Which layer of the hair contains color pigment?

The cortex is the layer of the hair that contains the color pigment, which is responsible for the natural and artificial colors seen in hair. This layer is made up of long, coiled protein chains called keratin, and it has a dense structure that provides strength and elasticity to the hair shaft. Melanin, the pigment that gives hair its color, is found within the cortex, and the amount and type of melanin present is what determines the hair color of an individual.

In contrast, the cuticle is the outermost layer of hair that serves primarily as a protective barrier. While it does not contain pigment, it plays a crucial role in protecting the underlying layers. The medulla, which is the innermost layer, may be present in some people and is often non-functional in fine hair types, but it typically does not contain color pigment either. The term "outer layer" can refer to the cuticle, which likewise does not hold any pigment, emphasizing that the primary role of the cortex is to house the color associated with hair.