What is the primary component of hair?

The primary component of hair is keratin, a fibrous structural protein that is a key building block of not only hair but also nails and the outer layer of skin. Keratin provides strength, flexibility, and resilience, making hair durable and able to withstand various environmental factors. This protein is produced by keratinocytes, the cells located in the hair follicles, and it comes in different forms. The specific arrangement and type of keratin contribute to the characteristics of different hair types, such as curliness or straightness.

Other components such as collagen, elastic fibers, and fatty acids serve important roles in the skin and other tissues, but they do not form the main structure of hair. Collagen is primarily found in connective tissues, providing support and structure; elastic fibers contribute to the elasticity of skin and other tissues; and fatty acids are associated with the sebaceous glands and skin's barrier function rather than the structure of hair itself. Thus, keratin is uniquely suited to fulfill the role of providing the structural integrity of hair.