Which part of the hair is primarily responsible for moisture retention?

The cuticle is the outermost layer of the hair shaft and plays a critical role in moisture retention. It consists of overlapping, scale-like cells that protect the inner layers of the hair. When the cuticle is healthy and intact, it allows moisture to be retained within the hair, preventing it from becoming dry and brittle. This protective layer helps to seal in moisture and other essential nutrients, contributing to the overall health and appearance of the hair.

While the cortex is the middle layer that provides strength, color, and texture to the hair, it is the cuticle that primarily functions to keep moisture from escaping. The medulla, which is the innermost layer, is not involved in moisture retention and is less significant in terms of the structural function of hair. The scalp, while essential for nourishing hair follicles and supporting hair growth, does not directly influence moisture retention in the hair strands themselves.

Therefore, the cuticle’s role in safeguarding and maintaining moisture makes it the primary part responsible for this essential aspect of hair health.