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Laser hair removalEpilation by laser was performed experimentally for about 20 years before it became commercially available in the mid 1970s. Intense Pulsed Light (IPL) epilators, though technically not a laser, use xenon flash lamps that emit full spectrum light. 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.[1][2] 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.[3] The primary principle behind laser hair removal is selective photothermolysis (SPTL).[4] Lasers can cause localized damage by selectively heating dark target matter, (melanin), in the area that causes hair growth, (the follicle), 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). This dark target matter, or chromophore, can be naturally-occurring or artificially introduced. 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. Hair removal lasers have been in use since 1997 and has been approved for "permanent hair reduction" in the United States by the Food and Drug Administration (FDA).[6] The FDA's use of the word "permanent" here is not without controversy. Indeed, many patients experience near complete regrowth of hair on their treated areas in the years following their last treatment. 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. It has also been observed that some people seem to be non-responders – this is not confirmed and reasons are not known, and may in fact be due to lack of skill on the part of many laser operators and/or the type of machine and settings they are using





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