Can a Person Run out of Hair for Hair Transplants?

I don’t get it!!! Doesn’t every strand of hair for men have a genetic life cycle that eventually runs out in some areas?? (Hairline, crown). How can a male have unlimited replenishment of hair?

Good question. In every one of us who is balding, the pattern of balding we inherit determines the extent of the permanent hair on the side and back of the head. Because we can’t predict the pattern we inherited with absolute certainty, I assume that only the fringe area in a Class 7 patient is the permanent area. This area has a finite amount of hair (about 20% of the total birth hair population on the scalp). You can have this 20% area (called the donor area) harvested over and over again until the area has lost 50-70% of its hair density. Then, the donor area is depleted and no more hair can be harvested without producing balding in this area around the back and side of your head.  Each hair has both a hair cycle (Anagen and Telogen) and a limited number of hair cycles that it can have in your lifetime.  For the balding Class 7 patterned patient (with only 20% of his hair remaining in a rim around the back and sides of the head), the hair that was lost underwent apoptosis (an effective cell death). These men often have fewer than 10 hair cycles (as few as 6-7) of their anagen/telogen cycle. We know that these hairs, which are absolutely gone to the naked eye, are actually in some stem cells located where each hair used to be. One day, some doctor/researcher will find the switch to turn on these hair stem cells to create new hair. I believe we may actually see this breakthrough in the next few years.