Principles of laser hair removal

Laser hair removal must be performed very accurately by high performance machines and experienced practitioners to obtain good results.

After 25 years of evolution, the laser hair removal technology has become completely mature and is becoming common practice, replacing little by little the previous techniques such as electrocoagulation. And yet, many people remain sceptical, but even worse, some patients have tried permanent hair removal and have been disappointed by the bad results they obtained. Three factors are responsible for such a distressing situation:

- the public’s lack of information

- the unbridled marketing of depilatory devices by manufacturers

- the very unclear and sometimes inappropriate regulations.

We have also assisted to the proliferation of « institutes » and other non medical businesses that display inappropriate devices and insufficient skills and thus remove more money from wallets than hair from the skin. Patients who went to such institutes often obtained bad results and always presented hair regrowth.

It is high time for things to evolve and for patients to have the possibility to be informed correctly! We will thus describe fully the technique for you to share our enthusiasm and our confidence in such a technology.

Laser hair removal is characterised by a close interdependence between the materials and the practitioner. A real chain can be formed from the optical fibre delivering the laser light to the hair itself, and the quality of its links must be as high as possible. It is a bit as in a car race: running an excellent car is essential, but the race will not be won without a good pilot and a team of experienced technicians.

Laser hair removal: how does it work?

Let’s start from the beginning to describe the principle of laser hair removal, called selective photothermolysis. A very complicated word to express the idea that the heat generated by the infrared laser beam on the bulb will damage the reproductive cells of the hair and induce permanent hair removal. The hair is thus astutely cauterized…by itself, as laser light is instantly turned into heat when absorbed by melanin pigments (the skin heats up following the same principle when it is exposed to sunlight). So, the laser will selectively heat up structures containing melanin only, that is the hair but also possibly the skin if it is tanned, which can induce burns. A phototype is a skin type. A dark skin has a high phototype. Dark skins are defined as phototype III, and black skins as phototype IV.

What are the risks of laser hair removal?

Contrarily to the sun blue or ultraviolet rays which may induce cancerous lesions, the infrared rays delivered by hair removal lasers can only provoke heat-induced lesions, which are always perfectly reversible. The only “risk” is thus linked to the principle of laser hair removal itself: that is burns if the skin has been exposed to the sun. Even if such lesions are called burns, they remain benign and very superficial, as they only affect an extremely thin layer of cells.

A brownish spot called burn spot appears on the skin surface, and a very thin layer (little crust) falls after a few days, leaving a light mark on the skin, as the suntan will have been literally scoured. In any case, the skin will tan again easily and will be recoloured after a few weeks. We even noticed that the heat generated on the dermis by the laser stimulated the fibroblasts, so that new collagen was created, thus retightening the skin tissue and improving significantly the skin grain!

An advance as compared to electrolysis

The laser allows to treat big skin areas very rapidly as hair are not treated individually anymore. The skin surface must be covered homogenously with laser spots measuring between 10 and 15 mm in diameter. Underarms are treated in a few minutes, half-legs in 30 to 45 minutes. Laser pain is inferior to that induced by hair electrocution – which can reach completely intolerable levels. The laser sensation is comparable to a slight sting, similar to that of acupuncture needles, and is significantly softened by anaesthetic creams such as the EMLA cream.

The possible secondary lesions induced by laser are always reversible, whereas burns and pigmentation disorders induced by electrolysis are long-lasting and sometimes permanent. In short, the two techniques remain complementary, but nowadays, the indications for electrolysis are limited to the treatment of white or very light-coloured hair, which does not contain any melanin and can thus not be heated by the laser.

© 2003 - 2008 Guide de l'Epilation laser. Publisher CLV. Any copy or reproduction, partial or complete, of the present website on any other server or device for the purpose of reproducing it ulteriorly or redistributing it ulteriorly is formally prohibited by the regulations in effect and can lead to severe civil and penal sanctions.

The four golden rules of laser hair removal

Hairs are only remnants of evolution and as any other primitive structure are also very resistant and will not give in easily. The physiological constraints of the hair (that is how it absorbs the laser beam energy and the amount of energy required to destroy germinal cells) will define the technical constraints for the devices used.

Thus, only a class IV medical laser will treat hair successfully.

Laser hair removal Rule 1:

Class IV laser and medical treatment by an experienced laserist, as nothing can replace the experience of the technician, who must take into account – notably - the phototype, the pigmentation and the diameter of the hair, the characteristics of the area to be treated, the regrowth cycle, the laser pulse time, the energy to deliver (fluence), the shooting rate, and the cooling system!

Laser hair removal is thus both a science and an art, and even the best practitioners will obtain sometimes unsuccessful results that will stimulate their inventiveness to find a protocol that would be more appropriate to difficult cases. But which laser type to choose?

Laser hair removal Rule 2:

Use a laser adapted to the hair type. The Ruby lasers are now outdated, so what is there left?

The diode lasers:

Which have the advantage of being both portable and not very expensive. They are efficient at the beginning of the treatment on thick hair, but the laser beam generates less heat than a Ruby or Alexandrite laser, and the hair removal generally becomes inefficient quite rapidly.

The Nd-Yag lasers:

Elaborated in the USA to treat dark or black hair. These lasers do not allow permanent hair removal, but are a good compromise for patients with high phototypes that cannot undergo permanent hair removal. A maintenance session once or twice per year is better than no treatment at all.

Flash lamps:

Have been questioned a lot. They are not really lasers, but simply strong lamps. They are used in skin rejuvenation, but do not provide satisfying results in hair removal as their power and skin penetration is very limited, their ergonomics mediocre and their cooling system nearly absent. Moreover, these “pulsed lights” should be handled exclusively by medical experts, but – alas – a law breach enables anybody to use them, which implies – according to us – a big risk for patients.

The Alexandrite laser:

Remains the “Rolls Royce” of hair removal. But it is space wasting, necessitates an independent electrical installation, and is expensive both to buy and to operate, so that many physicians decide to choose other devices. And yet, it is the best choice and we greatly recommend it for its power, its numerous functions and the comfort it provides to the patient. These terms imply efficiency, comfort and safety.

The next link in the chain is the skin cooling system associated to the laser device. Only a very efficient cooling system will enable the laser to use full power without damaging the skin.

Laser hair removal Rule 3:

Use an efficient skin cooling system. Ice and other gels applied on the skin have been replaced by more efficient processes.

Projections of cryogenic spray. But this technique has many disadvantages: the gas creates a deposit on the skin that absorbs most of the laser energy, the spraying sessions are expensive and slow, which results in a longer laser treatment.

Constant air flow systems are very popular. The Criojet – probably the best device on the market – blows air cooled at a -60°C temperature! Thus, the skin is protected constantly, before, during and after the laser shot.

Finally, our last point, but not the least, concerns the recent technologies that have developed with alexandrite lasers in the domain of shooting systems. The treatment of blond patients can now be envisaged completely serenely.

Laser hair removal Rule 4:

Be treated, if possible, with a laser equipped with the latest innovations.

The choice of the “pulse time”. This parameter is similar to a car transmission: it enables to choose the laser energy delivery speed. It proves the laser can adapt to all types of patients.

The intermittent shot enables to deliver the energy through short impulses and to respect the skin even more while the hair accumulates heat.

You are now able to make a reasonable choice between the different offers available on the market. You can also compare the prices of the sessions according to the devices proposed. A powerful device will not only guarantee satisfying results but also reduce the amount of sessions to reach such a result.