A Brief History of Laser Hair Removal Technology

Alison Sahoo
Palomar Medical Technologies, Inc.
December, 1997

The laser was invented in 1957 by American physicist Gordon Gould and developed into a working model three years later by Dr. Theordore Maiman. Since that time, it has become the cornerstone of a wide variety of medical and aesthetic applications, including long lasting removal of unwanted hair.

Laser energy, when applied directly to the human body, is absorbed by either the blood (hemoglobin), water (in the skin) or melanin (1), depending upon the color of the laser light used. Lasers generating colorless light (carbon dioxide and erbium lasers), blue-green light (argon laser), yellow light (pulsed dye and argon-pumped tunable due lasers), green light (copper vapor and krypton lasers) and red light (ruby, alexandrite and Nd:YAG lasers) were found early on to exhibit different properties and each be preferable for different medical procedures. Their highly precise beams were able to reduce bleeding during surgery; facilitate removal of diseased tissue, and reduce the need for anesthesia, enabling many procedures to be done on an outpatient basis. Additionally, healing time was often reduced, along with the sizes of post operative scars.

Early Investigation

Shortly after the laser’s introduction to medical applications in the early 1960’s, Dr. Leon Goldman began investigating the use of lasers to disable hair follicles. His goal was to develop a system which would treat many hairs at the same time - a bulk procedure which would treat large and/or densely-haired areas quickly. Although the concept was good, his system of directing laser energy at the melanin in the hair follicle resulted in damage to the surrounding skin (hyperpigmentation, hypopigmentation and/or blistering) when the free floating melanin in the epidermis also absorbed the ruby laser light. It would be nearly 30 years before the technology was developed which would control this unacceptable side effect.

Several companies, however, were inspired by these early efforts to use lasers for hair removal. In 1968, Union Carbide’s Korad division commissioned a study by Dermascan (manufacturer of the Proteus thermolysis machine) of the effects of applying laser energy directly to each hair follicle. They found that while this could be a viable modality to disable the growth process, a delivery mechanism (probe) could not be developed which would transmit sufficient laser energy but still be thin enough to be comfortable for the patient.

Nonetheless, in the early 1970’s, Omnicron Corp. launched a photo epilator which used coherent light (similar to, but less penetrating than today’s directed laser energy) to epilate hair. This was the first commercial attempt to disable hair follicles using the power of light, and did so by means of inserting a fiber optic probe into each hair follicle. As predicted by the Korad study, the system failed when it became obvious that sufficient light energy could not be comfortably introduced into each follicle with the probe.

This early attempt was followed by other companies who marketed systems that, like the Onmicron device, subjected individual hair follicles to directed light. In the early 1980’s, Lasetron, Inc. utilized an argon laser to direct energy at the hemoglobin surrounding individual hairs. This technology heated the hemoglobin and thereby coagulated the follicles. Although this device did prove effective indisabling the hair follicles, it was not faster (although it was considerably more expensive) than conventional electrolysis. It soon became apparent that this was not an economically viable procedure, and conventional electrolysis(2) remained the treatment of choice for long term/permanent hair removal.

Additional research into hair-by-hair epilation using light energy continued, and several technologies, including laser systems developed separately by Dr. Dennis Weisman at the University of Michigan, Paradigm Laser, Inc. of New York, and a directed light source similar to the Omnicron system (the "D’Plume" system manufactured by Carol Block, Inc.) have also been investigated. Although some of these have been patented and/or licensed for use, they have not yet been shown to offer any benefit over conventional electrolysis.

While these early systems involved application of laser light to individual hairs, the holy grail of hair removal has remained the bulk treatment of many follicles at once. This reduce the time required to treat an area by a factor of 50 or more and eliminate the need for repeated short-term treatments (waxing, shaving, depilatories). Both corporate and academic researchers continue to work on this problem, and several systems were investigated. Many of these technologies have since been commercialized (see "Current Technologies"). The first company to market a bulk treatment laser hair removal system became Thermolase, Inc. when it opened the first of a world wide chain of laser hair removal salons in La Jolla, California in January of 1996.

Current Technologies

The SoftLight system was developed in the early 1990s when Thermolase’s parent company, ThermoElectron, built and tested a low-power (for which skin cooling was not an issue) Nd:YAG laser for the removal of tattoos and birthmarks. In the process of treating body areas, it was noticed that, in certain cases, the hair fell out and did not readily return. The system was optimized by varying the
treatment parameters - notably by waxing the body area first and applying a black carbon gel which would absorb the laser energy and more completely disable the follicles.

