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| We're
born with all our hair follicles already in place. While
some may change in size over time, we don't develop any
new ones after birth. As
adults, we have about 100,000 individual strands of
hair. It's completely normal to lose some - 40 to 100
strands - every day. Normal hair loss is the result
of the growth cycle of the follicles, similar to an
'on-off' system. This means that when an old hair 'dies',
the growing phase starts again for a new hair to replace
it. The hair growth cycle has three different phases: |
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The
anagen phase is the growing phase, or the 'on' phase which
lasts for an average of approximately 1,000 days in the
human scalp, but can range from two to six years. During
the anagen phase, hair cells proliferate rapidly. The
hair shaft grows in diameter and the hair reaches maximum
length. |
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The
catagen phase lasts only one to two weeks. It is the transitional
or regressive phase, before the resting phase begins.
It is essentially when the hair stops growing. |
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The
telogen is the final resting stage, or 'off' phase. |
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| When
the old hair is in the telogen phase, activity in the
hair follicle is renewed. A new hair in the anagen phase
develops and forces the old telogen hair out. This is
when hairs are lost and you might notice them in the bath
or in your brush or comb.
At
any one time, around 90 per cent of most people's hair
follicles are in the 'growing' anagen phase and approximately
10 per cent are in the 'resting', or telogen phase.
Noticeable hair loss is usually caused by a short anagen
phase and a particularly long telogen phase. But
in women whose hair is thinning, the follicles have
shrunk, resulting in finer hairs, barely visible to
the naked eye. Eventually the hair follicles shut down
completely. Reference:
Adrogenetic Alopecia. The Growth and Loss of Hair, The
Upjohn Company, 1989.
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| Causes
of Hair Loss |
| There
are lots of reasons why you might start losing more hair...
including pregnancy, a medical disorder, prescribed
medication, poor nutrition, bad hair care techniques or
stress caused by emotional anxiety, surgery or prolonged
illness.
But the most common
type of sustained hair loss in women is hereditary hair
loss(or common hair loss) (the technical name is diffuse alopecia), which accounts
for about 95 per cent of cases.
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