Hair - a mixed bag
A single hair contains a number of different substances, including carbon, oxygen, nitrogen, hydrogen and sulphur - and on average about 10 per cent water. The main constituent of any hair - some 90 % - is the so-called keratin, a highly structured protein also found in our upper layer of skin and in our nails.
Hair - constituents like beads on a string
As a molecule, keratin is made up of smaller units, amino acids, resembling beads on a string. The diameter of an individual hair varies from one person to the next, with the average somewhere between 0.05 and 0.09 mm. Keratin is a very durable substance, as witnessed by the virtually intact hairs found in Egyptian graves dating back centuries.