Hair porosity is, well, what it sounds like- how porous is your hair? This matters because it determines how easily your hair is able to get hydrated and if it is able to retain moisture. I’d argue that porosity is more important to know than your hair type for how your hair will react to product ingredients and the methods that will be the most effective. Porosity is going to impact a lot of where you’ll find that coveted protein/moisture balance. As a general statement, low porosity needs more moisture or and high porosity needs more protein in their regimen.
Almost all hair that grows out of your head is low porosity. If it stays that way as your hair grows is determined by a variety of factors. Genetics play a large part in this. Some hair is naturally damage resistant while others basically changes porosity from a breeze blowing their hair. Other things that impact porosity include chemical damage, heat (even just from the sun), and manipulation.
It is quite common to have low porosity hair at the top of your head and high by the ends. So you may find that some products work best if you apply them from the ears down, especially if the ends of your hair are protein loving. Much like texture, density, and curl patterns– don’t expect uniformity all over your head.
Testing Porosity
There are a few different ways to tell how porous your hair is. Lots of people suggest the float test. While that may be a great indication for some people, especially those with finer hair will struggle with this because their hair doesn’t weigh enough to break the surface tension of the water.
One way that I think is actually semi-reliable if you are sensitive enough to feel it is to run your fingers up the shaft of a piece of hair. Does it feel smooth even when going from bottom to top? Probably low porosity since the cuticle sits so flat.
There’s also the spray bottle test. On clean hair (so that hair products aren’t skewing the results), take a hair strand and spray your hair with a fine mist. If the water just sits on your hair, you’re low. If it sinks right in, you’re high. If it takes a minute and then sinks in, you’re likely medium.
The most accurate way to know? Send your hair out to get tested in a lab. These tests aren’t cheap though.
Low Porosity
This is my hair. I have not sent out my hair to get it tested in a lab, but I don’t really need to since my hair shows all the signs of it. Low porosity hair’s cuticle sits flat and has little to no damage. Low-po hair tends to be smoother, shinier, and knot less.
Since the cuticle sits more flat, it can be hard to get moisture into your hair. Heat will be one of your best tools since it opens up the cuticle and helps moisture to penetrate into the strand. Heat can be anything from a heat cap during deep conditioning to just making sure you’re using warm water to refresh. Luckily, once it gets in there, it stays hydrated well. Downside is it also takes forever to dry.
So how will this help you pick your products? Heavy products are more likely to sit on top of your hair since it can’t absorb into that tightly sealed cuticle, so heavy butters may not work for you. You’re also more likely to like products that are more moisturizing with little to no protein. Finer low-porosity hair will likely still like more protein in their products to give some structure to the thin strands as opposed to their coarser counterparts, but you won’t need as much as a fine-haired, high porosity hair type.
One of my favorite low-po hacks is I love to dirty deep condition. A lot of heavier deep conditioners can leave my hair with build up frizz almost immediately, so by using it before cleansing, I can co-wash some of those heavier ingredients off of the surface of my hair. Then I save the less buttery deep conditioners for a day that I need use it after clarifying.
Normal/Medium Porosity
I’ve seen this referred to as both normal and medium. You don’t see this talked about much because it’s literally just an in between. It can flip back and forth between the needs of high and low, but for the most part- congrats! Your hair is the easiest as far as moisture needs. You don’t have to work as hard as the low-pos to get your hair to accept moisture and you don’t have as much of a struggle to keep the moisture like high-pos.
High Porosity
High porosity hair has a cuticle that sits more open and unfortunately also knots more easily. As stated in the intro, hair can become high porosity from chemical, heat, manipulation, or just genetics. Hair gets wet easily, but since the cuticle stays more open, it also loses that moisture faster. High porosity hair will benefit from things like finishing with a cold rinse to help close the cuticle as much as it will close.
When you’re looking for products, your hair will likely be want to drink up whatever you give it. Finer hair may not be able to handle too heavy of products, but you’ll be able to handle more than someone with your fine hair that’s low porosity. Protein is going to be a regular part of your routine. Depending on how high porosity hair is, you may want at least some protein in every part of your wash day routine (wash and styling products) along with using deep conditioners with protein. Your hair can probably handle more product than you think it can, you just need to find the right ones. So if your hair still gets weighed down with thicker, buttery products, you may want to try a higher quantity of a thinner product.
Doing treatments on your hair more regularly will help you maintain your hair health. High porosity hair is more likely to get damaged further since the structure is already weakened, so take extra care and your hair can still be soft and hydrated.
Do you have a favorite hack for high porosity hair? Or one for low that I missed? Drop it in the comments below!
