The dominant element in human hair is protein. It accounts for 91% of hair fiber makeup.
Collagen is the main structural protein found in hair. Hair follicles are essentially a sheath of collagen that holds and nurtures the hair from the root. At the very base of the follicle is the papilla. The papilla is what links the follicle to the rest of the body and is also made up of collagen. The hair bulb is situated directly above the papilla. The papilla is what provides the hair bulb with nutrients needed to create new hair cells.
As hair cells are pushed upwards, they go through a process called keratinization. Hair cells are filled with fibrous proteins and lose their nucleus as they mature (which is why we say hair is dead). As the dead hair cells stack up, new hair is pushed out of the follicle and our hair “grows.” The hair that exits the skin is essentially a strand of woven keratin proteins. Depending on individual genetic components, hair cell proteins can form in different ways, resulting in different textures of hair.