What is the importance of amino acids for hair?
The individual nature of our hair is genetically determined. Depending on the structure and hair color, we have up to 150,000 hairs on our head. Of these, approximately 30 to 100 hairs typically fall out each day, which grow back after a resting phase.
Structure of the hair fiber
Broadly speaking, each hair fiber consists of three layers:
Cuticle (Latin: little skin): The outer scale layer consists of keratinized cells that overlap in up to 10 layers like roof tiles, preventing the hair from drying out. A smooth surface of the scales reflects light and ensures shiny hair.
Cortex (Latin: bark): The fiber layer underneath makes up the main part of the hair. The cortex consists of keratin, a chain of amino acids or proteins twisted together like a rope. The fiber layer keeps the hair elastic, supple, and tear-resistant. Chemical treatments such as dyeing, bleaching, or perms, as well as environmental influences like excessive UV radiation, damage the healthy keratin structure and cause a porous surface of the hair fiber.
Medulla (Latin: marrow): The marrow canal inside the fiber layer contains, among other things, metabolic products produced during the formation of the fiber layer.
Each hair root also has its own sebaceous gland, which surrounds the hair fiber with a natural, smoothing layer of fatty acids.
Structure of keratin from amino acids
Human hair consists of keratin, which is also a component of our skin and nails. Keratin is formed in our body through the combination of 18 different amino acids or proteins. The keratin fibers that form the shaft of the hair are held together by various polypeptide bonds. The so-called cysteine bridge, built from the amino acid cysteine, gives the keratin fiber its greatest strength.
Keratin-damaging factors
External damaging factors can cause the breakdown of the keratin-cysteine bridge. Such damaging influences include: chemical hair dyes, perms, aggressive shampoos with harsh surfactants, synthetic hair sprays with PVP or other microplastic copolymers. Blow-dry heat, hair straightening, curling irons, or excessive UV radiation also damage the keratin fiber, making it porous and full of holes. The consequences: increased hair breakage, frizz—that is, statically charged, dull hair that is difficult to comb—as well as split ends.
