Laser, pulsed light...Is permanent hair removal effective and safe?

Three long-term hair removal techniques are authorized in France. What do they consist of?

three methods of permanent hair removal are authorized. How do they act? Are they effective in the long term and above all, without risk? Le Figaro takes stock.

To fully understand how these techniques work, you must first look at the anatomy of the hair. The latter is born in the hair follicle, a sort of small pocket sunk a few millimeters under the skin. At its base is the root, from which it forms. There are also melanocytes, cells secreting a brown pigment, melanin. It is this pigment that is targeted by two permanent hair removal techniques: laser and pulsed light. This involves sending a beam of light to the hairs: the melanin absorbs this light and transforms it into heat, which has the effect of destroying the root of the hairs.

Pulsed light machines are of variable power: some are content to weaken the hair while others are capable of destroying it.

The difference between laser hair removal and pulsed light hair removal is the energy level of the light beams bombarded on the hairs. The laser uses a powerful one-wavelength beam that specifically destroys the hair root. The pulsed lamp emits several wavelengths of lower energy. Pulsed light machines are therefore of variable power: some are content to weaken the hair while others are capable of destroying it.

6 to 8 sessions

Both of these techniques only work on hair in the growth phase, which is about 20% of body hair at any given time. Between 6 and 8 sessions of 20 to 60 minutes, each is therefore often necessary to overcome all the hair capital. Laser hair removal can only be performed by dermatologist doctors, which is the source of discord with aestheticians.

On the other hand, beauty centers have the right to use pulsed light lamps. “They are less powerful than those used in medical centers, they require even more sessions”, specifies Dr. Isabelle Gallay, dermatologist, and vice-president of the National Syndicate of Dermatologists Venlogists (SNDV). And above all, they are much less powerful than lasers.

A third technique exists, but it is much less used because it is necessary to proceed hair by hair: it is electrolysis. A needle is inserted into the root, then sends an electric shock to destroy it. The shorter sessions must be repeated more frequently. Like the other two techniques, electrolysis can only be performed by doctors.

What efficiency?

Regardless of the technique chosen, "once the sessions are over, no hair grows back in the majority of cases", emphasizes Dr. Gallay. However, in certain hormone-dependent areas (lips, chin, lower abdomen, or chest), a greater number of sessions may be necessary.

However, some hairs may grow back a few years later, especially in these areas. Indeed, it happens that some cells escape destruction and can re-grow hair afterward. This is why dermatologists prefer to talk about long-lasting hair removal, not permanent hair removal.

Note that these techniques are not all effective on all skin types. Ideal candidates for pulsed light and the most common lasers are people with fair skin and dark hair. On dull skin, these two techniques can cause burns by reacting with the melanin present in large quantities in the skin.

Conversely, it is more difficult to treat light, blond or red hair, because of its low pigmentation. Only diode and Nd-Yag lasers can be used on dark skin, Nd-Yag being also effective on dark skin. As for electrolysis, it can be used on all types of hair and skin, since it does not act on melanin.

Health risks?

These methods are not carcinogenic: the radiation emitted by the machines is not powerful enough to cause DNA damage, sources of cancer.