During this time, some two dozen specialized laser companies that had been actively researching medical applications, began to introduce systems that would treat a variety of medical and aesthetic conditions. Many of these systems represented the results of extensive research - on average 5 - 7 years of hardware development and 3 - 5 years of clinical testing. The new laser procedures quickly found acceptance by both physicians and patients, with more than 400,000 PRK procedures for nearsightedness performed worldwide since the treatment’s introduction in 1988 and over 200,000 skin resurfacing procedures performed since inception in 1994. The total estimated 1996 laser system sales of $1.28 billion meant approximately 9,700 new installed systems worldwide. The body of research on laser-tissue interactions that has resulted from these ophthalmic (nearsightedness, farsightedness, glaucoma, macular degeneration, etc.), gynecological (hysterectomies, breast reduction, etc.) dental (lesion removal, crown lengthening, bridge impressions, gum reshaping, whitening, hole drilling, etc.) surgical and aesthetic (skin resurfacing, removal of wrinkles, tattoos, spider veins, lesions, warts, stretch marks, scars, etc.) systems has also been used to further the development of systems specifically designed for hair removal.

In 1994, Dr. R. Rox Anderson and Dr. Melanin Grossman of the Massachusetts General Hospital Wellman Laboratories of Photomedicine, working with the Goldman model of a high-power ruby laser directing energy to the melanin in the follicle, hit upon the idea of using a water-cooled delivery handpiece to cool the skin surface when the laser energy was applied to many follicles. This proved to be the key in making the melanin-model viable. Over the next 2 years, the key operating parameters of spot size, fluence (energy density), pulse duration and repetition rate were optimized so that the maximum amount of energy could safety be delivered to the largest skin area with each pulse and create a heating effect in the follicle ("photothermolysis") that would prevent regrowth. This process of photothermolysis - coagulating the follicle using light energy - is analogous to the electrolysis modality of thermolysis, in which a heating effect is created in the follicle using short-wave energy. This maximizes the damage to the hair follicles, for a treatment that offers clients freedom from unwanted hair for several times as long as the nearest non-permanent alternative.

Since the commercialization of the Anderson-Grossman technology (marketed by Palomar Medical Technologies, Inc. as the EpiLaser), 5 other laser hair removal systems have been cleared to market by the US FDA that incorporate skin-cooling technologies and offer bulk hair removal via photothermolysis. Several of these use proprietary cooling gels, which, when applied to the skin during laser treatment absorb excess energy and prevent skin from damage. Others deliver laser energy of a longer pulse duration that theoretically is absorbed more completely by the target follicles ("thermokinetic selectivity") with less heat absorption in the skin. With the exception of the SoftLight Nd:YAG, all of these systems target laser energy to the melanin in the follicle to create a heating effect and prevent regrowth.

It should also be noted that of the 9 laser or photo-based systems currently cleared to market by the US FDA for bulk hair removal, 2 of these are non-laser light sources. These technologies deliver coherent, columnated light of many wavelengths (colors) which the system operator filters to select the wavelength best suited for absorption by melanin in the follicle.

What does the future hold? With more than 600 US facilities now offering laser hair removal, this treatment appears to meet a strong consumer demand for quick, long lasting hair removal. In Europe and Australia, where the treatment has been offered since 1995, public enthusiasm remains strong. Research continues to optimize both results (provide the longest lasting, most consistent results with minimal adverse side effects) and equipment (boost system reliability, ruggedness and ease of use). Practitioners are also developing new ways to integrate laser with electrolysis for both quick and permanent results, and improving pre & post treatment protocols to minimize side effects and maximize results.

Notes

  1. These are the only naturally occurring substances in the human body that will absorb laser energy. Tattoo ink can also act as a chromophore, and is effectively removed using the Q-switched ruby laser.
  2. Electrolysis here refers to the 3 needle-based modalities (galvanic, thermolysis, blend). It should be noted that in the 19 US states with no electrology licensing laws, the term "electrolysis" may also be used for the non-needle (aka "tweezer") modalities which claim permanent hair removal by touching target hairs with an electrified probe. These systems are dependent upon the hair conducting this current into the base of the follicle to create a heating effect and prevent regrowth. There is much current controversy in allied health circles as to the effectiveness of these technologies vis-à-vis needle electrolysis.