The average human scalp contains between 100,000 and 150,000
hairs. These grow from the follicle or root, underneath the skin.
The hair is 'fed' by blood vessels at the base of the follicle,
giving it the nourishment it needs to grow. Each hair goes through
a growth cycle independent of the other hairs on the scalp.
At any given time, approximately 90% of the hairs on the head
are in the growth phase, or 'Anagen', while the
other 10% are in the resting phase, or 'Telogen'.
The Anagen phase lasts between 2-6 years, after which the follicle
goes through a brief transition phase ('Catagen')
and enters the resting phase, which lasts from 2-4 months. After
the Telogen phase, the hair falls out naturally and is replaced,
returning the hair to the Anagen phase. 'Shedding' occurs only
after the return to the Anagen phase and on average 50-100 Telogen
hairs are shed every day. This is normal hair loss and accounts
for the hair loss seen every day in the shower and with hair combing.
|
