Overly porous hair is usually caused by which factor?

• A. Underprocessing
• B. Sun exposure
• C. Overprocessing
• D. Heat styling

Answer: (C)

Porosity reflects how open the hair cuticle is and how easily moisture and chemicals can move in and out. When hair is overprocessed chemically, the processing time or strength is excessive, which lifts or strips away cuticle scales and disrupts the bonds in the cortex. This damage creates numerous channels and gaps, making the hair highly porous. As a result, moisture and color solutions rush in and out, leading to dryness, frizz, and uneven color absorption.

Underprocessing, by contrast, leaves the hair less altered, so the cuticle remains relatively intact and porosity isn’t dramatically increased. Sun exposure and heat styling can contribute to surface wear and dryness, but they’re not the primary cause of the pronounced porosity seen with overprocessing.