What to Know About High Porosity Hair

Medically Reviewed by Jabeen Begum, MD on November 25, 2022
4 min read

There are many ways we can categorize our hair: curly or straight, thick or thin, fine or coarse. One aspect that’s important to your hair health but not talked about as often is your hair’s porosity. Hair porosity can affect the way your hair looks and feels and its overall health. Having high porosity hair can lead to damage, but proper care can give you happy and healthy hair.

Hair porosity refers to how much or how little water your hair absorbs and retains. Your hair’s porosity depends on the integrity of your hair cuticle.

Each hair shaft is made up of two or three layers:

  • Medulla: In the center of some hair shafts is spongy tissue called the medulla. Fine hair is less likely to have a medulla than coarse hair.
  • Cortex: The cortex of your hair is made of proteins that allow the hair shaft to stretch. This is also the layer that holds your hair color.
  • Cuticle: The cuticle is the outer layer of hair. It’s made of flattened cells that overlap each other like tiles on a roof. When these cells are lying down flat, the hair is smooth. Cells that are sticking up may allow moisture loss and damage. 

Hair porosity can be impacted by your genetics or your hair grooming routine. It’s possible to have hair strands of multiple porosity levels on your head and even have different levels of porosity within a single strand of hair.

Hair with “normal” levels of porosity will absorb 75% of the maximum water possible within four minutes. People with normal porosity hair usually have an easy time getting their hair to hold bleach, hair dye, or relaxer, and the results tend to be predictable.

Low porosity hair has cuticles with skin cells that lay flat and are reinforced, making it more difficult for water or chemical treatments to penetrate into the cortex. People with low porosity hair may notice that:

  • It takes a long time for their hair to get wet and to dry.
  • Products build up on the surface of the hair instead of being absorbed by the hair.
  • Protein treatments make their hair feel stiff.
  • Chemical treatments don’t work as well as they expect.

For people with high porosity hair, the hair cuticle is compromised in some way. Often, this may simply be caused by the texture of your hair. The twists in curly or coiled hair can disrupt the layers of cells. The more curly or coiled the hair fibers are, the more disrupted the cuticle may be. Other things that can damage your hair cuticle and lead to porous hair include chemical treatments, ultraviolet (UV) radiation, and even basic grooming like brushing and combing your hair.

High porosity hair characteristics may include:

  • Absorbs water quickly and dries quickly
  • Feels dry
  • Looks frizzy
  • Breaks easily

If you’re unsure which type of hair you have, there are a few experiments you can try at home to get a general idea of whether you have low, average, or high porosity hair. Remember that different hairs on your head can have different levels of porosity.

Float test. Take a clean strand of hair and drop it into a glass or bowl of room-temperature water. A clear container works best so you can observe the hair. For a better idea of your overall hair porosity, try taking strands from multiple places around your head. The amount of time it takes the hair to sink will give you an idea of how porous your hair is:

  • High porosity hair will sink right away.
  • Average porosity hair may float for a minute or two before starting to sink.
  • Low porosity hair will float for some time before slowly sinking.

Spray test. This test is harder to observe but still can give you an idea of how porous your hair is. Spray water on clean, dry hair. If your hair is highly porous, it will absorb the water right away. Low porosity hair may have visible beads of water and take a long time to dry.

Laboratories also perform more technical low and high hair porosity tests. These include: 

  • Dynamic vapor sorption: Hair weight is measured and recorded as humidity increases and decreases.
  • Fiber swelling: The dimensions of hair are measured as the hair is exposed to water.
  • Gas adsorption and pore size analysis: Scientists expose hair samples to nitrogen, then look to see how many pores the hair has and where on the hair they are.

The most pressing concerns for high porosity hair are damage and loss of moisture.

Some people with textured hair use a technique to seal in hydration called the LOC method, which stands for leave-in conditioner, oil, and cream.

  • Leave-in conditioner is applied to wet hair and isn’t rinsed until the next time you wash your hair. Choose a lightweight product meant for your hair texture.
  • Oils are a great method for sealing in moisture, but remember that a little goes a long way. You can purchase hair oils or use something like avocado oil. Polyunsaturated oils seem to work best for hair.
  • Creams are available for a wide variety of hair types. Choose the one that works best for you. 

People with high-porosity hair should try to limit things like heat and chemical treatments. These can further damage cuticles, making it even harder for your hair to retain moisture and nutrients. 

If you live in an area with high humidity, avoid products with humectants. Humectants are products that draw in moisture from the environment. In high-humidity climates, this can lead to hair becoming poofy and frizzy. 

Protein treatments can help repair the hair cuticle and reduce hair porosity. Hair is made from a protein called keratin. Using a protein treatment can help fill in the areas in your cuticle that have damaged cells. This can help smooth the cuticle down and create a protective coat over the hair shaft.