What is the outermost layer of hair called?

The outermost layer of hair is known as the cuticle. This layer serves as a protective shield for the inner structures of the hair, namely the cortex and medulla. Composed of overlapping flat cells, the cuticle helps to reduce moisture loss and protect the hair from environmental damage, such as UV rays and pollutants. Its condition and health can significantly impact the overall appearance of the hair, including shine and smoothness.

In contrast, the cortex is the middle layer and is responsible for the strength and color of the hair, while the medulla is an innermost layer that may not be present in all hair types. The follicle, on the other hand, refers to the skin structure that grows the hair but is not a hair layer itself. Understanding the distinct roles of these components is essential for effective hair care and styling.