How Your Hair Is Made

Hair is a filamentous protein, primarily keratin, that grows from follicles in the dermis of the skin. It is one of the defining characteristics of mammals. It gives us warmth, protection and a means of expressing our individuality and creativity. It even makes it possible to identify our friends, coworkers and family members.

In its healthiest state, your hair is a beautiful thing, reflecting light, shiny, lustrous and full of life. But it can also be a dead giveaway of poor health. Unusual breakage, brittleness and dullness are just a few of the indicators that your body needs some extra care.

Each hair grows from a small, saclike hole in the skin called a hair follicle. The follicle is filled with special cells that reproduce to produce new hair cells. The hair follicle is attached to a tiny muscle (arrector pili) that can make the hair stand up when pulled. It’s also home to many nerves that sense movement. At the bottom of the hair follicle is a structure that supplies it with blood, called the hair papilla.

The outer layer of your hair is a tough coating of flattened cells called the cuticle. It’s similar to the tiles on a terra-cotta roof, and it protects the softer, more vulnerable inner structures of the hair. The cuticle protects the follicle and helps the hair withstand the wear and tear of everyday use, but it can be worn away by harsh treatment, like over-brushing or too much exposure to sun and water. The loss of the protective cuticle is what causes split ends.

Hair is made up of three main sections, each with a different texture and structure:

– the cuticle: The outermost layer, made of flattened cell layers that overlap like the tiles on a terra-cotta tile roof. This is highly keratinized, and insoluble in water, which is what helps hair to be waterproof and durable.

-the cortex: The middle part, made of thicker and often pigmented tissues. The color of your hair is determined by the color of these cells.

– and the medulla: A soft, spongy center in some hairs. Coarse hair typically has a medulla, but fine hair rarely does.

The medulla is rich in nutrients, such as B vitamins, iron, zinc and selenium. These nutrients are important for maintaining healthy hair. A diet high in these nutrients can help prevent dryness, which is a common cause of brittle and dull hair.