Which part of the hair contains the pigment that determines hair color?

The cortex is the part of the hair that contains the pigment, specifically melanin, which determines hair color. This middle layer of the hair shaft is crucial as it provides strength, color, and texture. The amount and type of melanin present in the cortex are what cause variations in hair color, from blond to brunette to black.

The cuticle, while important for protecting the hair and contributing to its shine, does not contain any pigment. The medulla, which is the innermost layer, is often absent in fine or light-colored hair and is not responsible for coloration. The hair shaft is the overall structure that includes the cuticle, cortex, and medulla, but it is the cortex that specifically houses the pigment determining hair color.