Laser hair removal (LHR) uses concentrated light to target and disable the hair follicle. The concept began shortly after the invention of the first laser in 1960, but the safe and commercially viable procedure only emerged in the mid-1990s after decades of scientific refinement. The first effective systems received United States Food and Drug Administration (FDA) clearance for permanent hair reduction around 1997.
The Experimental Dawn (1960s-1970s)
The story of laser hair removal begins with the invention of the first working laser by physicist Theodore Maiman in 1960, which used a synthetic ruby crystal. Researchers quickly explored the medical applications of this new technology, including its potential for hair removal. Early attempts involved using these initial lasers, such as the ruby laser, to target hair follicles.
These initial experiments were largely unsuccessful because the technology lacked precision and control. The continuous wave lasers of the 1960s and 1970s were slow and often caused significant damage to the surrounding skin tissue. The energy was not delivered effectively enough to destroy the hair follicle without causing severe burns.
A YAG laser was approved by the FDA for hair reduction as early as 1964, though it did not provide permanent results. Later in the 1970s, a different laser technology used a fiber-optic probe to target individual hairs. This method was painful and ineffective, leading to its eventual removal from the market by the FDA.
The Scientific Breakthrough (1980s-1990s)
The fundamental scientific concept that made modern laser hair removal possible was developed in the 1980s by Dr. R. Rox Anderson and Dr. John Parrish. They introduced the theory of Selective Photothermolysis (SPT) in 1983, which provided the blueprint for safe and effective laser treatments. SPT established that a specific target tissue, or chromophore, could be destroyed by matching the laser’s wavelength and pulse duration to the target’s absorption characteristics and thermal relaxation time.
In the context of hair removal, the target chromophore is the melanin pigment found in the hair shaft and follicle. By using a wavelength of light highly absorbed by melanin and a pulse duration shorter than the time it takes for the surrounding skin to cool, the follicle could be heated and damaged while minimizing harm to the epidermis. This breakthrough shifted the procedure from a damaging experiment to a controlled medical treatment.
The mid-1990s saw the introduction of the first commercial lasers based on the SPT principle, including the Alexandrite and Diode lasers. These devices specifically targeted melanin, making them highly effective for individuals with light skin and dark hair. The first FDA clearance for permanent hair reduction was granted around 1997, marking the transition to a reliable cosmetic procedure. The development of the Fitzpatrick Scale in 1988, which classifies human skin color, also played a significant role by providing a standardized method for practitioners to select safe treatment parameters.
Modern Era and Accessibility (2000s-Present)
The early effective lasers were primarily limited to treating lighter skin tones because the melanin in darker skin would absorb too much energy, leading to burns and pigmentation changes. A major advancement in the 2000s was the widespread adoption of the Nd:YAG laser, which operates at a longer wavelength of 1064 nanometers. This longer wavelength penetrates deeper, allowing it to bypass the melanin in the epidermis and safely target the hair follicle in individuals with darker skin tones (Fitzpatrick types IV-VI).
Technological improvements also focused on enhancing patient comfort and treatment speed. Modern laser systems incorporate advanced cooling mechanisms, such as contact cooling and air cooling, which protect the outer layer of the skin during the high-energy pulse. The introduction of “in-motion” technology, where the laser head is continuously moved across the skin, significantly reduced treatment times for large areas.
Accessibility expanded further with the development of at-home devices, which began to appear in the late 2000s. While generally less powerful than professional-grade equipment, some consumer devices, such as the TRIA laser, received FDA clearance for permanent hair reduction, making the technology more affordable and widely available. Today, the procedure is faster, safer, and effective for nearly all skin types, though light-colored hair, such as gray or blonde, remains challenging due to the lack of melanin chromophore.