Low Medium High
Take a strand of hair and slide your fingers up the shaft (toward the scalp). If you feel little bumps along the way, this means that your cuticle is lifted and that you have high porosity. If your fingers slip smoothly, then you have low porosity hair.
Essential Hair Knowledge
Porosity refers to how well your hair is able to absorb and hold moisture. It is affected by the flexible outer hair layer called the cuticle, which determines how easily moisture and oils pass in and out of your hair. For most, porosity is genetic, but it can also be affected by external factors such as exposure, heat treatments and chemical processing. Knowing your hair's porosity can help you choose the right products to keep your hair well-moisturised, supple, strong and shiny.
Hair with low porosity has a tightly bound cuticle layer with overlapping scales that lay flat. Low porosity hair does not take in moisture well when you try to wet it and is hard to process since it resists penetration of chemicals.
It is also prone to product build-up from protein-rich deep conditioning products, which can leave it feeling stiff and straw-like. Stick to protein-free, daily conditioners with humectants such as glycerine or honey. Use moderate heat with protein-free deep conditioning treatments to help open up the cuticle so it can absorb moisture better.
Hair with medium porosity often requires the least amount of maintenance. The cuticle layer is looser, allowing just the right amount of moisture to enter while preventing too much from escaping. Hair with normal porosity tends to hold styles well, and can be permed and coloured with predictable results. Over time, however, these processes can damage your hair and increase its porosity. Occasional deep conditioning treatments with protein conditioners can benefit medium porosity hair, but proteins should not be included in your daily regimen.
High porosity hair has gaps and holes in the cuticle, which let too much moisture into your hair and leave it prone to frizz and tangling in humid weather. Even simple acts such as bathing, swimming and shampooing can create more damage and breakage due to the sheer amount of moisture highly porous hair can absorb.
Because highly porous hair can also lose moisture easily, it's important to use leave-in conditioners, moisturisers and sealers. Layering these products will help your hair hold on to the moisture you're giving it. You can even follow up with a heavy hair butter to help fill the gaps in your damaged cuticles and further protect your hair from losing too much moisture.
The FLOAT Test
Take a couple of strands of hair from your comb or brush and drop them into a cup of water. Let them sit for 2-4mnutes. If your hair floats, you have low porosity. If it sinks you have high porosity. If it sits in the middle you have medium porosity.