Hair is composed chiefly of a protein called keratin which is present in all horny growths such as the fingernails. The chemical composition of hair is carbon (50.65%), hydrogen (6.36%), nitrogen (17.14), sulphur (5.0%) and oxygen (20.85%).
The chemical composition of hair varies according to the color of the hair. Dark hair has the most carbon with less amounts of oxygen and sulphur. Light hair contains less carbon and hydrogen but more oxygen and sulphur.