What is the fibrous layer of the hair that contains melanin and gives hair its color?

The cortex is the fibrous layer of the hair that plays a crucial role in determining the hair's color due to the presence of melanin. Melanin is a pigment produced by cells called melanocytes within the cortex. The amount and type of melanin in the cortex directly influence whether hair appears blonde, brown, black, or red.

The cuticle is the outermost layer of the hair shaft and primarily serves a protective role, while the medulla, which is the innermost layer, is often absent in fine hair and does not play a significant role in color. The bulb is the base of the hair follicle where hair growth begins, but it does not contain melanin itself; instead, it houses the cells that generate the hair. Understanding the specific functions and characteristics of each hair layer is essential for anyone studying hair biology in the context of practices such as waxing and hair care.