What is hair made of?

Your hair is made up of two distinct structures: the follicle and the shaft. The follicle, a tubelike segment in the epidermis, sits under the surface of the skin and extends down into the dermis. The base of the follicle contains tiny blood vessels that nourish the cells. The living part is the bulb at the base, or root, while the shaft--the part of the hair that we see above the skin--is actually dead. Pretty crazy, huh? Now, that hair shaft is made up of a protein called keratin. The inner layer of the hair shaft and the middle layer make up the majority of the shaft.

Your hair is made up of two distinct structures: the follicle and the shaft. The follicle is a tunnel-like segment in the epidermis portion of your skin. It resides under the surface of the skin and extends down into the dermis. The base of the follicle contains tiny blood vessels that nourish the hair cells. That's right - while it may seem that your hair is as far removed from your internal organs as your clothes or jewelry, each strand of hair has its own blood supply. Because of that, hair is greatly influenced by health and diet.
The living part of the hair is the bulb at the base, while the shaft - the part of the hair that we see above the skin - is dead. The hair shaft is made up of a protein called keratin. The inner layer (the medulla) and the middle layer (the cortex) constitute the majority of the shaft. Like the nail's structure, the hair's cuticle, which looks like a tile roof under the microscope, serves as the outer, protective layer that covers the medulla and cortex.