Pulsed light hair removal: how does it work?

Pulsed light hair removal is a technique that utilises a device emitting light rays to eliminate hair. This method is based on the process of photothermolysis which aims to produce thermal damage in the targeted element, in this case hair, while minimising damage to the surrounding tissues.

For this, the laser hair removal device will emit light pulses that will be captured by melanin, a pigment present in hairs and responsible for their colour. This acts as a chromophore, that is, a chemical compound that absorbs light at a specific wavelength.

As soon as melanin has absorbed light, it will transfer this energy to the surrounding molecules, causing a rise in temperature. This heat will be transmitted to the hair bulb, which will cause significant damage, particularly the apoptosis of the hair follicle.

Hairs grow independently and are not all at the same stage of the hair growth cycle. Therefore,several sessions of pulsed light hair removal are necessary to achieve lasting results. This methodallows to eliminate nearly 80% of hairs from the legs and underarms. Being minimally painful, it is also suitable for the sensitive bikini and facial areas.

It should be noted that hair removal using Intense Pulsed Light (IPL) has no effect on light or bleached hair,as these have a low melanin content, which does not allow them to be accurately targeted by IPL. It is primarily used on dark hair, which is rich in melanin. Moreover, it is not highly recommended for tanned skin, due to the similar colour of the skin and hair.

In addition to being performed in a salon, it is possible to carry out IPL (Intense Pulsed Light) hair removal at home by purchasing an IPL device. However, several spread-out sessions are necessary to achieve a lasting result. It is recommended to perform between 6 to 8 sessions on average, each spaced a month apart. The results are generally visible after the third session. Moreover, sun exposure is advised against after each session, as the skin is sensitive and more susceptible to burns and sunburn. This is why IPL hair removal is commonly scheduled in winter.

Hair removal using pulsed light requires several steps.

• An initial consultation whose aim is to determine the feasibility of the procedure, knowing that it presents some risks ;

• Theestablishment of a quote which varies depending on the area to be treated and the number of sessions to be scheduled;

• The physical preparation, by shaving the hair two days before the session so as to act at the time of regrowth and better target the roots;

• Theapplication of a conductive gel which is applied to the area to be treated. It helps to cool the skin and promote the circulation of light towards the hair follicles. This comes from the ability to minimise the reflection of pulsed light, allowing it to be better directed towards the hair follicles.

• The session itself involves the mandatory use of protective glasses to shield you from light rays. Pulsed light is incompatible with moles and tattoos, so it is necessary to protect them. In a professional setting, the application of a numbing cream can help prevent any potential discomfort (tingling, warming of the area to be treated, etc.). To remove hair, simply glide the device over the skin, targeting all areas.

• DIERICKX C. C. Hair removal by lasers and intense pulsed light sources. Dermatologic Clinics (2002).

• HAEDERSDAL M. & al. Laser and intense pulsed light hair removal technologies: from professional to home use. British Journal of Dermatology (2011).