Lighteners utilize ingredients such as ammonia and peroxide to penetrate the cortex and:

• A. Cause Melanin to Break Down
• B. Slow the Decolorization
• C. Seal the Cuticle
• D. Remove Pigment Only from the Surface

Answer: (A)

Lighteners work by oxidizing pigment in the cortex. The alkaline mix from ammonia raises the pH and opens the hair cuticle, allowing hydrogen peroxide to penetrate deeper. Inside the cortex, the peroxide provides oxygen that oxidizes melanin, breaking it down and lightening the hair color. Since melanin resides in the cortex, the pigment change happens throughout the hair, not just on the surface. The goal isn’t to seal the cuticle or to slow the process; sealing would block penetration, and removing pigment only from the surface wouldn’t affect the pigment deeper in the fiber. Oxidation of the cortex pigment is the mechanism behind the lightening effect.