Minnesota Cosmetology State Practice Exam 2026 - Free Cosmetology Practice Questions and Study Guide

The correct answer highlights the fundamental difference in how these two types of hair color interact with the hair shaft. Permanent hair colors contain larger molecules that are designed to penetrate deeper into the hair cuticle and cortex, allowing them to create a long-lasting effect. This deep penetration is what enables permanent hair color to change the hair's natural pigment and achieve a lasting color change.

In contrast, semi-permanent hair colors typically use smaller molecules that do not penetrate as deeply into the hair structure. Instead, they tend to coat the surface of the hair, providing temporary color that gradually fades with washing. This distinction in how these products function and their intended durations of effect is essential for understanding their application and results in cosmetology treatments.