What is the purpose of using a thermal cap during a conditioning treatment?

Using a thermal cap during a conditioning treatment is primarily aimed at enhancing the effectiveness of the products applied to the hair. The heat generated by the cap opens up the cuticle of the hair shaft, allowing conditioners and treatments to penetrate more deeply. This deeper penetration is crucial for delivering essential nutrients, moisture, and proteins to the hair, which can significantly improve its condition, strength, and overall appearance.

In contrast, other options do not align with the primary function of the thermal cap. Keeping the hair dry is not relevant, as the purpose is to create a warm, moist environment conducive to absorption. The use of a thermal cap does not focus on adding heat without electricity; rather, it utilizes the warmth from the user's body or pre-heating. Preventing color fading is a concern that relates more to the formulation of the products being used rather than the method of application with a thermal cap. Thus, the correct answer underscores the importance of heat in facilitating product absorption during conditioning treatments.