Which type of hair generally has low porosity?

Low porosity hair typically refers to hair that has a tightly bound cuticle layer, which makes it less permeable to moisture and hair products. Curly hair is often associated with a lower porosity because the structure of curly strands tends to create overlaps in the cuticle layers. These overlaps make it more challenging for moisture to penetrate the hair shaft, leading to lower porosity.

In contrast, straight hair can have varying levels of porosity depending on its texture and treatment, but it does not specifically correlate with low porosity as clearly as curly hair does. Color-treated hair usually has a higher porosity due to the chemical processes that alter the hair structure, making it more porous. Thinning hair does not specifically indicate porosity levels; it may have a range of porosity based on individual hair health and treatments. Therefore, the association of curly hair with low porosity stands out as the most accurate choice.