What is Porosity?
Simply put, porosity is your hair's ability to absorb and retain moisture. There are three porosity types (Low, Normal, High) and each one of us falls into at least one of the three categories. Some people fall into more than one category and that's okay. Determining your hair's porosity is fairly easy as you will see below.
Porosity Levels & How to Determine Yours
Differences between porosity levels
Low porosity hair has issues with absorption, but not retention. It's harder for this hair type to become moisturized. When it's fully moisturized, it doesn't lose the moisture easily.
Normal porosity doesn't have an issue with absorption or retention. It allows moisture to penetrate the shaft without allowing it to escape afterwards.
High porosity hair only has an issue with moisture retention. This hair type is capable of absorbing moisture easily, as well as, losing it just as easy.
Porosity Test: How to find your hair's porosity
1. On freshly shampooed hair (no products in the hair) take a few strands and drop them in a cup of room temperature water.
2. Let them sit for 3-4 minutes.
3. Check the cup to see where the hair's are located (eg. floating, semi-floating, fully submerged)
4. You now know your porosity level.
Porosity Under a Microscope
Low Porosity hair's cuticles are very compact and doesn't allow moisture to easily penetrate or escape the strands. This is why it may feel as if products sit on top of the hair, rather than penetrating the shaft. Low porosity hair types may have to be washed more frequently due to excessive product build up.
Normal Porosity hair's cuticles are compact enough to retain moisture, but not too compact that they can't absorb it. This is the ideal hair type to have. Normal porosity hair requires the least amount of maintenance of the three.
High Porosity hair's cuticles are raised and allows too much moisture to be absorbed and lost. This hair type comes from chemical processing, heat damage, rough handling, etc. Highly porous hair has gaps and holes in the cuticle which allows moisture to enter and escape at almost the same rate. Heavy butters and sealants are recommended to help retain the moisture that's given to the hair.