The removal of hair is considered a cosmetic procedure, since it achieves results that are considered appealing by modern standards of beauty. The practice of removing hair is not new, as even the Ancient Egyptians did it. However, they did it to avoid lice, fleas, and other parasites, whereas hair removal is today considered a cosmetic procedure. The relatively recent popularity of removing hair from the body for women is a result of the pervading concepts of gender differentiation. Others remove hair as social statements, religious practices, acts in defiance to societal norms, or for reasons of comfort.

There are two general classifications of approaches, differentiated by the parts that they remove. One is called epilation, while the other is named depilation. While depilation removes hair from the surface of the skin upward, it does not remove the structures below the surface as in epilation. Depilation is performed most commonly be shaving the hair with sharp implements, or disintegrating the hairs using chemicals that weaken and break the disulfide bonds that make hair strong.

Epilation removes even the roots of hairs, so the area stays hairless longer. The hairs are either pulled out or burned at the follicle level. The hair-producing structures are temporarily knocked out of commission, which contributes to the longevity of effect. Hair is pulled out with the help of tweezers, waxes, thick solidifying pastes, or cotton threads, depending on the procedure. The hairs are burned using either electrical pulses or pulses of concentrated light. Intense Pulsed Light generators are used for the latter.

As mentioned, those with light-colored hair cannot have their hair removed this way. Another problem arises when the patient has dark skin. The dark skin absorbs more light, and can thus be irritated or burned in much the same way as the hair. Fine hairs can also be more difficult to remove, as their size reduces the profile for light absorption. There are different lasers for use with dark-skinned patients. This procedure also cannot remove very fine hairs. Acne may flare up after laser hair removal. The presence of swelling, pale spots, scab forming, and purpura are also possible.

Intense Pulsed Light generators are devices that use high-power xenon flash lamps to create short bursts of strong light. Flash lamps use a variety of gases as their flash medium, and the use of xenon produces a purplish light. The light produced is full-spectrum light, which means it includes light from outside the visible portion of the electromagnetic spectrum. These lamps are attached to electrical assemblies with a capacitor that builds up high charges of electricity and releases them very quickly. This is key to achieving the current required for the gas inside the lamp to ionize and emit photons.

The light produced by the quick, intense flash is focused using mirrors and lenses, which is then directed to the focal point outside the device. The focal point is where the light is strongest, and thus is where the most heat is generated. This focus is where the area of application is centered. When a pulse is fired, the light penetrates a short way into the skin. The hairs have the highest concentration of pigmentation from melanin, which means they absorb more light that is converted to heat energy. The hair all the way from the follicle is vaporized in an instant, while the skin is not burnt. The hair can also be darkened with chromophores, to make the heat generation more efficient. Because red and blond hairs are not removable with this method as they cannot absorb enough light, they are dyed to brown or black.

Repeated flashes distributed over the area of depilation are then performed to complete the procedure. The device may be a small handheld device wired to a power source or mounted on an articulated mechanical arm. These devices are rather expensive and consume large amount of electrical power, contributing to the price of these procedures.

Intense Pulsed Light generators are technically not lasers. The discrepancy lies in the coherence of the light and wavelengths produced. Nonetheless, the name laser has become attached to it under popular usage, and thus any hair removal operation performed with a source of strong light for burning away hair is called “laser hair removal”.