These days, it’s pretty easy to find articles online that walk you through numerous fertility protocols, from in-vitro fertilization (IVF) to egg freezing. But what about all the questions that pop up for each step of those protocols? Like, say, what’s it like to take Ganirelix — a hormone medication administered during ovarian stimulation? Can you really be sure you’re getting correct, medically informed answers from the internet?

Unfortunately, it’s just as easy to stumble upon articles that contain misinformation, especially if you’re asking Dr. Google. Enter Roon, a free platform comprised of short-form video content providing accurate health and fertility information through their interdisciplinary team of top medical experts, including reproductive endocrinology and infertility specialists (REIs) and embryologists. The platform, accessible via either Roon’s website or iOS app, contains around 4,000 answers to your fertility-related questions on IVF, egg freezing, IUI, surrogacy, PCOS, male factor infertility, or even mental health. 

So, what should we know about Ganirelix? Rescripted spoke with Amanda Adeleye, M.D., a reproductive endocrinologist and medical director at CCRM Fertility in Chicago — and one of Roon’s medical experts — who explained exactly what we can expect from this particular medication. 

woman inejecting herself with ganirelix

What is Ganirelix, and why is it prescribed during IVF?

Ganirelix is an injectable medication that can help prevent early ovulation for people undergoing ovarian stimulation for either egg freezing or IVF.

“Nowadays, people doing ovarian stimulation for egg freezing or IVF most often use an ovulation blocker like Ganirelix,” explains Dr. Adeleye. “The purpose is to help ensure that the eggs are ready to be collected around the same time.” 

Ganirelix is a gonadotropin-releasing hormone antagonist. It works by preventing luteinizing hormone (LH) surges (which in turn would trigger ovulation). The medication is administered once a day under the skin of your stomach or thigh during the mid-to-late follicular phase, usually around Day 7 or 8, but, depending on the case, it can be injected up to Day 12 or 13 of the menstrual cycle.

Patients will typically take Ganirelix for the duration of their ovarian stimulation, “with their last dose being the day of the ‘trigger shot,’” says Dr. Adeleye.

doctor and patient discussing ganirelix

Potential side effects of Ganirelix

Most Ganirelix side effects are minor and don’t require medical intervention. “Some side effects of Ganirelix include reactions such as redness, burning, or irritation at the injection site,” says Dr. Adeleye. “Any of these side effects in isolation that are mild and go away on their own, don’t necessarily need to be reported right away.”

Dr. Adeleye goes on to say that some people do report headaches and/or nausea as well. While those symptoms may not be related to Ganirelix, they should be addressed by a medical provider regardless. In general, “symptoms that don’t go away or should be further evaluated,” she says. 

It’s also a good idea to be on top of any possible allergies before undergoing fertility treatments: “People that have an allergy to Gainirelix or any of the ingredients,” says Dr. Adeleye, “should not be prescribed [this medication]. If you are allergic to Ganirelix, the initial reaction may be mild, but it is possible that with repeated doses, your response could become more severe and warrant immediate treatment.”

woman injecting herself in the belly with ganirelix

What else should patients know about Ganirelix?

“Making sure that your follicles are growing and responding together is critical for most ovarian stimulation cycles,” advises Dr. Adeleye, so it’s important to follow all your doctor’s instructions for your Ganirelix injections. You also may want to consider setting a daily reminder on your phone: “The medication doesn’t last in your body for that long,” explains Dr. Adeleye, “so taking the medication around the same time of day every day is important to achieving the goal of having the most mature eggs your body can produce in a single cycle.”

If you have additional questions about Ganirelix, don’t ask Dr. Google. To receive the most medically accurate answers to your fertility questions, speak to your medical provider or head over to, where you can find answers to all of your questions from experts like Dr. Adeleye for free. You can visit the website or download the iOS app right onto your phone.

Sarene Leeds holds an M.S. in Professional Writing from NYU, and is a seasoned journalist, having written and reported on subjects ranging from TV and pop culture to health, wellness, and parenting over the course of her career. Her work has appeared in Rolling Stone, The Wall Street Journal, Vulture, SheKnows, and numerous other outlets. A staunch mental health advocate, Sarene also hosts the podcast “Emotional Abuse Is Real.” Visit her website here, or follow her on Instagram or Twitter.