Gonadotropin Releasing Hormones Agonists Overview

Gonadotropin releasing hormone agonists (GnRH) are a type of medication that suppresses ovulation by stopping the production of estrogen and progesterone.

Doctor holding injection
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Gonadatropin releasing hormone is a naturally occurring hormone in the body. It is released by the hypothalamus and it controls the release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) from the pituitary gland. These hormones FSH and LH then stimulate the production of estrogen and progesterone in the ovaries. It is this relationship known as the hypothalamic pituitary ovarian axis that controls your menstrual cycle.

In order for this axis to function properly and result in ovulation, GnRH has to be released in a pulsatile fashion. If this axis is functioning properly you will have regular periods if you didn’t get pregnant when you ovulated.

GnRH Agonist Medications

The class of medications known as GnRH agonists exploits this need for pulsatile secretion of GnRH. The medication results in a continuous stimulation of the pituitary gland. At first, there can be a brief surge of FSH and LH release but then the non pulsatile concentration of GnRH causes the pituitary gland to stop producing FSH and LH, which ultimately turns off hormone production in the ovary.

The three GnRH agonists commonly used in clinical practice are:

  • Lupron - leuprolide
  • Zoladex - goserelin
  • Synarel - nafarelin

Leuprolide and goserelin are administered by injection in doses for every 4 weeks or 12 weeks while nafarelin is administered by a nasal spray 1-2 times daily.


Because GnRH agonists temporarily turn off your ovaries production of estrogen and progesterone this class of medications is used to treat certain conditions in women that are estrogen and progesterone dependent. These include:

There is also some evidence to suggest that GnRH agonists may also help preserve ovarian function in women undergoing chemotherapy for breast cancer.

Side Effects

These medications are very effective treatment options. Unfortunately, they have some significant side effects. Because they suppress your ovaries production of hormones, the side effects of GnRH agonists mimic the symptoms of menopause. These side effects include:

  • Hot flashes
  • Vaginal dryness
  • Decreased libido
  • Headache
  • Fatigue
  • Mood disturbances
  • Decreased bone mineral density

To prevent the loss of bone associated with GnRH treatment your healthcare provider will likely prescribe a progestin or a combination of estrogen and a progestin. This is known as add-back therapy and it has been shown to be effective in preventing the bone loss associated with extended use of GnRH agonists. It also may help reduce the severity of the hot flashes as well.

6 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Ohlsson B. Gonadotropin-Releasing Hormone and Its Role in the Enteric Nervous System. Front Endocrinol (Lausanne). 2017;8:110. doi:10.3389/fendo.2017.00110

  2. Magon N. Gonadotropin releasing hormone agonists: Expanding vistas. Indian J Endocrinol Metab. 2011;15(4):261-7. doi:10.4103/2230-8210.85575

  3. Food and Drug Administration. Lupron Depot.

  4. Food and Drug Administration. Synarel.

  5. Rossi L, Pagani O. The Role of Gonadotropin-Releasing-Hormone Analogues in the Treatment of Breast Cancer. J Womens Health (Larchmt). 2018;27(4):466-475. doi:10.1089/jwh.2017.6355

  6. Joffe H, White DP, Crawford SL, et al. Adverse effects of induced hot flashes on objectively recorded and subjectively reported sleep: results of a gonadotropin-releasing hormone agonist experimental protocol. Menopause. 2013;20(9):905-14. doi:10.1097/GME.0b013e31828292d1

By Tracee Cornforth
Tracee Cornforth is a freelance writer who covers menstruation, menstrual disorders, and other women's health issues.