| Hair: Life Cycle |
| Karen Marie Shelton |
| Revised Date: 01/17/07 - Original Publication Date: 6/23/00 |
Introduction
Depending on which expert you talk to, human hair has
a life cycle that lasts anywhere from one to seven
years. Some humans actually have hair that has
longer cycles, which explains why some people can grow
much longer hair than others.
The process of growing hair starts with the fetus.
Our first hair known as Lanugo hair which is
Latin for fine wool, begins to appear on the fetus
somewhere between 12 and 24 weeks.
Each hair lives for its predetermined life and then
dies and eventually falls out.
The Lanugo or very soft and fuzzy or downy
hair falls off shortly after birth and is replace with
hair that has more coarseness. Throughout our
lives human hair continues to evolve and change.
Every day anywhere from 50 to 150 hair may die but
new ones are constantly growing to take the place of the
dead hair to that hair loss is not usually noticeable
unless other factors are at play.
There are three recognized phases in the life cycle
of a hair. these include:
- Anogen Phase
- Telogen Phase
- Catogen Phase
Although most people experience consistent hair cycle
phases, depending on a variety of factors, the cycles
may not fall into the same consistency for all.
Anogen Phase - Hair Growth Phase
This is the period of new hair growth. The
average person, depending on age and other factors, will
experience a growth rate of 1/4 to 1/2 inches a month.
During the Anogen Phase the sebaceous glands are active.
Keratin and protein are being constantly
manufactured. During this cycle hair is being
slowly progressed upwards through the skin to its
predetermined natural length.
Depending on a variety of factors this cycle will
last anywhere from three to six years.
The majority of the hair on your head is in the
Anogen Phase.
Telogen Phase - Hair Growth Stops
This is the period when hair stops growing. The
sebacous glands become less active.
The Telogen Phase is only active for approximately 1%
of your hair.
Catogen Phase - Hair Shedding Phase
The sebaceous glands stop working completely and the
follicles shrink. After approximately three months
the hair falls out completely.
The Catogen Phase is always active for 14 to 14% of
your hair
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