Why does laser hair removal sessions have to be done 4-8 weeks apart?

Great question.  You are correct that laser hair removal needs to be performed during the active growth phase. Hair goes through 3 cycles, one of which is known as the growth phase.  When you receive a treatment, most of the hair in the growth phase will be effectively treated by the laser and those hair follicles will stop producing hair.  However, not all hair is on the active growth phase at any given time.  Depending on the body part, the hair phases change about every 4-8 weeks. If you treat too soon after a laser session, new hairs will not have entered the active growth phase making the treatment less effective.  Essentially, you would just be retreating the same hairs you had already treated, the ones that the body is still working on eliminating. 

Thank you for your question. At any given time, almost 90% of your hair is in this phase, but because not all of your hair is in this phase at once, it requires several treatments to achieve maximum results. For more information, please get a in person consultation from a board-certified dermatologist. 

thank you for your question. The time that we suggest between laser hair removal  treatments  is to achieve the destruction of as many hair follicles as possible. If you had your treatment two weeks earlier than suggested, your treatment would not be as efficient as it could be. This would probably cause the need for additional treatments and additional costs to you.  I hope this helps. Regards, Dr. DiPasquale