Which statement best describes the action of conditioners on hair?

Conditioners are designed to coat the hair shaft, which serves multiple purposes, including providing a temporary protective layer and delivering moisture to the hair. This coating action helps to smooth the cuticle, reduce frizz, and improve the overall appearance and manageability of the hair. When conditioners are applied, they penetrate or adhere to the hair, infusing it with moisture and essential nutrients, which can enhance shine and softness. The effectiveness of conditioners lies in their ability to create a barrier that retains moisture and protects hair from environmental stressors.

In contrast, the other options present misunderstandings about how conditioners function. For instance, conditioning agents do not strip the hair of moisture; rather, their goal is to hydrate and protect. Additionally, while conditioners can help manage build-up over time, they do not eliminate all types of build-up immediately. Lastly, conditioners are effective on both damp and dry hair, but their primary benefit is often realized when applied to wet hair after cleansing, as this allows the product to distribute and penetrate more effectively.