What is the rarest hair porosity?

There is no such thing as a rare hair porosity. Hair porosity is a measure of how easily hair can absorb and retain moisture, and it can vary from low to high. All three types of hair porosity (low, medium, and high) are common and can occur in individuals of any ethnicity and hair type. The porosity of an individual's hair is determined by the shape and condition of the hair cuticle, which can be influenced by genetics, environmental factors, and hair care practices.