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Hair is formed at the base of a hair follicle.
A follicle is a structure resembling a
pouch that is located below the skin.
What we usually call hair is in reality
the hair shaft, which is nothing but the
keratinized, hardened tissue that grows
from a follicle, which is where hair growth
is initiated.
Our head contains thousands of such hair follicles. However, all of
them are not active at the same time. It has been observed that not
more than 80% of our follicles are producing hair growth at any one
time. The remaining 20% of the follicles are asleep or dormant.
When our inactive or dormant hair follicles
start working again, they push out an
old hair while producing a new one.
Our hair
grows from the follicle at an average
rate of one-half inch every month. The
hair growth continues for a period varying
between four and seven years, after
which there sets in a ‘resting’
phase. After this resting phase, it
is time for the hair to fall out. As
a hair falls out, a new hair grows in
its place after a gap of three weeks
to three months. There are chances of
us losing 50 to 100 hairs in any day.
Some of us lose even more than that,
not to regrow
hair back again.
Hair grows differently from person to person, depending on age,
weight, metabolism, hormones, ethnicity, medications, and some other
factors. However, our hair growth effectively covers three distinct
phases: anagen, catagen and telogen. The anagen phase is also called
the active growth phase. This phase continues for several years.
At any given time, the major portion (85%) of our body hair is found
to be in this phase.
During this anagen phase, the hair has
an abundance of melanin. The catagen
or the regressive phase lasts for a
period of nearly two weeks, during which
the hair stops growing but is not yet
shed. It has been observed that about
3 - 4% of our body hair is in this phase
at any given time. The telogen phase
or the resting phase continues for 5
- 6 weeks, at the end of which the hair
falls out and a new hair begins to take
shape. Nearly 10-13% of our body hair
is in this phase at any given time.
There is an extensive
loss of hair when more hair enters
and stay in this phase. Research works
have established that the shock caused
to the human system by stress and sickness
can result in a larger percentage of
hair staying in the resting phase, leading
to reduced active hair
regrowth along with an accelerated
period of loss of hair.
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