I just "rented" a zapper from a clinic that can tell you exactly which parasites etc you have without even stool samples. I am very happy with them. I discovered I have had giadia lamblia for a while now. This is my second day using the zapper and already I can feel my energy level going up. I am going to use it for a month straight and see what happens. Although I am also in need of a good parasite cleanse. I had a strong reaction to mebendazole medication and was not successful in getting rid of them. Apparently, it's a long process...But so far, yes, happy with the zapper and will keep you posted after longer use.