A true statement about porosity and absorption rate is:

• A. Higher Porosity Hair Absorbs Perm Solution More Rapidly
• B. Higher Porosity Hair Absorbs More Slowly
• C. Porosity Only Affects Coloring
• D. Porosity Has No Effect

Answer: (A)

Porosity describes how easily hair accepts moisture and chemicals. When porosity is high, the cuticle scales are more open or damaged, creating gaps that let perm solution penetrate quickly. That faster penetration means the absorption rate is higher for high-porosity hair, so processing times must be monitored to prevent over-processing. In contrast, hair with low porosity has a tighter cuticle that resists entry, causing slower absorption and often longer processing. Porosity affects chemical processing as well as coloring, so it isn’t correct to say it has no effect.