Fingernails are made of multiple layers of a strong material called keratin. Keratin is a protective protein produced by the body. It consists of proteins that form filaments and enzymes.
Nails grow when new cells form at the base of the nails under the cuticle, in an area known as the matrix. The new cells force the older cells to move away from the matrix where they hardened and become more compacted.
Fingernails grow approximately 0.39 inch every 100 days depending on gender, age and season of the year. Nails tend to grow faster during the summer. Males and young people have faster nail growth than females and older people. Fingernails grow faster in the less used hand.