What is hair made up of and what is its structure?

Hair is made up of a strong protein called ‘keratin’, which is contains 21 different amino acids. The hair shaft consists of the cuticle, the cortex and the medulla. The cuticle is the outer layer of the hair shaft, and is made up of multiple layers of translucent cells, which overlap each other like shingles on a roof.

When the layers are smooth and flat against each other, the hair reflects more light and looks shiny. The middle layer of an individual hair is called the cortex, which comprises three quarters of the hair shaft. The pigment or melanin, gives hair its color and it is located in the cortex. There are two types of melanin; eumelanin, which is the black pigment, and the pheomelanin which gives red or yellow pigment. The core of the hair shaft is called the medulla.