using laser as hair removal

Laser and light-based methods, sometimes called phototricholysis or photoepilation, are now most commonly referred to collectively as "laser hair removal". One of the first published articles describing laser hair removal was authored by the group at Massachusetts General Hospital in 1998.

The efficacy of laser hair removal is now generally accepted in the dermatology community, and laser hair removal is widely practiced. Many reviews of laser hair removal methods, safety, and efficacy have been published in the dermatology literature

The primary principle behind laser hair removal is selective photothermolysis. Lasers can cause localized damage by selectively heating dark target matter in the area that causes hair growth while not heating the rest of the skin. Light is absorbed by dark objects, so laser energy can be absorbed by dark material in the skin (but with much more speed and intensity).

Hair removal lasers selectively target Melanin:
Melanin is considered the primary chromophore for all hair removal lasers currently on the market. Melanin occurs naturally in the skin (it gives skin and hair its color). There are two types of melanin in hair: eumelanin (which gives hair brown or black color) and pheomelanin (which gives hair blonde or red color). Because of the selective absorption of photons of laser light, only black or brown hair can be removed.

Both men and women seek laser hair removal services to have superfluous or unwanted hair removed. Laser is attracted to dark pigment and therefore works best with dark coarse hair. Light skin and dark hair are an ideal combination, but new lasers are now able to target dark black hair even in patients with dark skin.

Hair removal lasers have been in use since 1997 and the Food and Drug Administration approved it for “permanent hair reduction.” Laser hair removal has become extremely popular because of its speed and efficacy, although some of the efficacy is dependent upon the skill and experience of the laser operator, and the choice and availability of different laser technology at the clinic which is performing the procedure. Some will need touch-up treatments, especially on large areas, after the initial set of 3-8 treatments.

Several wavelengths of laser energy have been used for hair removal, from visible light to near-infrared radiation. The parameter of laser are:
· Argon: 488 or 514.5 nm (not used for hair removal anymore)
· Ruby: 694 nm (not used for hair removal anymore; not safe on most skin types)
· Alexandrite: 755 nm (most effective, but safest on light skin)
· Pulsed diode array: 810 nm (for light to medium type skin)
· Nd:YAG: 1064 nm (for darker skin)

Spot size, or the width of the laser beam, affects treatment. Theoretically, the width of the ideal beam is about four times as wide as the target is deep. Hair removal lasers have a round spot about the size of your finger (8-18 mm). Larger spot sizes help make treatments faster and more effective.

Fluence or energy level is another important consideration. Fluence is measured in joules per square centimeter (J/cm²). It's important to get treated at high enough settings to cause permanent damage to the hair follicles.
· Clear gel: usually chilled
· Contact cooling: through a window cooled by circulating water
· Cryogen spray: immediately before/after the laser pulse
· Air cooling: forced cold air at -34 degrees C (Zimmer Cryo 5 unit)
Multiple treatments, usually 3-8, have been shown in numerous studies to provide long-term reduction of hair.

The number of sessions depends on various parameters, including the area of the body treated, skin color, coarseness of hair, and gender. In addition, since hair grows in several phases and laser can only affect the currently actively growing follicles, several sessions are needed to kill hair in all phases of growth.

In general, it is necessary to foresee between 3 - 8 treatment sessions. Coarse dark hair on light skin is easiest to treat. Finer hair and hair on darker skin is harder to treat and may require more treatments. Certain areas (notably men's and women's faces) may require considerably more treatments to achieve desired results.

Usually, treatments are spaced 3-12 weeks apart to start, although the spacing depends upon individual response to treatment. Treatment spacing also depends on area treated as hair cycles vary based on the body part. For example, women’s faces usually require more frequent treatments, whereas backs and legs require less frequent treatments.

Hair removal lasers are effective treatment for pseudofolliculitis barbae (commonly called ingrown hairs or "shaving bumps"). For darker skin patients with black hair, the long-pulsed Nd:YAG laser with a cooling tip can be safe and effective when used by an experienced practitioner.

The costs of laser hair removal vary by U.S. region, and by surface area and location treated. Laser hair removal should be used cautiously, if at all, by patients in the following categories: Recently acquired dark tan; fine, light hair in people of color; blonde or red hair in areas with tan skin; patients who cannot afford or do not have the time for multiple sessions, because one treatment is rarely adequate.