What is the main component of hair?

The main component of hair is keratin, which is a type of protein. Keratin is a fibrous structural protein that not only makes up the majority of hair but also forms the structure of nails and the outer layer of skin. This protein provides strength, resilience, and durability to hair, allowing it to withstand various environmental stressors.

While the other options are related to hair in different contexts—melanin contributes to the color of hair, collagen is a structural protein found in connective tissues and contributes to skin health, and protein, of which keratin is a specific kind, is essential for overall hair structure—keratin specifically is the primary component responsible for the hair’s physical properties. Understanding this distinction highlights why keratin is identified as the main component of hair.