Which section of the hair is primarily affected by heat styling?

Heat styling primarily affects the cuticle, which is the outermost layer of the hair. The cuticle is made up of thin, protective scales that overlap like shingles on a roof. When heat is applied through tools like curling irons, flat irons, or blow dryers, it can cause these cuticle scales to become damaged or lifted. This damage manifests as dryness, frizz, and a reduction in shine.

The cuticle serves as the first line of defense for the inner layers of the hair, and if it is compromised, the beneath layers can also suffer. This is particularly important for hairstylists to understand, as maintaining the integrity of the cuticle is essential for the overall health and appearance of the hair. Strategies such as using heat protectants can help to shield the cuticle from high heat and preserve the hair's structure.