What does the term 'porosity' refer to in hair?

Porosity in hair refers to the ability of the hair to absorb liquids, making it a crucial aspect of hair care and chemical treatments. It is determined by the condition of the hair cuticle, which is the outermost layer of the hair. When the cuticle is well-aligned and healthy, hair has low porosity, making it more resistant to absorbing products and moisture. Conversely, when the cuticle is damaged or raised, as seen in over-processed or damaged hair, the porosity is high, allowing for greater liquid absorption but potentially leading to brittleness and breakage. Understanding porosity is vital for selecting appropriate hair care products and chemical treatments, as it influences how hair reacts to moisture, color, and other hair services.

Thus, the significance of porosity in hair care cannot be overstated, as it directly impacts the health and manageability of the hair.