* Keratin is a fibrous protein that is also found in the skin, but the structure of keratin in nails and hair is slightly different, giving them their unique properties.
* Nails are made up of hard, flat plates of keratin that grow from the nail matrix at the base of the finger or toe.
* Hair is made up of strands of keratin that grow from follicles in the skin. The shape of the hair follicle determines the shape of the hair strand (straight, curly, etc.).
While both nails and hair are mostly keratin, they do contain small amounts of other substances:
* Nails: Contain trace amounts of water, lipids, and minerals.
* Hair: Contains trace amounts of water, pigments (melanin), and trace elements like zinc and iron.
It's important to note that the structure of the keratin in nails and hair is what makes them strong and resilient, but it also makes them resistant to breaking down. This is why it takes a long time for nails and hair to grow back after they've been cut or broken.