture, from water to deep conditioning treatments, to enter the hair shaft. You’ll need to be a bit more patient with this hair type.

You may have low porosity hair if you notice that:

• Your hair doesn’t easily absorb moisturizing products
• Your hair needs a long time to air dry
• Your hair requires some extra time in the shower for the water to thoroughly wet it
• Your hair shows signs of product buildup
• Your hair is prone to dryness or frizziness

What affects hair porosity?

Just like hair texture, hair porosity is largely determined by genetics. This means that if high porosity hair is common in your family, you are more likely to have high porosity hair as well.

However, your hair type can also sometimes change as a result of damage. This may include:

• Overuse of treatments such as bleaching
• Sun overexposure
• Chlorine damage
• Overuse of hot tools without a protectant
• pH imbalances

Fortunately, high or low porosity hair is not untreatable—whatever the cause. Along with some healthy hair habits, you can avoid setting your hair porosity off-balance by being cautious of treatments like:

• Regularly blow drying with high heat
• Using other hot tools without heat protectants
• Frequently using harsh chemical treatments, such as bleach or relaxers

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