Nails themselves are made of keratin (say: KAIR-uh-tin). This is the same substance your body uses to create hair and the top layer of your skin. You had fingernails and toenails before you were even born. Where do they come from?
It may look like your fingernails and toenails start growing where your U-shaped cuticle (say: KYOO-tih-kul) begins. But there's more going on under the surface. Nails start in the nail root, hidden under the cuticle.
When cells at the root of the nail grow, the new nail cells push out the old nail cells. These old cells flatten and harden, thanks to keratin, a protein made by these cells. The newly formed nail then slides along the nail bed, the flat surface under your nails. The nail bed sits on top of tiny blood vessels that feed it and give your nails their pink color.
Your fingernails grow slowly — in fact, they grow about one tenth of an inch (2.5 millimeters) each month. At that rate it can take about 3 to 6 months to completely replace a nail.
