Views: 21 Author: Site Editor Publish Time: 2020-06-02 Origin: Site
A kind of hair removal in modern medicine and beauty mainly uses the selective photothermal effect of laser to make laser of a specific wavelength pass through the epidermal layer, so that the melanin in the hair follicles can selectively absorb this laser, thereby generating thermal effects and causing hair follicle necrosis. Hair no longer grows.
Laser hair removal is suitable for people with light skin and fine and dark hair. In short, the whiter the skin, the more suitable for laser hair removal
You can use laser hair removal for all skin tones between 1-3. It is recommended not to use laser hair removal for other skin tones.
Reason: Laser hair removal is not perfect, because it is most suitable for people with light skin and dark hair. The diagnosis and treatment range is locked in "dark pigment". If your skin is dark, the laser will destroy the skin pigment and form white spots or dark spots. It often takes months of effort to gradually recover. A few people with dark skin may have light brown freckles after laser hair removal diagnosis and treatment. This is a kind of skin reaction to laser diagnosis and treatment. Since only a few people occur, it is related to the individual's special constitution.
Hair growth cycle
Hair is divided into growth phase, regression phase and rest period (sleep period). Laser hair removal is only effective for hair in the growing phase. When the hair is in the growth period, the cell activity is strong, the melanin is aggregated, and the absorption rate of light reaches 75%, and for the degeneration and rest periods, laser hair removal cannot completely remove the hair in these periods. Therefore, if you want to complete the laser hair removal to get a better hair removal effect, it usually takes 3-5 times to truly achieve permanent hair removal.
(1) Growth period
Also known as the growth-type active period, the growth period can last 4-6 years, or even longer, the hair is actively proliferating, the lower hair bulb cells divide faster, the upper hair bulb cells differentiate into the cortex, the hair scalp; the hair nipple increases, Cell division is accelerated and the number is increased. The original inactive melanin grows dendrites and begins to form melanin.
(2) Retreat period
Also called atrophy period or degeneration period, it lasts 2-3 weeks. The active hair growth ceases, forming a club-shaped hair, with eosinophilic homogeneous material at the lower end, and a bamboo stick shape around the circumference. The inner hair root sheath disappeared, the outer hair root sheath gradually keratinized, the hair bulb flattened, and did not dent, the hair papilla gradually shrunk, and the number of cells decreased. The black cells lost their dendrites and were round again, but inactive.
(3) Sleep period
Also known as the resting period or rest period, it lasts about 3 months. At this stage, the hair follicles gradually shrink, forming a growth-phase hair ball near the aging hair follicles, and finally the old hair falls off, but at the same time there will be new hair growth and then enter the growth phase and repeat the cycle. 9% -14% of the hair in the scalp is in the dormant period, only 1% is in the degenerative period, and 90% of the eyebrows are in the dormant period.