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laser hair removal

Anchor 20

A little on Laser hair removal


Laser hair removal is the process of removing unwanted hair by means of exposure to pulses of laser light that destroy the hair follicle.  It had been performed experimentally for about 20 years before becoming commercially available in the mid-1990s.  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 accepted in the dermatology community, and laser hair removal is widely practiced in clinics, and even in homes using devices designed and priced for consumer self-treatment.


But, the Laser being used by Dr.Schoenfeld is not the “run of the mill” laser, which some Laser Hair removal clinics offer, and patients are well advised to compare the different laser types before committing to a treatment. We have the latest technology available and the results speak for themselves. I can speak from personal experience!


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 (SPTL), the matching of a specific wavelength of light and pulse duration to obtain optimal effect on a targeted tissue, with minimal effect on surrounding tissue, so as to avoid “collateral damage”.  Lasers can cause localized damage by selectively heating dark target matter, the hair follicle where the hair originates from, 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.  Melanin is considered the primary chromophore for all hair removal lasers currently on the market. Melanin occurs naturally in the skin, and gives skin and hair their color.


There are two types of melanin in hair. Eumelanin gives hair brown or black color, while pheomelanin gives hair blonde or red color.  Because of the selective absorption of photons of laser light, only black or brown hair can be removed. Laser works best with dark coarse hair. Light skin and dark hair are an ideal combination, being most effective and producing the best results.


Hair removal lasers have been in use since 1997 and have been approved for "permanent hair reduction" in the United States by the Food and Drug Administration (FDA).


Under the FDA's definition, "permanent" hair reduction is the long-term, stable reduction in the number of hairs re-growing after a treatment regime. Indeed, many patients experience complete regrowth of hair on their treated areas in the years following their last treatment. This means that although laser treatments with these devices will permanently reduce the total number of body hairs, they will not result in a permanent removal of all hair.


Laser hair removal has become popular because of its speed and efficacy, although some of the efficacy is dependent upon the skill and experience of the laser operator as well as the choice and availability of different laser technologies used for the procedure.  Some will need touch-up treatments, especially on large areas, after the initial set of 3-8 treatments.


It has also been noted that some people are "non-responders" – this occurs when the incorrect device is being used, the device parameters are too low or the patient is simply not a good candidate for treatment.


Preparing for you Laser Hair Removal session


The ALMA Hair removal system is virtually painless so there is no need for numbing creams or pain killers.  It is also not necessary for you to grow the hairs before you come for treatment, although you may want to allow some growth to occur before your first consultation so that the extent of the hair growth can be seen and noted by our Laser therapist. After that, you simply shave the night before you come in.


DO NOT WAX or PLUCK the hairs prior to treatment, as this will render the Laser ineffective!  Merely shave the hair the night before you come for laser treatment. No need to suffer embarrassment as you grow the hairs out!


Number of sessions


Hair grows in several phases (anagen, telogen, catagen) and a laser can only affect the currently active growing hair follicles (early anagen). Hence, several sessions are needed to kill hair in all phases of growth.  Multiple treatments depending on the type of hair and skin color have been shown to provide long-term reduction of hair.  Most patients need a minimum of seven treatments.


Current parameters differ from device to device but manufacturers and clinicians generally recommend waiting from three to eight weeks between sessions, depending on the area being treated.  The number of sessions depends on various parameters, including the area of the body being treated, skin color, coarseness of hair, reason for hirsutism, and sex.


Coarse dark hair on light skin is easiest to treat. Certain areas (notably men's faces) may require considerably more treatments to achieve desired results.

Laser does not work well on light-colored hair, red hair, grey hair, white hair, as well as fine hair of any color, such as vellus.


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.


Typically the shedding of the treated hairs takes about two to three weeks. These hairs should be allowed to fall out on their own and should not be manipulated by the patient for certain reasons, chiefly to avoid infections. Pulling hairs after treatment can be more painful as well.


