Body Hair

Body hair is something that almost everyone has, but most people don’t think much about it. You have millions of hair follicles on your body. That’s a lot of hair — even if most of it is too fine to notice. From the tiny hairs on your arms to the thicker ones on your head, body hair plays an important role in protecting and supporting your health.

Throughout your life, the amount and type of hair you have can change with age, hormones and health. Changes like thinning hair or unexpected hair growth are common. But if they worry you or affect how you feel about yourself, a healthcare provider can help.

Types of body hair

The three types of body hair are:

• Lanugo hair: When hair follicles form during fetal development, soft, fine lanugo hair grows on the fetus. This hair sheds by 36 to 40 weeks’ gestation.
• Vellus hair: After lanugo hair sheds, vellus hair replaces it. Vellus hair is thin and short. It covers most of your body.
• Terminal hair: Terminal hair is thicker, longer and coarser. It includes hair on your scalp, eyebrows and eyelashes. During puberty, this type of body hair starts growing on your armpits and pubic region. You may also see terminal hair on your face, chest and belly.

Is it healthy to have body hair?

Yes, body hair is healthy. It has many important functions, including:

• Protection: Hair provides a physical barrier that blocks UV rays from reaching your skin. Your eyebrows and eyelashes protect your eyes from dust, dirt and sweat. Your nose hair and ear hair help keep germs and foreign objects out.
• Thermoregulation: Hair helps manage your body temperature by providing an insulating layer. When you’re in a cold environment, your body hair stands up. This keeps warm air in, close to your body.
• Wound healing and skin repair: Stem cells in your hair follicles can travel to the epidermis (top) layer of your skin to help with tissue repair. The hair follicles also release special proteins called cytokines to promote skin growth.
• Sensory aid: Hair follicles are sensitive to even the lightest touch because they’re surrounded by nerve endings. These nerves help you feel hair movement.
• Identity: For some people, healthy hair plays an important role in how they view themselves. In a way, for some, it can project who you are to the world.

Where is body hair located?

You have body hair almost everywhere on your skin. Most of this hair is vellus hair. The only places where hair doesn’t grow are:

• Your lips
• The palms of your hands
• The soles of your feet

What are the parts of body hair?

Each of the hairs on your body is made up of various parts. Starting at the top, the parts of your hair include:

• Hair shaft: This is the part of your hair that sticks out of your skin that you can see.
• Hair root: This goes down through your skin to the dermis layer (the layer between the epidermis and hypodermis layers).
• Hair follicle: This consists of a sheath of skin and connective tissue. It surrounds the hair root.
• Arrector pili: Each hair follicle is attached to a tiny muscle called the arrector pili. This muscle makes your hair stand up.
• Hair bulb: At the base of each hair, the hair root widens and forms a round hair bulb. New hair cells are constantly being made in the hair bulb.
• Hair papilla: Found inside the bottom of the hair bulb, the hair papilla supplies the hair root with blood.

What determines the color of your hair?

The amount of melanin you have in hardened cells in your hair follicles determines your hair color. Melanin is a pigment that’s also responsible for your eye and skin color. Hair colors come from two types of melanin:

• Eumelanin creates black or brown hair. (Diluted eumelanin creates blond hair.)
• Pheomelanin creates auburn or red hair.

How does body hair change with age?

As you get older, you start to lose the melanin in your hair. When you have less melanin, air gets trapped inside your hair. When this occurs, your hair begins to lose its color and it eventually turns white or gray.

Your rate of hair growth and hair density also decrease with age.

How many hairs are on a human body?

The amount of hair on your body depends on various factors, including your genes, age, sex and ethnicity. The average human body has about 5 million hair follicles. More than 100,000 of those hairs are on your head. Hair color also makes a difference in the number of hairs you have. Brunettes have about 110,000 hairs on their head, while blondes have closer to 150,000.

How does hair grow?

New hair cells multiply at the base of your hair follicle, which forms a new hair. Then, the hair grows in three cycles:

• Growth phase (anagen phase): During the growth phase, your hair will continue to grow as long as new hair cells grow in the hair bulb. At any given time, about 90% of your hair is in the growth phase.
• Transitional phase (catagen phase): Near the end of the anagen phase, the hair root begins to separate from the hair papilla. The transitional phase lasts two to four weeks.
• Resting phase (telogen phase): The blood supply is cut off once the hair root completely separates from the hair papilla. The hair gradually pushes out of your skin and falls out. The resting phase lasts several months.

How long can hair grow?

The length that hair can grow depends on its growth phase. The growth phase of body hair lasts varying amounts of time, depending on its location on your body.

The hair on your head can grow to over 1 meter (3.2 feet) because its growth phase can last several years. Facial hair (especially your eyelashes and eyebrows), nose hair and ear hair grow at a slower pace. Their growth phase is 100 to 150 days, so they don’t get that long.

What causes excessive body hair growth?

Excess body hair is usually the result of hirsutism or hypertrichosis.

Hirsutism

Hirsutism affects women. It occurs when thick, dark body hair grows excessively in areas that are more typically seen in men. This may include your face (upper lip, chin or sideburns), trunk (chest, nipples, belly or back) or limbs (armpits, shoulders or inner thighs). High levels of male hormones usually cause hirsutism.

Hypertrichosis

Hypertrichosis can affect men and women. It occurs when hair grows excessively anywhere on your body. This hair may be light and fine or dark and thick. High levels of male hormones aren’t the cause of this condition. Certain medications or serious health conditions typically lead to hypertrichosis.

What causes excessive hair loss?

Adults lose 70 to 100 hairs on their head every day during the resting phase. But you don’t notice it because new hairs are already growing and replacing them.

But hair loss may become more noticeable if you have:

• Anagen effluvium: Your hair roots are damaged during the growth phase.
• Telogen effluvium: A lot of hairs go into the resting phase at the same time

When no new hair grows and replaces the hair that falls out, that part of your skin becomes bald. This is called alopecia. Sometimes, your hair may grow back. But other times, it can be permanent. There are many causes of hair loss. Some of the most common include:

• Alopecia areata
• Male pattern baldness
• Female pattern baldness
• Lupus and other hormonal disorders
• Certain medications, like chemotherapy
• Fungal infections, like ringworm

What are the methods for removing body hair?

To prevent body hair growth, there are several different ways to remove it. Some methods are permanent. Hair removal methods include:

• Shaving: Shaving is the most common way to remove body hair. You use a razor to cut the hairs at the surface of your skin. Shaving is usually painless. But the results don’t last long. You may need to shave every day or every few days.
• Waxing: You apply hot or cold wax to the surface of your skin. Then, you quickly remove the wax, which pulls out the hairs. Waxing can be painful. But the results last a few weeks or more.
• Depilatories: You apply a lotion, cream or gel to your skin. Then, you wait for a certain amount of time and rinse it off. The depilatory dissolves the unwanted hair. Results typically last longer than shaving.
• Threading: Threading is an option for removing small areas of hair, like around your eyebrows. You go to a salon or spa, where an experienced threading specialist rolls two twisted cotton threads over unwanted hairs, which rip them out. Results last up to five weeks.
• Laser hair removal: A board-certified dermatologist uses a laser to emit a beam of light, which your hair pigment absorbs. After about six treatments, the process destroys the hair follicle, and the hair won’t grow back. At-home laser hair removal devices take longer to produce results.
• Electrolysis: A board-certified dermatologist sends an electrical current through the hair follicle. This damages the follicle and prevents hair from growing. It can take several treatments to see permanent results.