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Laser Hair Removal Works, Part 1 – Selective PhotothermolysisLaser hair removal, like all other laser dermatology, functions because of the principle of Selective Photothermolysis. This concept, first discovered and documented by Drs. Parrish and Anderson in 1983[1], outlines the way in which light can pass harmlessly through the body’s live tissues and selectively bring about changes at the site of light absorption. In layman’s terms this means that laser light can be designed to specifically target certain things in our body to bring about a certain result. With laser hair removal, lasers are designed to specifically target the melanin within a hair follicle, creating localized heat in the follicle and stimulating inflammation which triggers a prolonged resting or telogen phase for the hair follicle. Thus the hair falls out and is replaced by an invisible telogen hair for a prolonged period of time. The end result: no hair in the treated area.How Laser Hair Removal Works, Part 2 – Chromophore TargetingAnyone who has ever walked on black pavement on a hot day knows that light is absorbed by dark colors. Darker materials absorb more light. This is critical in laser hair removal as most of the hair in our skin contains melanin pigment (grey or white hair is the exception), a naturally occurring pigment which gives our skin and hair its color. By selectively targeting the melanin in the hair shaft, we can cause controlled damage to the hair follicle without injuring the surrounding skin.[2][3][4] Lasers now in use have become highly precise at targeting the melanin within the hair shaft.How Laser Hair Removal Works, Part 3 – Triggering the Telogen Phase  Number of Treatments NeededThe number of laser hair removal sessions needed can vary from one patient to another, however generally it may require at least three to four initial treatments administered at 6-8 week intervals to achieve hair removal in a given area. This is because not all hair follicles will be treated in the first sessions. Following this initial series of treatments, maintenance treatments are required at longer and longer intervals. It may be 3-4 months, then 6 months and perhaps even years between treatments. Hair in a treated area will be thinner in diameter and less dense after a series of treatments for a very long time-but to keep all the hair away in a given area-maintenance treatments are always required.Areas of the Body TreatedI have almost treated every area of the body which can grow hair. Often athletes such as swimmers or professional actors or models may treat most of their bodies as the excess hair may be an impediment in their careers. I do not use lasers to treat hair between the eyes, or monobrow. For this I recommend electrolysis or waxing. Certain areas of the body can be easier to treat than others. For example, the lip and chin are fairly easy areas to treat with laser hair removal. Other areas, for instance the back of the neck, have not responded as well in my experience. I have also seen a phenomenon known as Paradoxical Hair Growth, which is a rare side effect of laser hair removal particularly in patients of Mediterranean decent. This occurs when treating along the jaw line of a patient we see hair growth in the area adjacent to or at the treatment area. This can be removed with further laser treatment utilizing cooling around the treatment area. Lasers Used for Laser Hair RemovalThe original laser used for laser hair removal, the Ruby 694 nanometer laser, has since been abandoned for hair removal as it often resulted in unwanted complications. Today there are three main types of lasers used for hair removal:
Darker Skin and Laser Hair Removal Treating darker skin can be a serious challenge for a laser surgeon, particularly if you are inexperienced. This is true not only for laser hair removal, but for any treatment. The melanin, which is giving the skin its color, is designed to absorb light. This is paradoxical as we are targeting below the skin’s surface, however the melanin is stealing away that light and creating the potential for injury to the epidermis in the process. In order to avoid damaging the epidermis the surgeon performing the treatment must choose the laser and the energy levels very carefully. Contact and spray cooling can be used to prevent epidermal damage from the laser. When treating African American patients or patients with skin type 4 and above we often will use the longest wavelength lasers. This is because melanin in the skin is designed to absorb shorter wavelengths of light, and we can therefore bypass the melanin in the skin.Contraindications for Laser Hair RemovalPatients who have the following may not be good candidates for laser hair removal:
Efficacy and Hair ReductionLaser hair removal was approved by the FDA in 1996[5] and since that time many millions of procedures have been performed. Patients who are good candidates for the procedure generally see a reduction in the number of hairs and the thickness of hair anywhere from 80% to 90% following a complete series of treatments. Recent evidence-based reviews of the literature have concluded that hair removal with lasers is more efficacious than alternatives and side effects are rare with the latest laser systems[6] Between treatments you may see hair regrowth as the hair follicles which were not treated in the previous session continue to cycle. These hairs will be treated during subsequent sessions of hair removal until all follicles are subjected to treatment.Maintenance sessions may also be required annually to maintain the total reduction of the hair in the treatment area. Pain during TreatmentThe energy absorbed into the hair follicles produces heat, which patients will feel. This may produce mild to moderate pain. Numbing creams can be applied to dull the pain, however I choose to have this done in my office rather than allow the patient to self-administer. Pain can certainly vary between patients, and some patients may notice less pain than others. Some factors which may influence the amount of pain felt are:
The clinician can adjust the laser to reduce the amount of pain a patient is feeling. CoolingWhen we are performing laser hair removal we are aiming at a target beneath the surface of the skin. Since melanin pigment absorbs laser light, and melanin pigment resides on the skin’s surface, melanin will naturally absorb the laser light as it passes through to the hair shaft. As it absorbs the light it can heat the skin and cause injury. To diminish the pain, prevent injury, and increase treatment efficacy we may cool the surface of the skin using:· Contact Cooling: This method may use a variety of techniques to cool the surface skin. Some include a chilled metal or glass plate, or two glass plates with cool water running between them. · Dynamic Cooling Device: Developed by J Stuart Nelson[7] and his colleagues, the dynamic cooling device sprays cryogen on the skin between laser pulses to reduce the pain associated with laser treatment. Pneumatic Skin Flattening to Reduce PainIn addition to cooling, a new technology may also be used to reduce the pain associated with laser treatment, pneumatic skin flattening (PSF). PSF works by creating a vacuum through a chamber which pushes blood out of the treatment area blocking pain signals to the brain. Known as the Gate Theory[8], the process relies on the afferent inhibition of pain transmission to the vertebral column. Translated to English that means pain from the laser light is blocked by the vacuum sensation, the nerves having first felt the suction sensation rather than the heat[9]. Risks and Side EffectsThe risk of side effects from laser hair removal is generally quite low in appropriate candidates. Risks may include hypopigmentation (whitening of the skin), erythema, epidermal damage, and paradoxical hair growth. CostCost can vary dramatically from $200 per session for a small area to a $1000 or more for a larger area. The market you live may influence the cost as well. It’s important to go to a laser center where the provider is experienced and know what they are doing. There really are no bargains in laser surgery.
Laser hair removal is most effective on short, visible hairs. Several days prior to the treatment you may be asked to shave the area to be treated and allow some stubble to grow. It’s advisable not to wax or pluck the hair prior to treatment. Treatment may last anywhere from several minutes to an  |
Vivek Khandelwal
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I mean something that would practically replace Razor forever cause its is so very mechanical.?