>>16413321the hair that they transplant into the bald area is from follicles that are resistant to balding. if you've ever seen an old bald man that doesn't shave his head, you know they don't typically go like cueball chromedome bald, they have some hair still, on the lower back part of the skull kinda where cena has shaved his ironically in the OP picture, up to around the ears. these areas aren't as receptive to DHT and as such don't thin and go bald, so transplants take follicles from these regions for the hair they're transplanting. you have to take the pills after surgery not to keep these hairs from falling out, but to prevent further loss because you only have so many follicles to work with.