Hair growth cycle
Hair is divided into Anagen (Growing phase) , catagen (Transition phase) and Telogen (Resting phase). Laser hair removal only works on hair in the growth phase. When the hair is in the growth phase, cell activity is strong, melanin accumulates and the light absorption rate reached 75%. However, for the categen and resting phase, laser hair removal cannot completely remova the hair in these phases. Therefore, in order to achieve better hair removal results, it usually takes 3-5 times to truly achieve permanent hair removal.
Anagen:
It is also called the growth active phase, which can last 4-6 years, or even longer. The hair is actively proliferating, the cells in the lower part of the hair bulb divide faster, and the cells in the upper part of the hair bulb differentiate into cortex ad hair cuticles; the hair papilla increases, cell division accelerates and the number increases. The originally inactive melanin grows dendritic processes and begins to form melanin.
Catagen:
It is also called the transition phase, which can last 2-3 weeks. Active hair growth stops, forming a club-like hair with an eosinophilic homogeneous substance at its lower end and a bamboo stick shape around it. The inner hair root sheath disappears, the outer hair root sheath gradually becomes flat and becomes indented, the dermal papilla gradually shrinks and the number of cells decreases. The black cells lost their dendritic processes and became round and inactive
Telogen:
Also known as the resting phase, which lasts for about 3 months. At this phase, the hair follicles gradually shrink and re-form an anagen hair ball near the aging hair follicles. Finally, the old hair falls off, but at the same time, new hair will grow and then enter the anagen phase and repeat the cycle. 9%-14% of the hair on the scalp is in the resting phase, only 1% is in the catagen phase, and 90% of the eyebrows are in the resting phase.
laser hair removal times
To gain smooth skin through laser hair removal, you need to know that the number of times laser hair removal is different for different parts of the body. Generally, armpit hair, leg hair and arm hair need 3-5 sessions. And people with thin lip hair takes about 7 sessions of laser hair removal to remove. Some people are curious and ask why the number of times is different in different pars. This is mainly because the hair in different parts respond differently to treatment. The best interval between laser hair removal sessions is 30 to 45 days, because it usually takes 30 to 45 days for hair follicles to go from the regression phase to the growth phase.
In addition, the frequency of laser hair removal is determined by each person’s original body hair. Generally, if people with thick hair undergo laser hair removal, it will take more times than ordinary people to completely solve the hair problem.
