Laser Hair Removal

In the 1990s, laser technology made great progress in medical cosmetology. Scientists used laser technology to successfully apply the principle of "selective photothermal effect" to hair removal.

Due to the abundant melanin in hair follicles and hair shafts, melanin is distributed between the cells of the hair bulb matrix and can also be transferred to the structure of the hair shaft. Lasers with specific wavelengths can target melanin for precise and selective hair removal treatment. After the melanin absorbs the energy of the laser, the temperature rises sharply, causing the destruction of the surrounding hair follicle tissue, and the hair no longer grows. According to the theory of selective photothermal action, as long as the appropriate wavelength, pulse width, and energy density are selected, the laser can precisely destroy the hair follicle without causing damage to adjacent tissues.

Due to the deep location of the hair follicles, it is decided to use light sources with longer wavelengths and deeper penetration for treatment. The spectrum with a wavelength of 600-1 100 nanometers can penetrate the depth of the hair follicle and be well absorbed by melanin, which is the ideal wavelength range for laser hair removal. In addition, the ideal laser pulse width should be between the thermal relaxation time of the epidermis and the thermal relaxation time of the hair follicle. The thermal relaxation time of the epidermis is 3-10 milliseconds, and the thermal relaxation time of the hair follicle is 40-100 milliseconds. The ideal pulse width range is 10~100 milliseconds or even longer.

The energy density of the laser should be the maximum energy density that the patient can tolerate without obvious side effects. The laser treatment head is equipped with a cooling device to protect the skin, so the skin will not be damaged during the hair removal treatment, and reactions such as abnormal pigmentation or scars will not occur.

How to avoid side effects?

There are different degrees of tingling sensation during the treatment, but they are all tolerable. Erythema or follicular papules may appear immediately in the treated area, which will resolve spontaneously. 1 to 3 days after treatment, the purpura may appear in the treatment area of individual patients. If the energy density is too high, blisters and erosions may appear in the treatment area. Temporary hyperpigmentation or hypopigmentation can occur, most of which can recover after a few months, and very few permanent hypopigmentation can occur.

With the continuous development of laser equipment, laser hair removal will bring people more comfortable and efficient treatment. Choosing a regular hospital, under the treatment of experienced doctors, can reduce the occurrence of side effects and bring more ideal cosmetic results.