Even though all of us may have hair that looks different, we have one thing in common, that is the structure of our hair. Each strand consists of three layers: cuticle, cortex and medulla.

The cuticle is the top layer of hair. Like the skin, it is made up of a protein called keratin. It is transparent but very strong. It is layered fish-like scales and helps the cuticle protect the next layer. These scales can have as many as 7 overlapping strata, or as few as 3, bound together with a putty like substance. The cuticle reflects light, giving the hair its luster. If the cuticle is damaged, hair is dull and lacks luster.

The cortex is the thickest part of the hair strands and makes up more than 75% of the hair, providing strength and elasticity. In addition to determining the hair's texture, it's contains pigment granules that determine the color of our hair. Coarse hair contains more cortex and less cuticle than fine hair. The medulla is at the center of the hair. However very little is known about the biological function of this layer.