Kansas Cosmetology Practice Exam 2025 - Free Cosmetology Practice Questions and Study Guide

Heat styling tools can damage hair primarily by breaking down the hair’s natural protein structure. Hair is made up of a protein called keratin, and when exposed to high temperatures from styling tools like curling irons, flat irons, or blow dryers, the heat can denature this protein. This process weakens the hair shaft, leading to various forms of damage such as brittleness, split ends, and overall loss of integrity.

When hair is excessively heated, the water content within the hair can evaporate, further exacerbating damage by reducing moisture levels. This loss of moisture along with the alteration of the protein structure makes hair prone to breakage and affects its overall appearance and health. Thus, using heat styling tools without proper protection or moderation can significantly compromise the hair’s structural integrity. Understanding this allows cosmetologists to emphasize the importance of protective measures, such as heat protectant products, and to advise on safe styling practices.