What is the primary function of the cuticle layer of the hair?

The primary function of the cuticle layer of the hair is to protect the inner layers of the hair. The cuticle is the outermost layer of the hair shaft and consists of overlapping, scale-like cells. This structure helps to shield the more delicate layers underneath, such as the cortex and medulla, from environmental damage, mechanical wear, and chemical exposure. By providing this protective barrier, the cuticle plays a crucial role in maintaining the overall integrity and health of the hair, preventing issues such as split ends and breakage.

While the cuticle can contribute to the perception of shine and luster by reflecting light, this is not its primary function. Additionally, hair growth occurs from the hair follicle located beneath the scalp, and the cuticle does not actively contribute to this process. Hair color is determined by the pigmentation in the hair's cortex and is not added by the cuticle layer. Thus, the protective role of the cuticle is essential for maintaining the hair's durability and resilience in the face of various challenges.