What does the term "porosity" refer to in hair care?

Porosity in hair care refers to the hair's ability to absorb and hold moisture. This characteristic is crucial because it affects how well hair can retain hydration, which is vital for maintaining its health and appearance. Hair with high porosity can absorb moisture easily but may also lose it just as quickly, making it more prone to damage and frizz. Conversely, hair with low porosity has a tighter cuticle layer, making it more resistant to moisture absorption. Understanding porosity helps cosmetologists select appropriate treatments and products for hair care, addressing moisture retention issues effectively.

The other choices address different attributes of hair. Strength pertains to the hair's resilience to damage and breakage but does not directly relate to moisture absorption. Hair color refers to the pigment present in the hair strands, influencing aesthetic appearance but not its moisture capacity. Sheen is related to the shine or luster of the hair, which can be affected by moisture levels and product use, but again, it is not a direct measure of how well hair can absorb moisture.