Rio Salon Laser Manual page 7

It is important to understand the normal hair growth cycle to
understand how the Salon Laser Scanning Hair Remover works.
The hair follicle is an anatomical structure which evolved to
produce and push out a hair shaft. Hair is made up of proteins
called keratins. Human hair grows in a continuous cyclic
pattern of growth and rest known as the "hair growth cycle."
Three phases of the cycle exist:
Anagen = active growth phase
Catagen = degradation phase
Telogen = resting phase
Periods of growth (anagen) between two and seven years, are
followed by a period in which the follicle is totally degraded.
The resting phase (telogen) then begins and lasts between
T H E HA IR GR O WT H C YCLE
six weeks and six months. Shedding of the hair occurs only
after the next growth cycle (anagen) begins, and a new hair
shaft begins to emerge. 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. These hairs will regrow. The percentage of follicles
in the resting phase (telogen) will vary at any time depending
on the body area. It is also important to note that a variety of
factors can affect the hair growth cycle and cause temporary
or permanent hair loss (alopecia) including medication,
radiation, chemotherapy, exposure to chemicals, hormonal
and nutritional factors, thyroid disease, generalised or local
skin disease, and stress.
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