Porosity refers to how prone your hair is to water: basically, to what diploma the outer layer of the strand takes in or retains out water.

 “The outer layer of the hair strand known as the cuticle layer. The cuticle layer is manufactured from little tiny cuticles that lie barely over each other,” hairstylist explains. Consider this as you’d a shingles on a roof—and your porosity comes from how tightly these shingles are packed collectively.

“Hair porosity describes how the hair’s cuticle absorbs and holds on to moisture in its pores—therefore, the time period porosity,” says hairstylist , co-founder of hair care model . So when your hair excessive on the porosity spectrum, it means it is very porous, and thus the cuticles are extra sparse than they’re dense, so it is in a position to take in numerous water. 

In distinction, you’ll be able to have : “When somebody has low porosity hair, the hair tends to have hassle absorbing moisture as a result of the hair is proof against water,” says Malary. “When the hair has low porosity, the cuticles are packed so tightly onto one another, it makes it very troublesome for moisture or water to penetrate the strand.”