The Science of Laser Hair Removal
Physiology of Hair

Laser hair removal success is dependent upon the natural physiology of hair.  Because lasers can only treat hair in the anagen (active) phase, the number of treatments needed for different body areas can vary.  Below is a chart of hair growth cycles on different parts of the body.

 Growth Cycle Chart

Body area

% Anagen

% Telogen

Scalp

85

13

Beard (Chin)

70

30

Upper Lip

65

35

Underarm

30

70

Bikini

30

70

The following chart is designed to show the duration of the growth cycles.  The total duration of growth cycles is also highly variable.  One may get a better idea of how to space treatments apart based on this chart.  For example, treatments for arms may be spaced closer together than back treatments.

 Duration of Growth Cycle (in Months)

Body Area

Anagen

Telogen

Total Cycle

Back

3-6

3-6

6-12

Leg/Thigh

3-6

3-6

6-12

Arm

1-2

3-5

4-7

Underarm

3-4

2-3

5-7

Upper lip

3-4

1-2

4-6

Bikini

2-3

3-4

5-7

Laser hair removal also depends on different characteristics of hair, as mentioned earlier, such as coarseness, depth of the follicle, and color.  An experienced physician well-trained in laser technology should be able to achieve high success rates with a great safety record.

Hypertrichosis is excessive hair growth that is not hormone dependent (androgen).  This can occur over a small area or generalized over larger areas.  More commonly, hirsutism occurs.  In women, this usually occurs because of excessive androgen production.  Fine vellus hairs, or “peach fuzz” become terminal hairs.  For example, a woman may develop male patterns such as facial hair.  This may be normal in some women, but in others it may be linked to serious medical conditions, such as polycystic ovarian syndrome and numerous tumors.  The experienced physician who treats you should be able to refer you to a specialist if one of these conditions is suspected.  Hirsutism can also be caused by medications, such as birth control pills and steroids.  A thorough medical and medication history should be evaluated by an experienced physician.

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The Science of Laser Hair Removal