Laser hair removal
From Wikipedia, the free encyclopedia
Epilation performed by laser was performed experimentally for about 20 years before it became commercially available in the mid 1990s. Laser and light-based methods are sometimes called phototricholysis or photoepilation.
In addition to lasers, some light-based epilators use a xenon flash lamp which emits full-spectrum intense pulsed light (IPL) . Treatment with this device is sometimes popularly referred to as laser hair removal, though the device is not a laser per se.
Mechanism of action
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). This dark target matter, or chromophore, can be naturally-occurring or artificially introduced.
Hair removal lasers selectively target one of three chromophores:
Carbon, which is introduced into the hair follicle by rubbing a carbon-based lotion into the skin following waxing (this lotion is an "exogenous chromophore"). When irradiated by a Q-switched Nd:YAG laser, the carbon causes a shock wave capable of mechanically damaging nearby cells. This method has been abandoned since it does not cause permanent loss. (It has been replaced with the long-pulsed Nd:YAG laser which targets endogenous melanin in the follicle.)
Hemoglobin, which occurs naturally in blood (it gives blood its red color). It preferentially absorbs wavelengths from argons, and to a lesser extent from rubies, alexandrites, and diodes. It minimally absorbs the Nd:YAG laser wavelength. Hemoglobin is not a primary target for laser hair removal.
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. Hair removal is commonly done on lip, chin, ear lobe, shoulders, back, underarm, abdomen, buttocks, pubic area, bikini lines, thighs, face, neck, chest, arms, legs, hands, and toes.
Laser is attracted to dark pigment and therefore works best on pale skin and dark coarse hair. The closer you are to this combination (i.e. the lighter the skin and the more coarse and dark the hair), the better the results will generally be after proper treatments.
Hair removal lasers have been in use since 1997 and the Food and Drug Administration approved it for “permanent reduction.” They permanently disable hair follicles, however you have to remember that laser hair removal doesn’t work in the same way on everyone and doesn’t remove 100% of the hair in an area. Generally, this means that you shouldn’t expect to remove every single hair from an area, although you can remove the majority of it (given you are a good candidate with light/medium skin and dark at least somewhat coarse hair). Most people need to follow up with electrolysis treatments for any remaining hairs to achieve complete clearance, if desired, as the remaining hairs become too sparse and fine for laser to target. Some will also need touch-up treatments about once a year, especially on large areas, after the initial set of 6-8 treatments for any new growth your body may develop with age on certain areas. 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. Keep in mind that it's hard to judge whether someone’s lack of results is due to a potential underlying medical condition that causes continuous growth and makes it seem like laser isn’t working, if the treatment wasn't performed properly, or whether for some people it just doesn't work for currently unknown reasons. In essence, you can’t determine what your personal results with be like unless you try it. Results depend on many variables involved, including the tech's experience, type of laser used, how settings are set, etc. It is recommended to start with one smaller area and see how your hair reacts before committing to an expensive set of treatments on many areas at once.
Electrolysis is an alternative permanent hair removal method that has been used for over 125 years. It involves treating one hair at a time and is a good option for smaller areas (like eyebrows or upper lip) where precision is necessary. It does take considerably more treatments compared to laser to complete a large area, but is an option as well. At this time, it is as the only permanent option for very fine and light-colored hair.
Laser parameters that affect results
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)):
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 only safe on light skin)
Pulsed diode array: 810 nm (for light to medium type skin)
Nd:YAG: 1064 nm (for darker skin)
Pulsewidth is an important consideration. It has been observed in some published studies that longer pulsewidths are safer in darker skin. Wavelength is a critical factor. Longer wavelengths are safer in darker skin. However, shorter wavelengths are more effective in removing hair.
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.
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.
Epidermal 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
Cryogen spray: immediately before/after the laser pulse
Air cooling: forced cold air at -34 degrees C (Zimmer Cryo 5 unit)
Multiple treatments, usually 6-8, have been shown in numerous studies to provide long-term reduction of hair. Current parameters suggest a series of treatments spaced at 8-12 weeks apart for most areas, with face requiring shortest intervals and legs and back requiring longest intervals. These parameters are based on length of hair growth cycles on various areas.
Number of sessions
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 6 to 8 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 and men's backs, upper arms, and shoulders) may require considerably more treatments to achieve desired results.
It's important to note that laser does not work on light hair and very fine and vellus hair. Electrolysis is the only permanent solution for those types of hair.
Intervals between sessions
Usually, treatments are spaced 8-12 weeks apart to start, and can gradually move to 10-16 weeks apart after the initial 2-3 treatments. Instead of following an arbitrary schedule, you should wait until you have experienced shedding of the treated hairs, which should complete within 2-3.5 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, women’s faces 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 "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.
