What percentage of strength to the hair does the cuticle layer contribute?

The cuticle layer of the hair plays a vital role in its overall strength and integrity. This outer layer consists of overlapping, protective scale-like cells that help to shield the inner layers of the hair shaft from damage. The cuticle is essential for maintaining moisture and health within the hair, as well as lending some degree of resilience against physical and environmental stressors.

While specific percentages can vary based on different sources, the commonly accepted view is that the cuticle contributes approximately 20% of the overall strength of the hair. This is significant because it highlights the importance of maintaining the health of the cuticle through proper hair care practices, as damage to this layer can lead to weakened hair structure and increased susceptibility to breakage.

The contribution of other layers, such as the cortex and medulla, accounts for the remaining strength of hair, underscoring that while the cuticle is vital, it is only part of the complex structure that gives hair its overall durability.