Everything you Need to Know about Hair Porosity

Everything you Need to Know about Hair Porosity

Hair porosity is the hair’s ability to absorb and retain water. There are 3 main types of hair porosity and your type is often dictated by your genetics. How porous your hair is starts with the hair cuticles and how open and closed they are determines your type. Understanding your hair porosity is essential to your haircare routine as you’ll want to feed your curls exactly what they need so you can enjoy healthy hair.


What is Hair Porosity

Hair porosity is determined by how open or closed the hair cuticles are. Hair cuticles are little scales that cover the external layer of the hair’s surface and control how much moisture can penetrate into the hair shaft. These scales can be more open or closed depending on a series of factors which include genetics, environmental agents, and hair damage.


Genetics is the main element that factors into what type of hair porosity someone has. Depending on your genes, you can be born with naturally higher or lower porosity hair. Because of its dry nature, curly hair in its virgin state is naturally higher in porosity than straight hair, and the curlier it is the higher porosity tends to be.

However, hair porosity is not final. Porosity changes any time the hair structure is altered – in other words, damaged. The more damaged your hair is, the higher porosity it will be, as damage lifts the hair cuticles. There are several factors that can permanently affect your hair’s porosity, some more drastically than others:

  • Excessive exposure to the sun, UVA and UVB rays
  • Air pollution
  • Dying your hair
  • Frequent use of heat styling (flat irons, hair curlers etc.)
  • Bleaching your hair

The above factors may require protein-rich products from our Strength Recipes to help repair some of the damage.


The American Board of Certified Hair Colorists categorises porosity into 5 different levels:

  1. Grade 1 Porosity: virgin hair that has been exposed to little or no environmental damage. This is very hard to find, and it’s more common in straight hair types. The cuticles on this hair are extremely tight, and they don’t allow moisture in or out. The hair feels smooth and looks very shiny with no product on.
  2. Grade 2 Porosity: this is still natural virgin hair, but it’s been exposed to some type of environmental damage. This applies to most people with virgin hair. The hair is still very healthy and easy to manage. It doesn’t tangle too much and looks shiny. The cuticles are still very tight and it’s hard to make the moisture penetrate in the hair shaft.
  3. Grade 3 Porosity: this is hair that’s been altered and coloured up to 5 shades lighter. Since it’s been through some chemical processing, it has some level of damage. The cuticles are halfway open, they allow moisture in but they also start losing it more easily.
  4. Grade 4 Porosity: this is hair that’s been bleached and lightened up to 7 shades lighter. This hair is quite compromised, as it’s been through a lot of chemical processing, so it will need additional care and attention. The cuticles here are open, so it needs lots of moisture because it also loses it very easily.
  5. Grade 5 Porosity: this hair is too compromised to save. There is no cuticle left on the strands, you only see the inner part of the hair (called medulla). Because there is no structure left, the hair will feel gummy to the touch and break whenever you run your fingers through it. The only way to fix level 5 porosity hair is by cutting it.

Porosity grades are universally grouped in 3 categories: grade 1 and 2 are known as low porosity, grade 3 is known as medium porosity and grade 4 and 5 are known as high porosity. The higher the porosity grade, the more protein-rich products you should incorporate in your routine to strengthen the cuticle structure and allow it to keep moisture inside the hair shaft.

Hair Porosity Guide


There are several tests available to identify one’s porosity.

The first is the glass of water test. Simply take a clean, product-free strand of loose hair and put it in a glass of water. If the hair floats at the top then it is low porosity, if it sinks slowly or settles in the middle it is medium/normal porosity, and if it sinks straight to the bottom then it is high porosity.

The other way to test is to simply run your fingers down a hair strand to feel its texture. If the hair feels smooth then it is low porosity, if it is rough or bumpy then it is high porosity.


The most effective test is without doubt the spray test. Make sure to start with clean, product-free hair (no leave-in products, neither conditioners nor stylers). Spray some water on a strand of hair and observe its behavior:

  • If the water forms lots of little droplets on the hair surface without sinking in, you have LOW POROSITY.
  • If the water forms some little droplets, but sinks in easily afterwards, you have MEDIUM POROSITY.
  • If the water instantly sinks into the hair, you have HIGH POROSITY.

Testing Hair Porosity


Different porosities require different care, and making sure they get it is the secret to enviable curls. It is possible to have different levels of porosity within your curly hair, especially if you are transitioning to natural hair. You may find that your roots are low or medium porosity, whilst your ends that have seen straighteners, bleach and more may be high porosity. If this is the case you should always treat your hair for the highest level of porosity it has, as that's the area that requires more care and attention. Ideally, you should be looking to achieve and maintain the perfect protein moisture balance every wash day.


We are a gourmet haircare brand that specialises in curly, wavy, and coily hair. We created our range of curl loving products in partnership with trichologists, curly hair stylists, and curly influencers. We combine kitchen cupboard staple with yummy natural ingredients to create formulas, treatments, conditioners, & stylers that really work for all your curly needs.

Sharley Viola
Curlsmith’s Lead Educator

Textured Hair Specialist with a vast amount of experience delivering education both nationally and internationally. A self-confessed product junkie committed to spreading her wealth of knowledge amongst the curly hair community and beyond.

Sharley Viola
Curlsmith’s Lead Educator

Textured Hair Specialist with a vast amount of experience delivering education both nationally and internationally. A self-confessed product junkie committed to spreading her wealth of knowledge amongst the curly hair community and beyond.