What are fingernails made of?

In order to understand both how to keep your nails healthy and how they can act as an indicator of health problems, first you have to know that fingernails are made of layers of a protein called keratin. This protein is also found in your skin and hair [source: Mayo Clinic].

But your nails are more than just keratin. Your nails comprise several different components:

The nail plate is the part of the nail that you can see.
The skin around your nails is referred to as nail folds.
The skin that is covered by your nail is known as a nail bed.
A cuticle is the tissue that covers the bottom of your nail to protect newly formed keratin as your nail grows.
The white half-moon seen at the base of your nail is called a lunula.

[source: Mayo Clinic]

Changes and discoloration to any parts of your fingernails can indicate that something is wrong with your nail health, or even your overall body health. For example, slow or halted nail growth could indicate a health concern that involves more than just your fingertips.

On average, fingernails grow at a rate of about 0.08 to 0.12 inches (2 to 3 millimeters) a month. Therefore, it takes about four to six months for a fingernail to fully regenerate. Interestingly, the nails of the hand you use most often grow slightly faster than the nails of your non-dominant hand [source: American Academy of Dermatology].

Now that you know the general structure of your nails, read on to learn about some of the problems that can develop there.