Which layer of the hair is responsible for its strength and elasticity?

The cortex is the layer of the hair that is primarily responsible for its strength and elasticity. This middle layer contains tightly packed fiber proteins known as keratin, which provide the hair with structure and durability. The cortex also influences the hair's flexibility, allowing it to bend and stretch without breaking.

In addition to its physical properties, the cortex contains melanin, which gives hair its color. Because the cortex forms the bulk of the hair shaft, it plays a crucial role in determining the overall health and appearance of the hair. Understanding the role of the cortex is essential for hair care practices, as damage to this layer can lead to weakened hair and a loss of elasticity, making it more prone to breakage.

It’s important to note that while the cuticle acts as a protective layer for the hair and can affect shine and overall appearance, it does not contribute to strength or elasticity. The medulla, found in the center of the hair shaft, is often not present in all hair types and has less impact on the hair's physical properties. The dermis is a layer of skin beneath the hair follicles and is unrelated to the hair structure itself.