What is the principal protein component of hair, skin, and nails?

The principal protein component of hair, skin, and nails is keratin. This fibrous protein is crucial for providing structural support and strength to these tissues. Keratin is characterized by its resilience and resistance to degradation, which makes it an essential element for maintaining the protective barrier functions of the skin and for the durability of hair and nails.

Collagen, while important for skin elasticity and strength, primarily serves as a structural protein in connective tissues rather than being a direct component of hair or nails. Elastin, on the other hand, provides elasticity to skin and other tissues but does not play a role in the formation of hair and nails. Fibrin is involved in the clotting process of blood and is not related to the composition of hair, skin, or nails. The focus on keratin highlights its critical role in the health and integrity of these structures in the body.