Permanent hair color is considered penetrating because it has the ability to?

• A. Penetrate the cortex
• B. Remove pigment
• C. Absorb into the cuticle
• D. Change melanin

Answer: (C)

Permanent hair color is penetrating because its color molecules are able to pass through the outer cuticle and reach the cortex, where they interact with the hair’s natural pigment to produce lasting color. The cortex is where pigment resides and where the color-forming reactions occur, so penetration into this layer is essential for a durable result. If the molecules stayed in the cuticle, the color would be superficial and less durable, which is characteristic of non-penetrating or semi-permanent colors. The action isn’t about removing pigment or merely changing melanin itself; it’s about depositing new color inside the cortex through diffusion through the cuticle.