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. Their growth is affected by several different factors, including age and health. Children’s nails grow quickly until puberty, when growth slows to 50 percent of its previous rate. Pregnant women also experience accelerated nail growth – hormones boost metabolism and increases circulation, which causes nails to grow more quickly.
