In my work with The Endometriosis Network Canada, I have heard many women say that their doctors told them that if their pain does not go away on Lupron, then the pain must not be from endometriosis. Lupron never has and never will be an effective tool for diagnosing whether pain is due to endometriosis. Not only does Lupron have the potential for significant side effects, which alone should abrogate its use as a diagnostic tool, but it also is not at all effective at diagnosing endometriosis and distinguishing it from other conditions.
Lupron is a synthetic version of a naturally occurring hormone called gonadotropin-releasing hormone, and its action is actually stronger than the naturally occurring GnRH. It is a long-acting medication that initially stimulates hormones in the pituitary gland that control the menstrual cycle, and then suppresses these functions. It is typically given as a 1 month or 3 month injection.