Believe it or not, these days it's possible to use a laser to encourage hair growth. The practitioner uses a low-power micro-laser to stimulate the blood flow in the hair follicles. It's more a way to keep the hair you have than a hair replacement method, but it can be an effective complementary therapy.
The bald truth about hair replacement tonics and medications is that almost none of them work. Only minoxidil (Rogaine) and Propecia actually stimulate hair growth, and they don't work for everybody. No other supplements known at this time can regrow hair.