About hair

Human’s body is completely covered with hair except on the palms, feet and lips. On some parts of one's body hairs are visible and grow rather quickly, whereas on other parts they are almost invisible.

How many hairs do we have?

Everyone has on average around 100,000 hairs and on some people – up to 150,000.

Each hair root grows about 20 new hairs during a person's lifetime, each of which will grow for many years and can reach about one meter in length. Each hair finally falls out and new hair starts to grow in its place.

The hair growth cycle

There are three stages of hair growth:
1. Growth phase – anagen.
2. Destruction phase – catagen.
3. Resting phase – telogen.

At the end of growth phase (1000 days and more) is destruction phase (10 days and more). During this period the follicle completely collapses, leading to the resting phase (100 days and more). Following the resting phase the hair falls out and the growth phase begins again.

So, it's normal for a human to lose about 60–100 hairs a day, after which the fallen hairs start to grow again. Generally, around 10% of human hairs are in the resting phase at any one time.

Many factors can influence the hair growth cycle and cause the loss or even accelerated growth of hair. These factors can include: medicines, chemotherapy, hormonal processes and other.

Hair roots – follicles

The follicular unit is a hair bearing structure containing from one to four hair bulbs, each of which is able to produce hair.

Pulling out a hair from its root results in the next growth cycle.

Over the years, the number of roots capable of producing hair declines naturally. Thinning hair is more obvious on the vertex – on the top of the head. In time, some roots start to produce thin, pigmentless hairs, barely visible to the human eye. If you look hard enough, you can find many such thin hairs on the balding area of a balding head.

Haircutting

Contrary to common belief, haircutting does not stimulate growth and does not make hairs thicker.

Nor does the shaving of the head, body or legs result in more intensive hair growth nor does it make hair rougher. It only appears to be so.

The thickness of hair depends only on ethnicity and personal physiological characteristics. There is nothing capable of influencing the thickness of hair.

Physical effect on hair

Hairs in the resting phase can easily fall out under physical stress. Therefore, when you start to wash or to comb your head intensively, you will see hairs falling out. You may think that this is due to a new shampoo or hairbrush, however this is not the case. Those hairs would have fallen out in any case, but slightly later. New hair will start to grow back after the old hair falls out.

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