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 heads. Of these, around 30 to 100 hairs usually fall out every day, and they grow back after a break.
Structure of the hair fiber
Roughly speaking, each hair fiber consists of three layers:
- Cuticula (Latin: cuticle): The outer layer of dandruff consists of horny cells that overlap in up to 10 layers like roof tiles and prevent the hair from drying out. A smooth surface of the scales reflects the light and ensures shiny hair.
- Cortex (Latin: bark): The underlying layer of fibers makes up the main part of the hair. The cortex consists of keratin, a chain of amino acids or proteins that are twisted together like a rope. The fiber layer keeps the hair elastic, supple and tear-resistant. Chemical treatments such as colouring, bleaching or perming, but also environmental influences such as excessive UV radiation damage the healthy keratin structure and cause the hair fiber to become porous on the surface.
- Medulla (Latin: Mark) The medullary canal inside the fiber layer contains, among other things, metabolic products that are produced when the fiber layer is built up.
Each hair root also has its own sebaceous gland, which surrounds the hair fiber with a natural, smoothing fatty acid layer.
Structure of keratin from amino acids
Human hair is made of keratin, which is also part of our skin and nails. Keratin is formed in our body by combining 18 different amino acids or proteins. The keratin fibers that make up the hair shaft are held together by various polypeptide compounds. The so-called cysteine bridge, built up from the amino acid cysteine, gives the keratin fiber its greatest strength.
Keratin-damaging factors
External damaging factors can cause the keratin-cysteine bridge to break. These are: chemical hair dyes, aggressive shampoos with harsh surfactants, synthetic hairsprays with PVP or other microplastic co-polymers. Heat from a hair dryer, straightening hair, curling irons or excessive UV radiation also damage the cysteine bridge of the keratin fiber. The result: increased hair breakage, statically charged, dull and hardly combable hair - the dreaded frizz - as well as split ends.