What is the role of a serum in hair care?

The role of a serum in hair care primarily revolves around its ability to coat the hair and provide shine. Serums are often formulated with lightweight oils and silicones that create a protective layer over the hair shaft. This coating helps smooth the hair cuticle, reducing frizz and enhancing the overall appearance of the hair by adding a glossy finish. The protective barrier formed by the serum can also help seal in moisture, which is beneficial for maintaining healthy hair.

The other options, while related to hair and scalp care, do not accurately describe the specific function of a serum. For example, adjusting hair color pertains to hair dyes or color treatments, while clarifying the scalp and exfoliating the scalp involve cleansing and treatment products designed to remove buildup or dead skin, rather than providing shine or protective coating.