FOLLISTIM CARTRIDGES REQUIRE A FOLLISTIM PEN (REUSABLE DELIVERY MECHANISM). THESE ARE AVAILABLE FOR PURCHASE ON THIS SITE. Follitropin Beta (puregon) is a gonadotrophin hormone and consists of highly purified rFSH (recombinant follicle stimulating hormone) with neither urinary proteins nor LH (lutenising hormone). Since it is very pure, Puregon (Follitropin Beta) is used to treat fertility problems. It is used in combination with Pregnyl (hCG - human chorionic gonadotrophin) to stimulate the ovaries in women or used alone to stimulate sperm production in men.