Famous Cortex Hair Ideas. Not all hair contains the medulla, the hair's innermost layer. Web the cortex is the central part of the hair shaft and it's mainly made from a mix of proteins (mainly keratins) and natural pigments that form the colour of your hair.
The health of your cortex depends largely on the integrity of the cuticle protecting it. It serves as protection to the cortex. It contains most of the hair's pigment, giving the hair its color.
