​​How is Hair produced and How does it grow ?

Hair is made of a tough protein called Keratin. First, your hair grows from Follicles within the skin. The part of the hair inside the follicle (below the skin's surface) is known as the Hair Root, while the portion you see protruding from the head is the Hair Shaft. At the base of the hair root is the Hair Bulb where nutrients are received and new cells are formed.
Taking nutrients from the Dermal papilla, the hair bulb generates new hair cells. As these cells move up through the hair root, they mature through a process called Keratinization, fill with fibrous protein and lose their Nucleus. When the cell loses its nucleus it is no longer alive. By the time the hair emerges from the skin it is merely fiber made of keratinized proteins.
In fact, your hair is approximately 91 percent protein, and is made up of long chains of amino acids. These chains are found within the fibers of the cortex of the hair. The amino acids of these chains are made up of the elements carbon, oxygen, hydrogen, nitrogen, and sulfur (are also the building blocks of the skin and nails) and are joined together by peptide bonds. Long chains of these peptide bonds are called polypeptide chains.