Laser hair removal is a successful application of the principle of selective photothermal action. That is, the melanocytes in the hair follicle absorb light in a specific wavelength band (610-950 nm), convert the laser energy into heat energy, and generate instantaneous high heat locally in the hair follicle, thereby achieving the effect of destroying the hair follicle tissue and removing the hair; at the same time, it avoids damage to the surrounding tissue. At present, the most commonly used hair removal in the world are semiconductor laser, long-pulse alexandrite laser, long-pulse alexandrite laser, and Intense Pulsed Light (IPL).

The hair growth cycle has three stages: growth phase, regression phase and telogen phase. Under normal circumstances, about 70% to 85% of the hair is in the growth phase. The hair matrix cells in the growing period have high division activity, full of melanin, and are easy to absorb light of special wavelengths, while the hair follicles in the degenerative and resting periods have less melanin content and poor ability to absorb light waves. Therefore, laser hair removal is only suitable for Only effective hair is in the growing phase. According to the condition of hair growth, after 3 to 6 treatments for the hair in the growth phase, the hair follicles in different growth phases are destroyed successively, so as to achieve the purpose of permanent hair removal.

The effect of hair removal is related to various factors such as hair quality, hair follicle depth, laser wavelength, skin type, and treatment site, so the same treatment parameters can produce different treatment effects. Generally speaking, the thicker the hair and the darker the color, the lower the treatment parameters, the more obvious the treatment response, the better the hair removal effect, and the fewer treatments. Conversely, hair removal is less effective, but permanent hair removal can still be achieved after repeated treatments.

In general, the effect of hair removal on the upper lip is the worst, which may be related to the thinner lip hair and fewer target chromophores; in addition, the hair growth period is short and the hair growth period is less. With the increase of the number of treatments, the hair removal rate gradually increased, and the hair regeneration cycle was prolonged, indicating that the effect of hair removal treatment was positively correlated with the number of treatments.

Some People Will Ask Whether Laser Hair Removal Will Affect Perspiration?

In fact, there is a misunderstanding here, we refer to body hair as fine hair. I think hair and sweat glands go together. In fact, hair follicles and sweat glands are two separate tissues. The eccrine sweat glands that secrete sweat open separately on the surface of the skin. Although the two are adjacent, they are not one body, and there is not a lot of melanin in the sweat glands. These specific wavelengths of light have almost no effect on the eccrine glands, so laser or photon hair removal will not interfere with normal perspiration.