The root of the hair is a place where body cells band together to form a protein that creates hair. It is just beneath the skin and located in a small tube called the hair follicle. This part of the body dictates how straight or curly the hair is once it is formed. Beneath this follicle are blood vessels that feed the root to allow the hair to grow. Maintaining a healthy diet contributes to the strength, shininess, and growth rate of the hair.
Hair follicles are attached to sebaceous glands that produce sebum, which determines how thick a person’s hair will be. The overall straightness or curliness of a person’s hair is also determined in the same area. In addition, follicles grow hair in cycles, so when a person shaves, he or she may notice that the hair grows back unevenly. Contrary to some myths, shaving or waxing does not irritate the root of the hair into producing thicker or darker hair. Sun exposure breaks down the melanin in hair, so it may seem like hair removal makes hair darker, but the darker shade is actually the original hair color.
The hair root is essentially alive and pushes hair out of the follicle as it grows. Once hair can be seen above the skin, it is just dead skin cells. If the hair was still alive above the skin, a person would likely be able to feel water on the hair and haircuts might be painful. Some types of hair removal pull the root of the hair out instead of just cutting hair at its base above the skin. These procedures are usually painful, and it can take the body weeks to rebuild the root and push more hair above the skin.
Just like the rest of the body, the root of the hair needs nutrients to maintain normal growth. When a person’s diet is not optimal, the body diverts nutrients to more important functions and growth. This can lead to dull, brittle hair that does not grow as fast as it could. Sometimes a poor diet also encourages the hair follicles to go into resting mode, and new hairs do not form when hair naturally falls out, leading to bald spots. On a healthy diet, a person can expect his or her hair to grow about ½ inch (1.27 cm) per month, with old hair falling out every two to six years.