Why the margin for error is narrower

Laser hair removal works by selective photothermolysis: light is absorbed by melanin in the hair follicle, which heats and damages the follicle while sparing the surrounding skin.

In darker skin, there's also a lot of melanin in the epidermis, directly in the beam's path. Some of the energy meant for the follicle is absorbed at the surface instead. The physics are the same, but the window between an effective dose and an unsafe one is narrower.

Wavelength comes first

Melanin absorbs light less as the wavelength gets longer. 1064 nm (Nd:YAG) is the least absorbed by surface melanin, which is why reviews and clinical studies support long-pulsed 1064 nm as the first choice for types V and VI. Type IV is more of a judgement call, based on hair, area and history.

One important point: the same wavelength on a different device does not mean the same settings. Pulse durations, spot sizes and cooling vary between machines, so never copy a setting quoted for a different device. Work within your own manufacturer's parameters.

The other levers you control

  • Pulse duration. Longer pulses let the epidermis shed heat while heat builds in the larger follicle.
  • Fluence. Start lower than you think you need and increase between sessions, not within one. But aim for a real endpoint: under-treating isn't risk-free either.
  • Cooling. In darker skin, cooling is part of your safety margin, not just comfort. Check it's working before the first pulse.
  • Spot size and technique. A larger spot delivers more energy at depth. Don't overlap or stack passes, and make sure the shave is close.

Before you treat

Most of the safety in this treatment happens before the handpiece comes out. Agree a realistic course length, name the specific risks (pigment change, blistering and paradoxical hair growth) out loud and on the consent form, and make sun protection part of the plan.

Take a pigment and scarring history, photograph the area before session one, and patch test on the area you'll treat, at the settings you'll use. Inspect the site yourself after the full interval your protocol requires.

Reading the endpoint on darker skin

The endpoint you want is mild redness and slight swelling around the follicles. On darker skin, redness is harder to see, so feel the skin for heat and swelling and ask the client how the sensation compares with earlier passes. Stop immediately if you see greying, whitening or blistering.

When something goes wrong

Post-inflammatory hyperpigmentation is the most common adverse outcome in this group. Stop treating the area, photograph and document it, advise strict sun protection, and refer to a GP or dermatologist if it's worsening or distressing the client.

Learn it properly: Skin Types IV to VI Safely

Skin Types IV to VI Safely is a 15-minute online masterclass for laser technicians and for clinics training their teams. It covers the physics, each setting you control, consultation, patch testing, the first treatment, reading the endpoint and managing complications.

  • 15-minute video masterclass
  • Short quiz at the end
  • Certificate of completion for every learner who passes
  • £25
View the course

Frequently asked questions

Is this a qualification?

No. It's a knowledge course with a certificate of completion. It's designed to strengthen what you already know, not to replace a formal laser qualification.

Can clinics use it to train staff?

Yes. Each team member enrols separately and gets their own certificate.

Is it only for 1064 nm machines?

No. The principles apply to any machine. The course explains why, and why you should always work within your own device's parameters.