Answer:
It depends upon the person, genetics, age, hormone level and type of laser. If the amount of energy delivered to the area by a laser is high enough, which is measured in Joules per square centimeter, and the follicle has pigment, then the follicle will be destroyed. To remove hair permanently, the energy must by high enough to destroy both the follicle and the blood supply to the follicle, and then the hair will typically not grow back. Even with electrolysis or laser, if the hormone level is high the hair can grow back. And as everyone knows, sometimes as we age, the body just spontaneously sprouts new hair.