Hair is a complex structure with multiple layers, each contributing to its overall health and appearance. This article explores the hair cortex, a central component that significantly influences hair’s characteristics and well-being.
Defining the Hair Cortex
The hair cortex is the middle and thickest layer of the hair shaft, situated between the outermost protective layer, the cuticle, and the innermost core, the medulla. This layer makes up the bulk of the hair’s mass, accounting for approximately 80% of its strength and elasticity. The primary components of the cortex are keratin fibers and melanin granules.
Keratin, a fibrous protein, forms long, spiral chains within the cortex. These chains are organized into larger bundles, giving the hair its robust structure. The keratin proteins are held together by various bonds, including disulfide bonds and hydrogen bonds, which contribute to the hair’s shape and flexibility. Melanin, the natural pigment, is also stored within the cortex, embedded between these keratin fibers.
The Cortex’s Important Roles
The cortex’s tightly packed keratin fibers provide hair with its strength and elasticity. This structural arrangement allows hair to withstand daily stresses and return to its original shape without breaking easily. The cortex’s integrity influences the overall health and resilience of hair, allowing it to stretch and then recover its form.
The cortex is also the layer where melanin, the natural pigment, is stored. The amount and type of melanin determine the hair’s color, ranging from black to brown, blonde, and red. Eumelanin provides black and brown tones, while pheomelanin is responsible for yellow and red shades. The distribution and concentration of these pigments within the cortex create the wide spectrum of natural hair colors.
Protecting Your Hair Cortex
Maintaining the hair cortex is important for healthy hair, as it is responsible for strength, elasticity, and color. When the cortex is compromised, hair can become rough, dry, and lacklustre. Common factors that can damage the cortex include excessive heat styling, which can harm keratin proteins and disulfide bonds, and chemical treatments like coloring or perming, which can break down the hair’s internal structure.
Exposure to UV radiation and harsh brushing can also weaken the cortex. To maintain the cortex’s health, use heat protectants before styling. Minimizing chemical processing and choosing lower heat settings when styling can also reduce damage. Gentle handling, such as avoiding aggressive brushing, and using proper conditioning treatments can help support the cortex’s structure and retain moisture.