Chemical Composition of Hair

Hair is made up mostly of protein, which accounts for some 65 to 95% of its weight. These proteins contain the following amino acids in normal hair:

Amino Acid Amount

Lysine 2.8

Histidine 0.8

Arginine 5.6

Aspartic Acid 5.0

Threonine 6.9

Serine 11.7

Glutamic Acid 11.1

Proline 3.6

Glycine 6.5

Alanine 4.8

Cystine 17.5

Valine 5.9

Methionine 0.5

Isoleucine 2.7

Leucine 6.1

Tyrosine 1.9

Phenylalanine 1.4

It is also made up of the following elements: Ca, Mg, Sr, B, Al, Si, Na, K, Zn, Cu, Mn, Fe, Ag, Au, Hg, As, Pb, Sb, Ti, W, Mo, I, P, Se.

Lipids: sebum, free fatty acids, and neutral fats esters, glycerol, waxes, hydrocarbons, and alcohols.

Water: Hair has the capacity to absorb water, increasing its weight between 12 - 18%.