Laser Hair Removal: Is It Really Effective For Life?

Schematically, the skin is made up of 3 layers that overlap:

• The epidermis, the superficial layer which provides a “barrier” function against the outside world.
• The dermis, a thicker middle layer composed mainly of collagen. It is through this layer that blood vessels and nerve endings circulate.
• The hypodermis (deep down) allows, among other things, to act as a shock absorber during shocks.

The hair follicle is a kind of hole that extends from the epidermis to the dermis. They are present everywhere on the surface of the body, except the palms of the hands and the soles of the feet. It is from its base, the bulb, that the hair forms.

Hair growth is a relatively complex system. However, it can be associated with two areas that work closely together. ▪️ The papilla, which is a center located in the dermis, all around the bulb of the follicle. It allows the hair to be held in place by the skin. ▪️ The bulge – not to be confused with the bulb, which produces so-called “stem” cells that migrate to the root of the hair follicle and differentiate into keratinocytes. Once formed, these cells die, forming keratin. They make way for new cells by migrating to the surface.

1. It is this cyclical phenomenon – called keratinization – that is at the origin of hair formation. It is estimated that this growth phase (called the “anagen” phase) allows for growth of around 2 millimeters per week.
2. A second stage (called the “catagen” phase) corresponds to the degradation of the hair. Stem cells no longer reach the bulb, and hair growth stops. This phase lasts 2-3 weeks on average.
3. This is followed by a relatively long resting phase (between 2 and 4 months), during which the elements responsible for hair growth (respectively the papilla and the bulb) remain dissociated and at a standstill. Chemical phenomena involving numerous proteins will be at the origin of the formation of a new hair, according to the same mechanisms described above, at the origin of the loss of the previously formed hair

Hair has several roles. Mainly, it protects:

• against UV rays by forming a thick barrier that prevents direct contact of these rays with the skin
• against germs and dust by forming a grid at the entrance to the different orifices (nose, ears, eyes)

Some studies show a link between irritation and hair removal in certain areas of the body (particularly the genitals), with an increased risk of infection.

• About thermal regulation, in the event of heat, the hair retains perspiration. This helps to cool the body and prevents rapid dehydration. Conversely, in the event of intense cold, the hair allows for greater effectiveness in shivering, and therefore optimal heat retention.

There are many methods for removing these hairs. Here’s a quick overview:

Shaving vs. waxing

• When you shave the hair, you cut it.
• When you wax hair, you pull it out.

So, in the first case, the hair is still present (although shortened). In the second case, only the bulb remains – the origin of the formation of the new hair. The main consequence is the impression of faster regrowth when shaving (only the externalized area is removed). Note, however, that during regrowth, the diameter of the hair does not change from one method to another. It is the thicker appearance, due to the “clean cut” of the hair during shaving, that changes.

Hair removal cream

The principle is simple. Hair removal cream is composed of a chemical agent that is harmful to keratinocytes, which—remember—are the main constituents of hair. After applying this cream, the hair is “softened” by the active ingredient: it can be removed without forcing. Beware, however, of allergic risks!

Pulsed light vs. laser hair removal

Mainly, their power. While pulsed light sends a beam whose spectrum is in the visible range (dark red), the medical laser sends an infrared light invisible to the naked eye, and much more powerful. While hair removal by pulsed light may seem less risky at first, it is not. Indeed, it is quite difficult to know precisely the wavelength used, which poses a risk of burns, especially when the operator is inexperienced…

Also note the presence of the sale, in open access, of pulsed light hair removal devices for home use. These have an even more limited power! More regular use is therefore necessary for these devices to see results. However, care must be taken to scrupulously respect the safety instructions indicated by the manufacturer (to avoid untimely burns or even depigmentation of areas of skin).

The principle of laser hair removal is based on the destruction of the germinal centers that make up the hair follicle (especially the bulb). This reduces these areas to simple scar tissue. The laser works, depending on its power, like a physical agent. It allows you to “burn” the key areas for hair regrowth. One subtlety remains: to be effective, the hair must absorb the laser rays. This is why this technique is reserved for people with “dark” hair (they are loaded with melanin, a physiological pigment). The main target of the laser is this pigment, since it will retain the light and diffuse it in the form of heat. This will “thermo-coagulate” the bulb, little by little. As you will have understood, the darker the hair, the more light it absorbs. The treatment is therefore more likely to work! Once the session is over, multiple rednesses are observed in the areas targeted by the laser: this is perifollicular edema. It demonstrates the effectiveness of the session. Several sessions are necessary, since the laser works on hairs that are in a “growth” phase (anagen phase). A delay of several months is necessary, the time for the other hairs to return to this phase. This allows us to recruit a maximum number of hairs between sessions for maximum effectiveness.

Is laser hair removal permanent, for life?

Almost! If the treatment is completed and the safety conditions are met (fair skin + thick, pigmented hair), the majority of hair should not grow back. According to figures put forward by various clinics in charge of this type of procedure, nearly 80% of hair is eliminated once the sessions are finished. The remaining hair is often quite fine and not very pigmented (hence a “fine fuzz” impression that is not very disturbing). Finally, note that some bulbs can reactivate! Hence, the need (put forward by some practitioners) to carry out “maintenance sessions” spaced several months apart.