Which type of product is primarily used for styling hair?

The primary purpose of gel or mousse is to style hair, making them essential products in the cosmetologist's toolkit. These products are designed to help manipulate the hair's texture, control its shape, and provide hold and volume. Gels often create a firmer hold, making them ideal for defined styles, while mousses provide a lighter hold and can enhance volume and body in the hair.

Moisturizers, shampoos, and conditioners play different roles in hair care. Moisturizers are typically used to hydrate the hair and improve its health rather than for styling. Shampoos are primarily intended for cleansing the hair and scalp, removing dirt, oil, and product buildup. Conditioners are used after shampooing to nourish and detangle the hair, improving its manageability and shine, but they do not provide styling capabilities like gel or mousse does. Therefore, when it comes to the primary function of styling hair, gel or mousse is the clear choice.