The
hair growth cycle
Each individual hair is formed inside a hair bulb deep in a
hair follicle. The follicle is a tiny but powerful factory,
which throughout many people's lifetime hardly ever stops working.
From a baby's birth for many decades, as much as a century in
some people, the follicle continues to produce hairs. Each hair
grows for many years: during this time it will be shampooed,
conditioned, cut, blown dry, exposed to sun and wind, colored
or bleached or permed. None of these treatments affects the
growth of the hair in the hair bulb, even though some may seriously
damage the hair shaft. Finally the hair spontaneously falls
out. The follicle rests for a little while, and then starts
to produce yet another new hair. This is the hair cycle.
You need to know about the hair cycle in order
to understand many of the problems people have with their hair.
These can range from the sudden appearance of hairless patches
to complete baldness in men, and sometimes in women too.
Stages of the hair cycle
Between starting to grow and falling out years later, each hair
passes through three distinct stages. These are so important
that they have been given special names: anagen (the
growing phase), catagen (the intermediate phase) and
telogen (the shedding phase).
We shall look at these three stages in turn. |
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Anagen (the growing phase)
The anagen phase of a new hair starts at the moment it
begins to grow. At that time there is very active growth in
the hair bulb. This usually
Naturally
blond hair: this lady's anagen phase lasts for about
four years |
