Oklahoma Cosmetology Board Practice Exam 2026 - Free Cosmetology Practice Questions and Study Guide

The function of a hair moisturizer is primarily to add hydration and prevent dryness. Hair can often become dry due to various factors, including environmental conditions, heat styling, and chemical treatments. Moisturizers work by penetrating the hair shaft and providing essential moisture, which helps maintain the hair's elasticity, softness, and overall health. By keeping the hair hydrated, moisturizers can also reduce the likelihood of breakage and frizz, leading to a smoother and more manageable appearance.

Other functions described in the other choices do not align with the primary purpose of a hair moisturizer. While volume, styling, and color longevity are important aspects of hair care, they typically involve different types of products specifically created for those purposes, such as volumizers, styling gels, or color-preserving shampoos and conditioners. Therefore, the correct choice highlights the essential role of hydration in maintaining healthy hair.