What impact does excessive heat have on hair structure?

Excessive heat has a detrimental impact on hair structure, primarily causing dryness, breakage, and split ends. When hair is exposed to high temperatures—such as during the use of heated styling tools like curling irons, straighteners, or blow dryers—the outer protective layer of the hair, known as the cuticle, can become damaged. This damage leads to moisture loss, making the hair feel dry and brittle.

As the hair loses its moisture and natural oils, it becomes more prone to breakage, as the strands lack the hydration needed to remain flexible and resilient. Additionally, the weakened cuticle can result in split ends, where the hair fibers separate at the tip, further worsening the overall appearance and health of the hair. This understanding underscores the need for proper heat protection and conditioning treatments to mitigate the adverse effects of heat styling on hair.