• Laser Hair Removal
• General Information
• Hair Removal Methods

WHAT FACTORS CONDITION LASER HAIR REMOVAL?

Melanin density of the hair follicle: since melanin is the laser’s target, the greater the concentration of melanin and the greater proximity to the hair matrix means, the greater the efficacy of the treatment. This is why grey hair or slightly pigmented hair is not removed by laser.

Melanin density of the skin: We must not forget that there is also melanin in the epidermis. The more tanned the skin is, the more difficult hair removal becomes due to the greater risk of secondary effects. It is important to determine the skin phototype (see Table 1) to decide on the most appropriate laser. The highest phototypes present a higher risk of burning, which is why they require the use of lasers with a greater wavelength and long pulse duration. For this same reason it is not recommended to perform laser sessions if the skin has been recently exposed (one month) to ultraviolet radiation (sun or UV rays) or self-tanning lotions.

Densidad de melanina en la piel: no debemos olvidar que en la epidermis también existe melanina. Por ello, cuánto más morena es la piel, más difícil es la depilación por el mayor riesgo a presentar efectos secundarios. Es importante determinar el fototipo de piel (ver tabla 1) para determinar el láser más adecuado. Los fototipos más altos son los que presentan mayor riesgo de quemadura por lo que requieren el empleo de láseres de mayor longitud de onda y de duración de pulso largo. Por este motivo se recomienda no realizar sesiones de láser si la piel ha sido expuesta recientemente (un mes) a radiación ultravioleta (sol o rayos UVA) o se ha empleado autobronceadores.

Table 1:

SKIN PHOTOTYPES

-Very sensitive (red-haired Celtics). They always burn and never tan.

- Very sensitive (fair-skinned Caucasians). They burn easily and barely tan.

- Sensitive (dark-skinned Caucasians). They sometimes burn and always tan (light brown).

- Moderately sensitive (Mediterranean Caucasians). They burn minimally and always tan (brown).

- Minimally sensitive (Latin Americans). They rarely burn and always tan (dark brown).

- Insensitive. They never burn, intense pigmentation (black).

Hair thickness: the thicker and more pigmented the hair, the greater absorption of energy and the more efficient hair removal becomes. Fine hair absorbs less energy and is more difficult to remove.

Depth of the hair follicle: it is important to consider the depth of the hair follicle in order to determine the use of a laser with a greater or lesser penetration. For more superficial hair, such as facial hair, shorter wavelength lasers are used. For deeper hair, such as back hair in males, longer wavelength lasers are more appropriate.

Growth phase: the best results are obtained in the anagen phase, when the hair is thicker and more pigmented. However, some authors have not found differences in the response to laser in the anagen and telogen phase. For this reason the target of the laser is stem cells in the protuberance, which is an area unaffected by hair cycles.

Hair follicle density: a greater density requires a smaller dose of energy or several sessions of hair removal to avoid overheating the area.

Age and sex: these are factors that condition hair removal due to the hormone status of the patients. Androgens (male hormones) make the treatment difficult, which is why male hair is harder to eliminate and requires a greater number of sessions. Women with hormone imbalances and hormone dependent body-areas (areola, linea alba, chin) are also harder to treat.

Topography: there’s no doubt that certain areas respond a lot better to hair removal than others. In women, these areas include armpits, bikini line and legs. The facial area is more complex due to greater follicle density in fine hair. On the other hand, hormone variations in women, especially those in menopause, make facial hair removal transient since new hair appears as time goes by.