Your Hair

The Basics

What Is Hair?

Hairs are thin strands of hardened protein packed into layers. The hard outer layer you see is called the cuticle (say: KYOO-tih-kul). It protects the two softer inside layers, the cortex (say: KOR-teks) and the medulla (say: meh-DUL-uh).

Which Body Parts Have Hair — and Which Don’t?

When you think of your hair, you probably think of the hair on your head. But there's hair on almost every part of your body. (Places that don't have hair include the lips, the palms of the hands, and the soles of the feet.)

Some of the hair on your body is easy to see, like your eyebrows and the hair on your head, arms, and legs. But other hair, like that on your cheek, is almost invisible.

Why Do People Have Hair?

Depending on where it is, hair has different jobs. The hair on your head keeps your head warm and provides a little cushioning for your skull. Eyelashes protect your eyes by decreasing the amount of light and dust that go into them, and eyebrows protect your eyes from sweat dripping down from your forehead. Hairs inside the nose filter out dust, pollen, and other irritating particles.

How Does Hair Grow?

Whether hair is growing out of your head, arm, or ankle, it all rises out of the skin in the same way. It starts at the hair root, a place beneath the skin where cells band together to form keratin (the protein that hair is made of). The root is inside a follicle (say: FOL-ih-kul), which is like a small tube in the skin.

As the hair begins to grow, it pushes up from the root and out of the follicle, through the skin where it can be seen. Tiny blood vessels at the base of every follicle feed the hair root to keep it growing. But once the hair is at the skin's surface, the cells within the strand of hair aren't alive anymore. The hair you see on every part of your body contains dead cells. That's why it doesn't cause pain when someone cuts your hair with scissors!

Nearly every hair follicle is attached to a sebaceous (say: sih-BAY-shus) gland, which is sometimes called an oil gland. These sebaceous glands produce oil, which makes the hair shiny and a bit waterproof. Sometimes, like during puberty, these glands can pump out too much oil and a person's hair may look greasy. Time for a shampoo!

Hair Today, Gone Tomorrow!

You have more than 100,000 hairs on your head, but you lose some every day. About 50 to 100 hairs fall out each day while you're washing your hair, brushing or combing it, or just sitting still. But don't worry, new hairs are constantly replacing those that have fallen out.

Each hair on your head grows for about two to six years. Then it rests for a few months and finally falls out. It is replaced by a new hair, which begins to grow from the same hair follicle. This cycle of hair growing, resting, falling out, and being replaced helps to maintain just the right number of hairs on your head.

Where Does Hair Color Come From?

What type of hair do you have — black and curly, blond and straight, or some other combination? Hair color comes from melanin (say: MEL-uh-nun), the substance that gives hair and skin its pigment. The lighter someone's hair, the less melanin there is. A person with brown or black hair has much more melanin than someone with blond or red hair. Older people lose the melanin pigment in their hair as they age, making their hair look gray or white.

Often, a person's skin color goes with the color of their hair. For example, many blondes have light skin, whereas many people with darker skin have dark brown or black hair. And don't forget genes (genes are what you inherit from your parents): Usually, a kid's hair color is determined by one or both parents' hair color.

When it comes to hair texture, your hair follicles make a difference. Some hair follicles are structured in a way that produces curly hair, whereas others send out straight hair. Follicles also determine if your hair will be thick and coarse or thin and fine.

How to Take Care of Your Hair

Wash It

With hair, the main thing is keeping it clean. Some people wash their hair every day, but others do it just once or twice a week. It depends on your hair and what kind of things you've been doing, like exercising or swimming.

When you wash your hair, use a gentle shampoo and warm water. Lather up using your fingertips, rather than your fingernails. You might use a conditioner or a shampoo containing a conditioner. This can take the tangles out of your hair and make it look smooth. But depending on your hair, it can also make it look flat and oily. Rinse your hair with plenty of clean water. Dry it gently with a towel and use a wide-tooth comb to untangle it.

Be Gentle

Be kind to your hair — wet or dry — by being gentle when you comb or brush your hair. Don't yank on knots too hard and don't wear your ponytails and braids too tight. This can irritate your scalp. And if you use curling irons or blow-dryers, be careful and ask for adult help when needed. You don't want to burn yourself.

Eat Healthy

Here's an easy way to have great-looking hair: Eat a healthy diet. It's not as weird as it sounds. A nutritious diet helps your body from the inside out!