Science of 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 generally accepted in the dermatology community and laser hair removal is widely practiced in medical clinics around the world.

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.

Lasers can cause localized damage by selectively heating dark target matter, melanin, in the area that causes hair growth, the follicle, 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.  Laser works best with dark coarse hair.

Light skin and dark hair are an ideal combination, being most effective and producing the best results, but new high powered lasers are now able to target black hair in patients with dark skin.

Laser hair removal has become popular because of its speed and efficacy, although the efficacy is dependent upon the skill and experience of the laser operator and the choice and of different laser or light technologies used for the procedure.

A medical clinic needs to be evaluated on whether Laser, Light and Light/Heat treatments are available to cater for patients with different skin types and hair conditions. Cutis Medical Laser Clinics has the full range of 1064nm Laser, IPL (Limelight) and Light/Head (LHE Radiancy) equipment.

Comparison of different treatment options

A 2006 review article in the journal “Lasers in Medical Science” compared IPL and both alexandrite and diode lasers. The review found no statistical difference in effectiveness, but a higher incidence of side effects with diode laser based treatment.

Hair reduction after 6 months was reported as 68.75% for alexandrite lasers, 71.71% for diode lasers, and 66.96% for IPL. Side effects were reported as 9.5% for alexandrite lasers, 28.9% for diode lasers, and 15.3% for IPL.

Intense pulsed light (IPL) epilators, though technically not containing a laser, use xenon flash lamps that emit full spectrumlight. IPL-based methods, sometimes called “AFT”, “phototricholysis” or “photoepilation”, are now commonly (but incorrectly) referred to as “laser hair removal”.

IPL systems typically output wavelengths between 400 nm and 1200 nm. Filters are applied to block lower wavelengths, thereby only utilising the longer, redder wavelengths for clinical applications.

Regulation

In Singapore, only physicians can perform laser hair removal while IPL treatments can be performed by trained aestheticians as well.

How many sessions are needed?

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 Dr. Sylvia Ramirez of Cutis Medical Laser Clinics 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 these types of patients, Dr. Sylvia Ramirez of Cutis Medical Laser Clinics uses the LHE Radiancy treatment which combines Light and Heat.

For darker skin patients with black hair, the long-pulsed Nd:YAG 1064nm laser with a cooling tip can be safe and effective when used by an experienced practitioner such as Dr. Sylvia.

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 a session can be more painful as well as counteract the effects of the treatment.

Side effects and risk

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. Numbing creams are available at Cutis Medical Laser Clinics to minimize pain sensations for patients.

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.