Other uses


Hair removal lasers are effective treatment for pseudofolliculitis barbae, commonly called "ingrown hairs" or "shaving bumps".  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 malady.


Side effects and risks


Some normal side effects may occur after laser hair removal treatments, including itching, pink skin, redness, and swelling around the treatment area or swelling of the follicles (follicular edema). These side effects rarely last more than two or three days. The two most common serious side effects are acne and skin discoloration.


Some level of pain should also be expected during treatments.


Unwanted side effects such as hypo- or hyper-pigmentation or, in extreme cases, burning of the skin call for an adjustment in laser selection or settings. Risks include the chance of burning the skin or discoloration of the skin, hypopigmentation (white spots), flare of acne, swelling around the hair follicle (considered a normal reaction), scab formation, purpura, and infection. These risks can be reduced by treatment with an appropriate laser type used at appropriate settings for the individual's skin type and treatment area.


Some patients may show side effects from an allergy to either the  gel used with certain laser types, or to simply shaving the area too soon in relation to the treatment.


Rare side effects include blistering, scarring and skin texture changes.


Some more Laser physics for those who may be interested:


Several wavelengths of laser energy have been used for hair removal, from visible light to near-infrared radiation.  These lasers are characterized by their wavelength, measured in nanometers (nm):


  • Argon:  488 nm (Turquoise/Cyan) or 514.5 nm (Green) (no longer used for hair removal).

  • Ruby laser:  694.3 nm  (Deep Red) (only safe for patients with very pale skin).

  • Alexandrite:  755 nm (Near-Infrared) (safe and effective on all skin types, Fitzpatrick I-VI).

  • Pulsed diode array:  810 nm (Near-Infrared) (for pale to medium type skin).

  • Nd:YAG laser:  1064 nm (Near-Infrared) (made for treating darker skin types, though effective on all skin types).

  • IPL or Intense pulsed light:  810 nm  (Not a laser but used for hair removal) (for pale to medium type skin).


Pulse width (or duration) is one of the most important considerations.


The length of the heating pulse relates directly to the damage achieved in the follicle.  When attempting to destroy hair follicles the main target is the germ cells which live on the surface of the hair shaft. Light energy is absorbed by the melanin within the hair and heat is generated.  The heat then conducts out towards the germ cells.


As long as a sufficient temperature is maintained for the required time then these cells will be successfully destroyed. This is absolutely critical - attaining the require temperature is not sufficient unless it is kept at that temperature for the corresponding time. This is determined by the Arrhenius Rate Equation.


To achieve these conditions the laser/IPL system must be able to generate the required power output. The main reason why hair removal fails is simply because the equipment cannot generate the desired temperature for the correct time.  Spot size, or the width of the laser beam, directly affects the depth of penetration of the light energy due to scattering effects in the dermal layer. Larger beam diameters result in deeper deposition of energy and hence can induce higher temperatures in deeper follicles.


Hair removal lasers have a spot size about the size of a fingertip (3-18mm).


Fluence or energy density 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 heat up the follicles enough to disable them from producing hair.  Epidermal cooling has been determined to allow higher fluences and reduce pain and side effects, especially in darker skin.


Three types of cooling have been developed:


  • Contact cooling:  through a window cooled by circulating water or other internal coolant. This type of cooling is by far the most efficient method of keeping the epidermis protected since it provides a constant heat sink at the skin surface. The ALMA Laser makes use of this modern technology. Sapphire windows are much more conductive than quartz.

  • Cryogen spray:  sprayed directly onto the skin immediately before and/or after the laser pulse

  • Air cooling:  forced cold air at -34 degrees C


In essence, the important output parameter when treating hair (and other skin conditions) is power density - this is a combination of energy, spot diameter and pulse duration.


These three parameters determine what actually happens when the light energy is absorbed by the tissue chromophore be it melanin, haemoglobin or water, with the amount of tissue damaged being determined by the temperature/time combination.

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