What is the main effect of heat on hair during styling?

Heat plays a significant role in altering the shape and texture of hair during styling. When heat is applied to the hair, it affects the hydrogen bonds within the hair's structure. These bonds are responsible for the hair's shape and texture at a molecular level.

For instance, when styling tools such as curling irons or flat irons are used, the heat temporarily breaks down the hydrogen bonds, allowing the hair to be reshaped. As the hair cools, these hydrogen bonds reform in the new shape, which is why stylists can create curls, waves, or straighten hair effectively. This property allows for versatile styling options, demonstrating the impact of heat on the physical characteristics of hair.

Moisturizing the hair pertains more to product application rather than the direct effects of heat. While heat can influence the moisture content temporarily, it does not serve the primary function of moisturizing. Changing hair color involves chemical processes rather than heat styling, and increasing weight isn't a typical effect of applying heat; in fact, heat might sometimes lead to dehydration, potentially making hair lighter rather than heavier. Thus, the alteration of shape and texture remains the primary effect of heat during styling.