Hair growth cycles play a big part in any hair removal treatment routine. A variety of factors can cause excessive hair growth, including stress, medication, heredity, and hormonal changes. In women, puberty, pregnancy, as well as menopause play an important role in determining the growth of hair. Many researchers agree that there may be so many hair follicles, about 2500 of them per square inch, but at any point in time there may be less than a hundred hairs showing. It is for these reason that during a hair removal treatment, it’s very difficult for anybody to predict, including your doctor, the actual length of time it will take for your hair to stop growing after treatment.
Between the time your hair starts growing and falling out a few years later, each strand goes through 3 distinct phases; anagen (or growing phase), catagen (or intermediate/transitional phase) and telogen (or shedding phase).
The anagen stage is also known as “the growing phase”. This is when all-new hair growth happens. During this phase, 9 out of 10 of the head hairs will be growing normally. They’ll grow at an average of 1 inch per month in most individuals. Each specific hair strand may in the “growing” or anagen phase for about 3-5 years, but sometimes for up to 10. Throughout the anagen phase, melanin (pigment) is created in hair follicle. Among older people, less melanin is created during the stage, and that’s why white hair begins to appear even when the hair is growing strong and healthy.
The catagen phase is also referred to as “the transitional phase”. This stage indicates the end of your hair growth phase. During this stage, the hair follicle will contract and detach from the nutritional supply known as the dermal papilla, and form into a round cub. At this stage, there is no melanin (pigment) created and the hair follicle will stop producing hair. The hair follicle then moves upwards towards the skin’s surface. Less than 1 percent of your hair will be in this phase at any point in time. The catagen phase normally lasts only 1-2 weeks.
The telogen phase is also called “the shedding phase”. It is the last stage of the hair growth cycle and lasts until fully-grown hair falls out. This phase normally lasts for 3-4 months. During this period, new hair will start to grow from hair follicles while old hair will start to shed naturally or can be pulled out, easily and painlessly, while brushing or shampooing. At any point in time, about 10 percent of the hair follicles on the head are in the shedding phase. In simple language, 10 percent of your hair is always in the telogen phase. Your new hair emerges from the opening used by the old one, onto the skin’s surface, to start its 3-step cycle all over again.
It is important to note that all the hair on your head and other parts of the body is in different phases at any point in time, so even if your telogen phase is over and old hair is being shed and replaced, it doesn’t necessarily mean that the follicle nearby is. If that was the case, then it would be impossible to maintain the length of your hair.
The 3 different hair growth stages, the anagen (growing phase), catagen (transitional phase) and telogen (shedding phase) are the reason why laser hair removal is done in multiple sessions. The best time to have your hair permanently destroyed is at the anagen (growing phase). It may take 6-12 weeks for a strand of hair to appear from the papilla, or matrix, to the skin’s surface. Thus, if you tweeze a strand of your hair now, it’s impossible to see that same hair in 1 week. The hair growth cycles may vary to some extent from one person to the other, and can leave vastly different individual patterns. LHR only works on growing hair. Multiple sessions spread weeks apart are needed to remove not only the hair that is actively growing now, but to also remove hair that may be currently in the resting phase but will enter the growing phase weeks from now. Patience is going to be key to getting smooth, hairless skin on a more permanent basis.
For a quick illustration of the hair growth cycle check out the great video below.