Triptorelin acetate is a potent LHRH agonist. It can result in downregulation of LH and FSH levels followed by a suppression of ovarian and testicular steroid biosynthesis. For most prostate cancers, they need the hormone testosterone in order to grow. Almost all testosterone in men is made by the testicles. Triptorelin stops the testicles from making testosterone. This reduces testosterone levels and may shrink the prostate cancer or stop it growing.