When selecting lasers for laser hair removal, which parameter is critical for patient safety and efficacy?

When selecting lasers for laser hair removal, the wavelength is a critical parameter for both patient safety and the efficacy of the treatment. The wavelength of the laser determines the absorption characteristics of the hair follicles and the surrounding skin. Different wavelengths penetrate the skin to varying depths and are absorbed by the pigment in the hair and skin differently.

For effective hair removal, a wavelength that is selectively absorbed by the melanin in the hair follicle is ideal. This ensures that the energy from the laser can effectively target and damage the hair follicle while minimizing the heat damage to the surrounding skin. For example, longer wavelengths, such as those found in the Nd:YAG laser, can penetrate deeper into the skin and are suitable for treating darker skin types, as they have a lower absorption rate in melanin in the skin.

Although factors like pulsed duration, cooling effects, and the cost of the device are significant in the context of comfort and efficiency, they are secondary to the fundamental requirement that the wavelength must be appropriate for the specific hair type and skin color of the patient. This directly affects the success of the procedure and the safety profile, making wavelength the most critical parameter to be considered in laser hair removal.