Cetrorelix Products | Cleanchem - Cetrorelix is a gonadotropin-releasing hormone (GnRH) antagonist used in fertility treatments to prevent premature ovulation in women undergoing in vitro fertilization (IVF). It works by inhibiting the release of luteinizing hormone (LH), preventing premature ovulation. Cetrorelix is typically used in controlled ovarian stimulation protocols. Side effects may include headaches, abdominal pain, and injection site reactions.