Summary: As one of the most consistently popular nonsurgical cosmetic treatments for both men and women, laser hair removal is performed for patients with many different skin tones and hair colors, not just the “ideal” combination of dark hair against lighter skin. For effective, lasting results in patients with darker skin tones, it’s essential that treatment take place with an experienced laser technician using the right approach.
Why Skin Tone Matters
The reason skin color impacts the efficacy and methodology of laser hair removal is due to the technology itself. Lasers use selective photothermolysis to target the hair follicle—not just the follicle itself, but the chromophore, or pigment-containing melanin within the hair follicle. This pigmentation absorbs the light energy, which is then converted to heat and dispersed throughout the hair shaft. The heat is intense enough to physically damage the follicle, thus limiting or preventing future regrowth.
This process is only effective during the anagen (active growth) phase of an individual hair; since hair has staggered growing cycles, repeated treatments are necessary. Proper timing of each treatment session is one of the primary factors that helps ensure the best laser hair removal results.
Patients with darker skin tones typically have darker hair as well, which should make them ideal candidates for effective laser hair removal. Yet, since the photothermolysis is selective, a higher contrast between skin and hair actually delivers better results. When the laser targets dark hair against light skin, all the energy is absorbed by the melanin in the hair follicle. In patients with both dark hair and dark skin, melanin in either the skin or the hair follicle may absorb the light energy. This leads to scattered, inconsistent results and carries the potential for more serious concerns such as hyperpigmentation or burning the skin.
The Best Strategy
There are three primary components to ensuring safe, successful laser hair reduction in patients with darker skin tones:
- Fluence: Since darker skin absorbs far more energy during treatment, particularly in response to constant exposure, using the lowest effectual fluence will minimize the potential for collateral tissue damage. Fluence should be further lowered in areas of higher density in order to avoid damage from excessive heat diffusion.
- Wavelength: The absorption properties of melanin are inversely proportional to the laser wavelength used. For example, epidermal melanin will absorb far more energy from a short-wavelength laser compared to one with a longer wavelength. As such, patients with darker skin tones should only be treated with a long-wavelength laser.
- Pulse: Longer pulse durations are best for darker skin tones, as this permits a more controllable, deliberate energy transference; the slower absorption into the epidermis reduces the potential for injury. Incorporating cooling mechanisms during treatment is essential to prevent thermal injuries in darker-skinned patients.
The laser hair removal technology in use today is extremely sensitive, and can just as easily penetrate epidermal melanin as it can follicular melanin. If the proper precautions are not taken, the cutaneous melanin will absorb the laser energy before it can reach the follicle, which can cause pigment and surface damage while leaving the hair itself unharmed. An experienced laser technician is able to choose the proper wavelength for safe, effective treatment while controlling the depth of penetration in order to compensate for higher melanin levels in the skin as well as ensure permanent hair reduction.