How Does Laser Work?

The laser works by a principle called Selective Photothermolysis. The laser is pulsed (turned on) for a millisecond emitting a beam of light on to the skin. The light energy passes harmlessly through the skin, but is absorbed by the pigment in the hair follicles and hair shafts that are in the active growth phase. By absorbing this laser energy, the hair follicles are disabled, impairing their ability to grow. This damage causes delayed re-growth of the hair, and in some cases permanent destruction of many of the hair follicles. Unlike electrolysis, which kills one hair follicle at a time, the laser reaches and treats hundreds of follicles at a time. A system for cooling the skin will be used to remove heat as it leaves the follicles and should ensure a comfortable treatment, resulting in virtually painless hair removal. Lasers allow for the safe treatment of darker skin and they are very effective in treating pseudofolliculitis barbae, a bacterial infection commonly seen in darker hair-bearing skin.

Some procedures will require the patient to bring a responsible adult driver. Treatment time will depend upon the area to be treated.

The numbers of sessions vary for each individual. Usually, laser hair removal requires 3 to 6 sessions, depending upon the skin type and hair color.

While some areas of the body are more sensitive than others, most patients report manageable discomfort. For the more sensitive patients, anesthetic creams can be applied prior to the treatment.

Immediately after the treatment the skin will look pink and slightly swollen, similar to sunburn. This will subside within an hour or two and the skin will return to normal.

One treatment may zap thousands of hairs. But one treatment usually isn't enough. Because hair grows in staggered cycles, and laser light affects only actively growing hair, you must usually undergo multiple treatments over weeks and months to achieve smoother-looking skin. If you have light skin, your doctor may use a ruby, alexandrite or diode laser. If you have darker skin, an Nd:YAG laser may be used. So far, the Nd:YAG laser is the only one that's been proved safe and effective for all skin types. Lasers may have a cooling device on their tips to minimize skin damage.

During the procedure, your doctor presses a hand-held laser to your skin, and activates it for a fraction of a second. The laser light passes through your skin's surface to tiny sacs called hair follicles. Each follicle contains a bulb that germinates a hair shaft. When light reaches your hair follicles, it temporarily generates enough heat to destroy the follicles and bulbs. If the procedure is successful, your old hair falls out and new hair doesn't grow back.

Hair Phases

Adult hair has 3 distinct phases of development: anagen, catagen, and telogen. As hairs progress through these phases, they are affected differently by treatment with laser-assisted hair removal.

• Anagen is the phase in which active hair growth occurs. Follicular matrix cells are actively producing cells that will make up the growing hair. The growing hair consists of all 4 histologic divisions in anagen.
  
• In catagen (the regression phase), matrix cells degenerate and the bulb begins to atrophy, causing the hair follicle to shrink.
  
  
• Telogen is the final resting phase of the hair follicle. Growth of the hair has stopped, and the follicle becomes inactive. Now the follicle contains only the superficial components, the infundibulum and the isthmus. During telogen, the hair is released from its attachment to the skin and sloughs away. The process begins again in anagen to form a new hair.

The length of time spent in each phase depends upon the location of the hair. On the scalp, hair follicles spend up to 10 years in anagen, but on the trunk, brow, and limbs, anagen lasts no longer than 6 months. Catagen lasts only 2-3 weeks, and telogen lasts from 3-4 months.

Up to 90% of hairs in a given body location can be in the anagen phase at a given time. This fact becomes important because only hairs in the anagen phase of development are susceptible to injury during a session of laser-assisted hair removal. Thus, multiple treatments are necessary to treat all hair follicles on a given body surface area.

2009 (c) GuideToHairRemoval.com, Inc. - All Rights Reserved