Thinking of laser hair removal? Here’s what you need to know

How does laser treatment work?

Lasers emit a wavelength of light with a specific single colour. When targeted to the skin, the energy from the light is transferred to the skin and hair pigment melanin. This heats up and damages the surrounding tissue.

But to remove hair permanently and to minimise damage to the surrounding tissue, the laser needs to be targeted to specific cells. These are the hair follicle stem cells, which sit in part of the hair known as the hair bulge.

As the skin surface also contains melanin, which we want to avoid damaging, people are carefully shaved before treatment.

Will it remove hair permanently?

Laser treatment can either permanently reduce the density of the hair or permanently remove unwanted hair.

Permanent reduction in hair density means some hairs will regrow after a single course of therapy and patients will need ongoing laser treatment.

Permanent hair removal means none of the hairs in the treated area will regrow after a single course of therapy and no ongoing laser therapy is needed.

Whether hair is removed permanently or just reduced in density is influenced by:

• the colour and thickness of the hairs being treated

• the colour of the patient’s skin
• the type and quality of the laser used, and
• the competence and training of the person operating the laser.

However, if you have grey hairs, which have no melanin pigmentation, currently available lasers don’t work

How many treatments will I need?

The number of treatments you’ll need depends on your Fitzpatrick skin type. This classifies your skin by colour, its sun sensitivity and its likelihood to tan.

Pale or white skin, burns easily, rarely tans (Fitzpatrick types 1 and 2) People with dark hair can usually achieve permanent hair removal with 4-6 treatments every 4-6 weeks. People with fair hair will generally only achieve permanent hair reduction and after an initial course of treatment may need 6-12 treatments a month apart.

Light brown skin, sometimes burns, slowly tans to light brown (type 3) People with dark hair can usually achieve permanent hair removal with 6-10 treatments every 4-6 weeks. People with fair hair will generally only achieve permanent hair reduction and after an initial course of treatment may require 3-6 repeat treatments a month apart.

Moderate brown to dark brown skin, rarely burns, tans well or to moderate brown (type 4 and 5) People with dark hair can usually achieve permanent hair reduction with 6-10 treatments every 4-6 weeks. Maintenance will usually be required with 3-6 monthly repeat treatments. People with fair hair are unlikely to respond.

Re-treatments must be long enough apart to allow new hair growth to reach the level of the bulge.

Does the type of laser matter?

The type of laser not only influences how well it works, it influences your chance of side-effects.

Lasers suitable for hair removal include: long-pulse ruby lasers, long-pulse alexandrite lasers, long pulse diode lasers and long-pulse Nd:YAG lasers.

Intense pulsed light (IPL) devices are not laser devices but flash lamps that emits multiple wavebands of light simultaneously. They work in a similar way to lasers, albeit less effectively and they are much less likely to permanently remove hair.

To minimise the risk of damage to melanin producing cells on the skin surface, the choice of laser and how it’s used can be matched to your skin type.

Fair skinned people with dark hair can use an IPL device, an alexandrite laser or a diode laser; people with dark skin and dark hair can use a Nd:YAG or diode laser; and people with blond or red hair can use a diode laser.

To control the spread of heat and unwanted tissue damage, short laser pulses are used. The energy of the laser is also adjusted: it needs to be high enough to damage the bulge cells but not so high to cause discomfort or burns.