Laser hair removal
From AssaraWiki
Epilation in the form of laser hair removal was performed experimentally for about 20 years before it became commercially available in the mid 1990s. 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".
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. 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).
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How laser hair removal works
The primary principle behind laser hair removal is selective photothermolysis (SPTL). Lasers can cause localized damage to hair follicles by selectively heating dark target matter, (melanin), in the area that causes hair growth, (the follicle), while not heating the rest of the skin.
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, it is rather difficult to use laser hair removal on exclusively blonde, red, or grey hairs effectively.
Both men and women seek laser hair removal services to have superfluous or unwanted hair removed. Hair removal is commonly done on lip, chin, ear lobe, shoulders, back, underarm, abdomen, buttocks, pubic hairs, bikini lines, thighs, facial hair, neck, cleavage, chest, arms, legs, hands, and toes.
Laser works best with dark coarse hair. Light skin and dark hair are an ideal combination, but new lasers, specifically those that utilize the Nd:YAG laser medium, are now able to target dark black hair even in patients with dark skin.
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.
Comparison with electrolysis
Electrolysis is another hair removal method that has been used for many years. At this time, it is the only permanent option for very fine and light-colored hair.
A study conducted in 2000 at the ASVAK Laser Center in Ankara, Turkey comparing alexandrite laser and electrolysis for hair removal on 12 patients concluded that laser hair removal was 60 times faster, less painful and more reliable than electrolysis.
Laser parameters that affect results
Wavelength
Several wavelengths of laser energy have been used for hair removal, from visible light to near-infrared radiation. These lasers are usually defined by the lasing medium used to create the wavelength (measured in nanometers (nm)). An experienced practitioner will select the appropriate laser wavelength based, among other things, on the patient's skin type and color.
Argon: 488 or 514.5 nm (no longer used for hair removal)
Ruby: 694 nm (no longer used for hair removal; not safe on most skin types as it frequently produces side effects such as pigmentary changes (lightening or darkening of the skin) or worse for patients of all but very white skin.
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; Yag is capable of treating all six skin colors.)
Pulsewidth
Pulsewidth is an important consideration. It has been observed in some published studies that longer pulse widths may be safer for darker skin.
Spot size
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
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.
Repetition Rate
Repetition rate is believed to have a cumulative effect, based on the concept of thermal relaxation time. Shooting two or three pulses at the same target with a specific delay between pulses can cause a slight improvement in the heating of an area. This may increase the "kill rate" for each treatment slightly.
Skin cooling
Skin cooling has been determined to allow higher fluences and reduce pain and side effects, especially in darker skin. Four types of cooling have been developed:
Clear gel: usually chilled
Contact cooling: through a window cooled by circulating water or internal cryogen.
Cryogen spray: immediately before/after the laser pulse
Air cooling: propelled highly chilled air
Number of sessions
Multiple treatments, usually 5-7, but as many as 12, depending on the type of hair and skin color have been shown in practice 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 sex. Coarse dark hair on light skin is responds best to treatments. Finer hair and hair on darker skin is may require more treatments than coarse hair. Laser hair removal is generally less effective on light hair and very fine and vellus hair. Certain areas (notably men's and women's faces) may require considerably more treatments to achieve desired results.
In addition, since hair grows in a hair growth cycle, (anagen, telogen, catagen), and laser hair removal is most effective on the currently active growing follicles, (anagen), several sessions are usually needed to prevent all further hair growth.
Intervals between sessions
Current parameters suggest a series of treatments spaced at 4–6 weeks apart for most areas, although the timing of treatments has still not been standardized. Usually, the spacing depends upon individual response to treatment. For best results, you should wait until you have experienced shedding of the treated hairs, which should complete within 1-2 weeks, and see enough hair come in after the hair-free period to have another treatment. Treatment spacing also depends on area treated as hair cycles vary based on the body part. For example, facial hair usually require more frequent treatments, whereas backs and legs require less frequent treatments.
Other uses
Hair removal lasers are effective treatment for pseudofolliculitis barbae (commonly called ingrown hairs or "razor 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.
They have recently been reported as helpful treatment for pilonidal cysts, since they eliminate the ingrown hairs that produce the troublesome foreign body reactions in this congenital malady.
Risks
Risks include the chance of burning the skin or discoloring dark skin with the laser, hypopigmentation (white spots), flare of acne, swelling around the follicle, scab forming, and purpura. These risks are normally highly diminished by the selection of a highly-trained and experienced laser hair removal practitioner, using the appropriate laser for the client's skin type.
