Laser hair removal is a non-surgical, cosmetic, permanent hair reduction treatment that is rapidly growing in popularity. As the name suggests, the treatment involves using a laser to remove hair from any part of the body – with the exception of the areas around the eyes, eyebrows and the eyelids. The areas that are usually treated include the back, chest, buttocks, stomach, bikini-line, legs, neck, face, and underarms. As well as removing unwanted body hair, these lasers are also very effective at treating ingrown hairs, which usually only require one session (although this does depend on the size of the area to be treated). Laser hair removal results in the permanent reduction of the total number of hairs in an area, but not permanent hair removal. Usually, laser hair removal permanently removes 70% – 90% of actively growing hair, depending on the patient. The definition of permanent hair reduction, according to the FDA, is “the long-term, stable reduction in the number of hairs re-growing after a treatment regime”. Therefore, patients may find that hair in the treated areas has regrown a few years after their last treatment.
Laser hair removal makes use of a specially-designed laser, which produces a high-energy beam of a single color of light. Not every laser emits the same color light and different colors have different wavelengths, which determines the depth of penetration. Some lasers emit a short wavelength that just burns the hair, only providing a temporary solution. Other, more effective, lasers produce a longer wavelength of light that penetrates deeper into the skin, targeting the root of the hair.
Intense pulse light machines are often incorrectly called lasers, but, unlike lasers, these devices are not able to target specific areas. This targeting of specific areas is known as selective photo-thermolysis. Intensive pulse light machines tend to be cheaper than laser devices, and many clinics choose to use them for this reason. However, actual lasers are more effective than these intensive pulse light devices. The three main types of hair removal lasers are alexandrite lasers, diode lasers, and YAG lasers. The type of laser used for treatment is determined by the skin type of the patient, with alexandrite lasers being used on light skin tones and YAG lasers being used on dark skin tones.
Diode lasers are used on all skin tones.
Hair removal lasers focus on a clump of hair follicles under the skin – unlike electrolysis or tweezing, which focuses on a single follicle. These lasers produce intense light energy that is absorbed by the dark melanin pigment found in hair. The melanin pigment converts the light energy into heat energy, which travels down the hair’s shaft to the root of the follicle. Dark hair colors, such as black and dark brown, contain eumelanin, while lighter shades such as blonde and red hair contain pheomelanin.
Eumelanin absorbs more energy than pheomelanin, and consequently, laser hair removal treatments are more effective in patients with darker hair colors. There are no melanin pigments present in grey and white hair to absorb the light produced by hair removal lasers, and as such, this method is ineffective on these shades of hair color. However, melanin is not only located in hair but is also found in the skin. Furthermore, the darker a person’s skin is, the more melanin there is to absorb the light energy and convert it to heat, making it harder to avoid damaging the surface of the skin. As such, the laser has to be focused on the target area long enough to heat the hair, but not so
long that it heats up and damages the skin.
The heat from the laser damages the hair follicle and produces inflammation. This inflammation sends a signal to the hair follicle, causing it to go into its resting phase (Known as the Telogen phase) and hindering its ability to grow. Hair growth is not uniform across the body or within specific areas and hair is not actively growing all the time. Hair growth is a cyclic process moving between three phases: the anagen (growing/active) phase; the catagen (intermediate) phase; and the telogen (resting/shedding) phase. Hair removal lasers target hairs in the first phase of the growth cycle – the growing or anagen phase – as this is the only phase where melanin is produced. Hair follicles in the growth phase contain the most melanin (are the darkest) and therefore absorb the most energy.
Before the procedure, the patient is given a pair of goggles to protect their eyes. Often, a topical anesthetic will be applied to the area to be treated to reduce discomfort. During the procedure, the laser device is held against the skin and activated. With certain lasers, this will also include epidural cooling methods, such as contact or air cooling.
In the hours following laser hair removal treatment, redness and swelling may occur, while hair will begin to be shed and fall out after 2 – 3 weeks. However, as hair growth is not uniform, a number of sessions are required to treat each batch of hair as it enters the active phase of growth. With the exception of the scalp, actively growing hairs in the anagen phase account for 20 – 40% of the total hair of a particular area of the body. As such, multiple treatment sessions are needed. These sessions are spaced accordingly to allow for hair to cycle into active growing phases so that treatment is successful. The number of sessions a patient needs is determined by factors such as hair color, skin pigmentation, hair texture, hair density, hormonal status (hormonal changes can trigger hair regrowth), and if the patient is on medication (some medicines can affect hair growth).
Fine hair cannot absorb as much heat as coarse hair, so treatment is less effective and requires more sessions.
Darker hair has more melanin to absorb energy, so treatment is more effective and requires fewer sessions. Dark skin has more melanin, so hair removal lasers cannot be focussed on an area for as long as they can with lighter skin, for fear of causing damage. This may necessitate more sessions.
The number of laser hair removal sessions is also determined by the areas being treated. Treating facial hair will require more frequent sessions than treatments to other parts of the body, as the length of the hair growth cycles is much shorter than that of other areas. Typically, facial treatments are spaced about 5 weeks apart, while leg and back treatments are spaced 8 – 10 weeks apart. During the course of treatment, hair in the targeted area becomes less dense after each subsequent session. On completion of the treatment, patients find that up to 70 – 90% has been permanently removed, while the hair that returns is softer and lighter. To maintain treated areas and keep them completely hairless, further sessions will always be required. However, after a number of courses of Laser hair removal, these additional treatments only be needed once a year, or even less frequently. The frequency of follow-up treatments depends entirely on the patient and the area being treated. The number and frequency of treatments can make comprehensive laser hair removal costly and this has led to an increase in home laser devices on the market. Home laser hair removal is cheaper than a complete hair removal treatment course from a professional and affords the patient more privacy. However, home laser hair removal is not without its own drawbacks. For example, most devices on the market are smaller than the professional lasers and as such, target smaller areas of the skin. This will mean that more time and sessions will be needed to achieve successful total hair removal.
Laser hair removal is fast becoming one of the most popular hair removal treatments for both men and women around the world. Reasons for the increase is in popularity include how quick and convenient laser hair removal is, as well as the lower level of pain experienced by patients when compared to other hair removal methods. Lasers can treat much larger sections of skin than waxing, tweezing, and electrolysis with less discomfort to the patient. In fact, studies have shown that laser hair removal was approximately 60 times faster, less painful and more reliable than the electrolysis methods tested (although there have been recent improvements in electrolysis techniques). That being said, laser hair removal is not, however, completely pain or discomfort free.
The discomfort associated with laser hair removal varies and is described as a “snapping sensation” – similar to the feeling of an elastic band snapping against the skin – coupled with the heat generated by the laser. The level of discomfort experienced is dependent on the individual's skin type, the laser being used, the area of the body being treated, hair density, hair thickness, as well as the level of their pain threshold. The most discomfort is usually experienced is during the first session, as this is when the hair density is at its peak. Additionally, certain areas of the body are more sensitive than others, and it is recommended that individuals with sensitive skin, or who have a low pain threshold, to apply a topical anesthetic is prior to treatment. This will reduce any sensations of pain or discomfort. The most sensitive areas that undergo laser hair removal include the upper lip, underarms, genitals, and bikini line.