If you have thin hair all over your head it probably won’t work because the hair is just being moved around. If the hair is thick in one area and thin in another as with males experiencing male pattern baldness then the thick area can be harvested for transplants, thinning it, and the thin area can be transplanted and it will be thicker, and an overall more even density all over the head can be achieved. The method is called follicular unit extraction(F.U.E.)or the Wood’s method. Australian Dr. Ray Wood’s pioneered the method. Single hairs are harvested from the thicker area and transplanted to the thin area. There are no scalpels used and no cutting as with the old "strip extraction surgery" harvesting method still being performed by most doctors. This left an 8-10 scar for every strip extraction. And strip extractions were limited by scalp tightness. Since there is no cutting, only a topical aneshtetic is used. You can learn more about it on Dr. Alvi Armani’s and Dr. Woods website and many others:
http://www.alviarmanihairtransplant.com/
http://www.woodstechnique.com.au/