Porosity, you might know, refers to how susceptible your hair is to water: Essentially, to what degree the outer layer of the strand takes in or keeps out water. Each of us has different levels of porosity. Here, let’s talk specifically about low porosity hair. In contrast, you can have high porosity hair. This happens when your cuticles aren’t as dense, and thus moisture flows through the hair with ease. There is, of course, a spectrum to this: You don’t have to fall squarely in one camp or the other—in fact, you might find you’re somewhere in the middle. Hair, after all, is full of variables and possibilities.