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.
From Wikipedia, the free encyclopedia
Epilation performed by laser was performed experimentally for about 20 years before it became commercially available in the mid 1990s. Laser and light-based methods are sometimes called phototricholysis or photoepilation.
In addition to lasers, some light-based epilators use a xenon flash lamp which emits full-spectrum intense pulsed light (IPL) . Treatment with this device is sometimes popularly referred to as laser hair removal, though the device is not a laser per se.
Mechanism of action
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). This dark target matter, or chromophore, can be naturally-occurring or artificially introduced.
Hair removal lasers selectively target one of three chromophores:
Carbon, which is introduced into the hair follicle by rubbing a carbon-based lotion into the skin following waxing (this lotion is an "exogenous chromophore"). When irradiated by a Q-switched Nd:YAG laser, the carbon causes a shock wave capable of mechanically damaging nearby cells. This method has been abandoned since it does not cause permanent loss. (It has been replaced with the long-pulsed Nd:YAG laser which targets endogenous melanin in the follicle.)
Hemoglobin, which occurs naturally in blood (it gives blood its red color). It preferentially absorbs wavelengths from argons, and to a lesser extent from rubies, alexandrites, and diodes. It minimally absorbs the Nd:YAG laser wavelength. Hemoglobin is not a primary target for laser hair removal.
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. Hair removal is commonly done on lip, chin, ear lobe, shoulders, back, underarm, abdomen, buttocks, pubic area, bikini lines, thighs, face, neck, chest, arms, legs, hands, and toes.
Laser is attracted to dark pigment and therefore works best on pale skin and dark coarse hair. The closer you are to this combination (i.e. the lighter the skin and the more coarse and dark the hair), the better the results will generally be after proper treatments.
Hair removal lasers have been in use since 1997 and the Food and Drug Administration approved it for “permanent reduction.” They permanently disable hair follicles, however you have to remember that laser hair removal doesn’t work in the same way on everyone and doesn’t remove 100% of the hair in an area. Generally, this means that you shouldn’t expect to remove every single hair from an area, although you can remove the majority of it (given you are a good candidate with light/medium skin and dark at least somewhat coarse hair). Most people need to follow up with electrolysis treatments for any remaining hairs to achieve complete clearance, if desired, as the remaining hairs become too sparse and fine for laser to target. Some will also need touch-up treatments about once a year, especially on large areas, after the initial set of 6-8 treatments for any new growth your body may develop with age on certain areas. 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. Keep in mind that it's hard to judge whether someone’s lack of results is due to a potential underlying medical condition that causes continuous growth and makes it seem like laser isn’t working, if the treatment wasn't performed properly, or whether for some people it just doesn't work for currently unknown reasons. In essence, you can’t determine what your personal results with be like unless you try it. Results depend on many variables involved, including the tech's experience, type of laser used, how settings are set, etc. It is recommended to start with one smaller area and see how your hair reacts before committing to an expensive set of treatments on many areas at once.
Electrolysis is an alternative permanent hair removal method that has been used for over 125 years. It involves treating one hair at a time and is a good option for smaller areas (like eyebrows or upper lip) where precision is necessary. It does take considerably more treatments compared to laser to complete a large area, but is an option as well. At this time, it is as the only permanent option for very fine and light-colored hair.
Laser parameters that affect results
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)):
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 only safe on light skin)
Pulsed diode array: 810 nm (for light to medium type skin)
Nd:YAG: 1064 nm (for darker skin)
Pulsewidth is an important consideration. It has been observed in some published studies that longer pulsewidths are safer in darker skin. Wavelength is a critical factor. Longer wavelengths are safer in darker skin. However, shorter wavelengths are more effective in removing hair.
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.
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.
Epidermal 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
Cryogen spray: immediately before/after the laser pulse
Air cooling: forced cold air at -34 degrees C (Zimmer Cryo 5 unit)
Multiple treatments, usually 6-8, have been shown in numerous studies to provide long-term reduction of hair. Current parameters suggest a series of treatments spaced at 8-12 weeks apart for most areas, with face requiring shortest intervals and legs and back requiring longest intervals. These parameters are based on length of hair growth cycles on various areas.
Number of sessions
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 6 to 8 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 and men's backs, upper arms, and shoulders) may require considerably more treatments to achieve desired results.
It's important to note that laser does not work on light hair and very fine and vellus hair. Electrolysis is the only permanent solution for those types of hair.
Intervals between sessions
Usually, treatments are spaced 8-12 weeks apart to start, and can gradually move to 10-16 weeks apart after the initial 2-3 treatments. Instead of following an arbitrary schedule, you should wait until you have experienced shedding of the treated hairs, which should complete within 2-3.5 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, women’s faces 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 "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.
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.
