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Why the Hair on the Head Grows Longer Than Body Hair

Perhaps, many of you have wondered why the hair on your head can grow very long, and the eyebrows or hair on your arms stop growing quite quickly. There is a rather simple but interesting explanation for this.

With 5-Minute Crafts, you’ll learn how our hair grows and why body hair is shorter than the hair on the head.

What is hair?

People are born with about 5 million hair follicles from where hair will grow out.

Hair has 2 main structures: the follicle and the shaft. The part of the hair that is above the surface of the skin is called the shaft. It consists of 3 layers of a hard protein: keratin. This protein consists of dead cells, meaning the hair that we see is not a living structure. That is why it’s not painful to get a haircut.

Human hair can be divided into 2 types.

  • Vellus hair is short and thin hair on the body.
  • Terminal hair is longer and thicker. This includes the hair on the head, eyelashes, eyebrows, belly hair, and so on.

The ratio of these types of hair on the human body is influenced by many factors, including gender and age. For example, children mostly have vellus hair. Terminal hair covers about 30% of the body in women and about 90% in men.

The phases of hair growth

To better understand the process of hair growth, you need to know its phases.

  • Anagen is the active phase of hair growth, during which the cells in the hair root divide rapidly. Each hair on your body grows from a separate hair follicle. The cells the hair is made of are formed at the root of the hair shaft, located inside the follicle. Over time, new hair cells push the old ones out. During this process, the cells die and become hair.
  • Catagen is the next phase of hair growth and is considered transitional. At any given time, about 3% of all our hair is in this phase. This period lasts about 2-3 weeks. Hair growth stops, the follicle shrinks and disintegrates to renew itself.
  • Telogen is the resting phase. It usually accounts for 6 to 8% of all our hairs. This phase lasts about 100 days for the scalp and even longer for other hair. During telogen, the hair follicle is completely at rest. Toward the end of this phase, the hair begins to fall out. The phase when the hair falls out is called the exogen phase. Within a couple of weeks, a new hair will form and the follicle will return to phase 1.

Why does body hair have different lengths?

The anagen phase is responsible for hair length. Our scalp hair remains in this phase for quite a long time — from 2 to 6 years. This is why it grows so long.

If you find it difficult growing your hair beyond a certain length, it’s likely that your hair has a short anagen phase. People with very long hair, as a rule, have a long active growth phase.

The hair on our body, including eyelashes, eyebrows, and hair on the legs and arms, has a very short anagen phase of 30 to 45 days. Most of the time, it is in the telogen phase. This is why it’s much shorter than the hair on the head.

On average, hair grows from 0.2 to 0.7 inches per month. All hair grows at different rates.

  • Scalp hair — 0.014 inches per day
  • Eyebrows and eyelashes — 0.006 inches per day
  • Beard hair — 0.015 inches per day

Hair loss — is it normal?

Human hair doesn’t grow simultaneously. Even neighboring follicles can be in different phases. This is why our hair falls out daily, but we don’t go bald. A person has about 100,000 hairs on their head, some of them are ready to fall out, while others are just entering the phase of active growth.

Not only scalp hair tends to fall out, we lose it all over the body. It’s just that the hairs on the arms or legs are not as long and noticeable, so we often don’t see when they fall out.

Every day we lose 50-100 hairs. With age, the hair from some follicles stops growing, which is why old people have thinning hair.

Interesting facts about hair

  • Bone marrow is the only part of our body that grows faster than hair.
  • A fetus has all of its hair follicles formed by the 22nd week of pregnancy.
  • The only parts of the body where hair doesn’t grow are the lips, palms, and soles of the feet.
  • Male hair grows faster than female hair.
  • People with oval shaped follicles have curly hair, while people with round follicles have straight hair.
  • Hair grows fastest between the ages of 15 and 30.
  • In summer, hair grows faster.
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