Hair follicles develop from a complex series of interactions between different elements of the skin. Interestingly, not all hairs are actively growing at the same time – they actually go through distinct phases: growth, regression, and resting. The duration of each phase is dependent on several factors, including body location. For example, at any one time, 90% of the hairs on our head are in their growth or Anagen phase, compared to only 70% of the hair on our arms. During the regression or Catagen phase, the surrounding skin begins to absorb the hair bulb. Finally, the hair enters the Telogen or resting phase, at the end of which the hair falls out and the follicle begins to cycle again.

Age, ethnicity, medications, hormone levels, and body site influence the length, coarseness, and color of body hair. The amount and distribution of body hair is largely determined genetically. This may vary according to racial characteristics. How much hair you have depends upon how many hairs are in their active growth phase, and how long that phase lasts.

In the past, various methods were used to remove unwanted hair. Each of the following traditional methods, while variably effective, have distinct disadvantages when compared to laser hair removal.

• Shaving: Although a simple way to remove hair, shaving doesn’t affect the coarseness, thickness, growth rate, or cycle of unwanted hair. Shaving is only a transient solution and requires a constant commitment to maintaining a hair-free appearance.
• Tweezing: This is a tedious, painful, and impractical method for large areas.
• Waxing: This procedure can cover a large area at one time and results may last a month or more, but it is painful and can often cause allergic reactions and inflammation of the hair follicle.
• Electrolysis: This process involves inserting a needle into each individual hair follicle and applying an electric current. Expertly used, this can be successful in eliminating hair permanently. However, because you can treat only one hair follicle at a time, it is a tedious, time-consuming process. Electrolysis can sometimes lead to skin infections and scarring.

Laser hair removal is a method of removing unwanted hair, utilizing laser energy targeted to the hair follicle to cause thermal damage and prevent further hairs from growing.

The near-infrared laser light produced by the system passes through the skin’s surface and is preferentially absorbed by the pigment located in the hair follicle. The laser energy is absorbed by the hair follicle and converted into heat, which damages the hair’s ability to grow. The damaged hair root is then expelled or absorbed by the body.

Temporary hair loss almost always occurs after each laser treatment, regardless of hair color. However, the laser’s effectiveness for permanent hair reduction is strongly correlated with hair color. Darker hair is more effectively treated than light hair. Blonde or white-haired patients are unlikely to experience permanent reduction in hair, but hair loss in these patients can be maintained if desired, by treatment at approximately three-month intervals.

Laser hair removal works by disabling hairs that are in their active growth (Anagen) phase at the time of treatment. Since other hairs will enter the growth phase at different times, several treatments are necessary to disable all hair follicles in a given area.