Colorado Cosmetology Written Practice Exam

Deep-conditioning treatments penetrate which layer of the hair?

1. Cortex

2. Cuticle

3. Medulla

4. Subcuticle

The correct answer is: Cuticle

Deep-conditioning treatments are meant to penetrate the cuticle layer of hair which acts as a protective barrier for the inner layers of the hair. The cuticle is made up of overlapping scales that help to keep moisture and nutrients inside the hair. The cortex, medulla, and subcuticle layers do not play a role in the absorption of the conditioning treatments, making them incorrect choices. The cortex is the middle layer responsible for giving hair its strength and color. The medulla is the innermost layer and is typically only found in thicker hair. The subcuticle is not a commonly used term but could refer to the layer just beneath the cuticle, which is still part of the cuticle layer and not the correct answer.