The Hair has three different layers:
1. Cuticle, or the outer layer
2. Cortex, or the inner structure
3. Medulla, an area that is not developed in all hair
The Cuticle is composed of 5 – 10 overlapping layers. When healthy it’s smooth, and lays flat. The hair appears healthy and shiny, and works to protect the inside. When the cuticle is damaged, the outer layers are raised, exposing the inside of the hair and leading to damage and a dull appearance.
A healthy cuticle supports an even uptake of chemical products. A damaged, open cuticle allows chemical products to be absorbed more quickly and thus more unevenly. That can mean unwanted and dark results with color.
The Cortex, the inner middle layer, is the most important and complex part of the hair.
Because it contains protein chains, hydrogen bonds, salt bonds and disulfide bonds, it is relevant for chemical services like coloring, perming, straightening or keratin treatments. Because of its inner structure, the Cortex is responsible for strength and flexibility. It also contains the pigments (melanin) that determine natural hair color.
A cortex cell contains Macrofibrils.
Each Macrofibril consists of Microfibrils.
Microfibril (Intermediar Filaments) consists of Protofibrils, each made of Protofilaments.
Each Protofilament is made of Alpha-Helices.
In the innermost the hair is made of disulfide, ionic and hydrogen bonds, that forms the Alpha-Helix.
The Medulla is the innermost layer of the hair. Because it’s not present in all hair, mainly normal to coarse hair textures, it also has nothing to do with how the hair responds to chemical processing. However, it can enhance the shine and color of hair by encouraging light reflection.
Between each cortex cell, between each cuticle cell and between the cortex and the cuticles there is a cell membrane complex. This complex consists of lipids and proteins that act like glue, holding hair components together. The matrix surrounds the helical filaments.
Lipid is a collective term for the various groups of fatty acids, triacyglyceride (fat and fat oils) waxes, phospholipids, sphingolipids, lipopolysaccharides and isoprenoids (steroids, carotinoids, etc).
Lipids are a natural part of hair. A balanced lipid level guarantees strong, shiny hair full of elasticity. Chemical and mechanical processes can lead to a loss in lipids making hair feel weak and porous and making it look lifeless and dull.
Learn more about our IntraLipid™ Technology here.