What is hair ?
Though it is different from the skin in many ways, hair, like the horny epidermis, is derived from cells.Nutrition is carried through capillary vessel to the hair bulb. A small mass of cells at the base of the hair follicles,
called the “Matrix”, produces hair.Hair grows and pushes up to the surface of the scalp. Hair grows about 0.2 to 0.4 mm per day and the sebaceous
The formation of hair
Hair is formed of a combination of protein called Keratin and Water.
Karatin is harder and stronger than the protein of the internal organs of the human body. Keratin yields several kinds of amino-acid by hydrolysis.The amino-acids composing Keratin are as follows;Glutamic acid, Threonine, Valine, Cystine, Methionine, Alanine, Isoleucine, Tryptophan, Phenylalanine, Arginine, Proline, Lysine, Serine, Glycine, Histidine, Aspartic acid, Tyrosine and Hydroxylysine.
The character of Hair
・Hair diameterMax: 0.2mm (Mustache)General:0.05-0.15mm (Hair on scalp)Min: 0.005mm (Downy hair)
・Hair growing speed 0.2-0.4mm/day (Eyebrow 0.18mm/day) 6-12mm/month, 7-14cm/year
・Water content Average: 10-13% (Healthy hair) Max: 30% (Water absorption)
・Maximum hair growth in generalJapanese: 70-80cm, Americans and Europeans: 70cm, Native Americans: 90cm,
Chinese: 90-100cm,Africans: 25-40cm
・Tensile strength of healthy hairAbout 120-180g/hair
・Quantity of hair on head (for Japanese)Approximately 100,000 hairs
・Physiological (natural) hair loss50 to 100 hairs per day
・Elasticity of normal hair Max: 1.4-1.5 times
・Deterioration Non deterioration up to about 120℃ (about 250 degrees Fahrenheit)Expands with heat at more than about 120℃, turns from black to brown and becomes weak.
・Chemical Reaction Weaker against alkalis. Relatively stronger against acids.