Heather Kennett explains hair porosity and how to identify whether yours is low or high by testing how quickly it absorbs water. Low porosity needs the squish-to-condish method to force moisture in; high porosity requires sealing with leave-in conditioner or oil to lock moisture in. Porosity varies across your head, so different sections need different care.
The porosity of hair is quite a huge topic. So you have high porosity hair and low porosity hair as indicated at the beginning. We do recommend revisiting these hair tests, but for a snapshot in time. Your hair porosity is how well your hair accepts water and oils, but also how well it releases those. So high porosity hair absorbs water and oils and products quickly, but also will release them fairly quickly. And therefore you need to bear that in mind when you're applying your products and the different products you're choosing to use for high porosity hair, the same for low porosity hair. Low porosity hair doesn't absorb water easily, so you might need to be squelching and squishing the products and water into your hair. You might need to adapt squish to condition to get the moisture in. Because your cuticle is quite tight with low porosity hair, it's running off and you need to squish into your hair to get the moisture into your hair. So key indicators of low porosity hair would be if your hair initially repels water and takes some time to soak it up. Key indicators of high porosity hair is hair that absorbs water and products really quickly, but likewise, five, ten minutes later could be bone dry and letting all of that moisture back out. So there are things you can do to help. High porosity hair can be affected, not always can be genetic, but can be affected by previous heat styling, by chemical adaptions to the hair and things that you've done over a period of time, damaging the cuticles, lifting the cuticles, and therefore they're expelling the moisture quite quickly. So if you have low porosity hair, as I mentioned, you need to squish and work the water and products into your hair. If you have high porosity hair and it's accepting things quickly, but again releasing them, you may want to emulsify some. Seal it with your leave in conditioner, just one or two drops, or use one or two drops at the end of the process of your hair styling and drying to seal that moisture in. Again, gel costs may be a way forward for you with high porosity hair. This again may change along your journey. And you also can have more than one porosity across your hair. So as an example, my hair across the top section is much more high porosity than underneath, which is a low porosity. So I really have to work the water and products into the underneath of my hair.
