Gonal-f side effects: how it works, experiences and dosing

The best known side effects of Gonal-f are a red or tender injection site, headache, a bloated belly and tender breasts. They show up mostly in the first days, and they belong to what the drug does: making your ovaries work harder than in an ordinary cycle.

What women rarely hear beforehand is that most complaints do not come from the injection but from your own rising oestradiol. That distinction helps, because it explains why you feel heaviest towards the end of the stimulation.

What does Gonal-f do in your body?

Gonal-f contains follitropin alfa, a laboratory made copy of your own FSH. FSH is the hormone that grows follicles in your ovary every cycle. By injecting it, several follicles grow at once instead of the usual single one.

So you are not given a new hormone your body does not know. You are given more of something you make yourself.

That is exactly why the side effects feel like a magnified version of your normal cycle. More follicles means more oestradiol, and more oestradiol gives the tender breasts and bloating you sometimes also get around ovulation.

Gonal-f injection: how and when do you inject?

Gonal-f is injected under the skin, usually in your abdomen or thigh, with a pen you set to a number of units. Most clinics have you inject at roughly the same time each day, often in the evening, for about 8 to 12 days.

The starting dose differs per woman. Your gynaecologist looks at your age, your AMH and your earlier response, then adjusts based on the ultrasound.

Always follow your own clinic schedule. What follows is meant to help you understand that schedule, not to replace it.

In many schedules Gonal-f does not come alone. In a long protocol you first get a drug that switches off your own signalling, such as Decapeptyl, and stimulation starts only after that.

Recombinant or urinary: does it matter which one you get?

For the chance of a live birth it probably does not, according to the best available studies. A Cochrane review of 42 trials with 9,606 couples found no meaningful difference between recombinant FSH and urinary gonadotrophins, neither in live births nor in hyperstimulation (PMID 21328276).

That is more reassuring than it sounds. Many women wonder whether they were given the more expensive or the cheaper drug, and whether that changes their odds.

The reviewers reached a practical conclusion: choose on availability, convenience and cost. Read our explanation of Menopur and the difference with FSH and of Puregon.

Side effects of Gonal-f

The side effects reported most for Gonal-f are injection site reactions, headache, abdominal pain, bloating, tender breasts and nausea. Redness, itching and small bruises at the injection site occur mainly in the first days and usually fade on their own.

The Farmacotherapeutisch Kompas also lists ovarian cysts and, less often, ovarian hyperstimulation syndrome. That last one is what the monitoring is built around.

Call your clinic if your belly swells quickly, if you have strong abdominal pain, nausea with vomiting, shortness of breath or clearly reduced urine output. Those are the signals not to sit on until your next appointment.

For perspective: severe hyperstimulation is not the norm. A Cochrane review on prevention reported a baseline risk of roughly 27 percent of moderate or severe hyperstimulation in women at raised risk, falling to about 8 to 14 percent with dopamine agonists (PMID 33851429). That figure applies to the high risk group, not to everyone.

Gonal-f experiences: what do users report?

Two things come back repeatedly. The injecting is easier than expected, and the second week is heavier than the first.

What women mention positively:

• The pen is simple, and the needle is thin enough to barely feel
• You inject at home, at a time you choose yourself
• The ultrasound gives concrete progress every few days
• Many women notice almost nothing in the first days

What they find difficult:

• A tight, bloated belly in the last days before egg retrieval
• Headache and poorer sleep
• Emotional peaks, hard to separate from the tension itself
• Planning daily life around a fixed injection time

Picture two women of 33 who both start. One counts eleven follicles after ten days and mainly feels tired. The other has a tight belly after eight days, turns out to have an oestradiol above 9,000 pmol/l and gets an adjusted schedule. Same drug, different response, and that is exactly why monitoring is so frequent.

Which values does the clinic track during stimulation?

Oestradiol and the ultrasound are the two anchors. Oestradiol rises with the number and maturity of your follicles, and the scan counts and measures them. Together they decide whether the dose goes up or down and when the trigger follows.

Clinics often also look at LH and progesterone, to check you are not ovulating early on your own. Before the start, AMH matters most, because it is the best predictor of how many follicles you are likely to make.

If you want to know your baseline before starting, you can have an AMH test or the broader IVF blood test, assessed by a BIG-registered doctor. Our explanation of AMH value by age helps you read that result, and what IVF actually involves lays out the whole route.

Frequently asked questions

How quickly does Gonal-f work?

Your follicles start growing within a few days, but you do not notice it yourself. The first scan is usually around day 5 to 7 of injecting. Most women feel something only in the second week, and mainly the bloating.

How long do you use Gonal-f?

Usually about 8 to 12 days, until your follicles are large enough. The clinic decides that on the scan, not on a fixed number of days. A slow response can take longer.

Where is the best place to inject Gonal-f?

Under the skin of your abdomen, roughly a hand width around your navel, or in your thigh. Change the spot every day, that reduces bruising. Follow the instruction you were given at the clinic.

Does Gonal-f make you gain weight?

Many women gain a few kilos temporarily, mainly from fluid and a fuller abdomen. That usually settles in the weeks after retrieval. Rapid weight gain of more than two kilos in a few days is a reason to call.

Can you exercise during stimulation?

Gentle movement is usually fine, but many clinics advise against intense exercise and jumping once your ovaries enlarge. That relates to the risk of torsion. Check with your own treatment team.

If I were to pass on one thing: do not let the brand on the pen worry you. The studies show the drug itself rarely makes the difference, while your dose and your monitoring do. At the first scan, simply ask what your oestradiol is and how many follicles count. Then you are following your own route instead of someone else on a forum.

Every blood test result includes a professional assessment from a BIG-registered doctor. For treatment decisions, discuss your results with your GP or your gynaecologist.

References

• Farmacotherapeutisch Kompas. Follitropin alfa. Accessed 2026.
• Thuisarts.nl. I am having IVF. Accessed 2026.
• van Wely M, Kwan I, Burt AL, Thomas J, Vail A, Van der Veen F, Al-Inany HG. Recombinant versus urinary gonadotrophin for ovarian stimulation in assisted reproductive technology cycles. Cochrane Database of Systematic Reviews, 2011. PMID 21328276.
• Tang H, Mourad SM, Wang A, Zhai SD, Hart RJ. Dopamine agonists for preventing ovarian hyperstimulation syndrome. Cochrane Database of Systematic Reviews, 2021. PMID 33851429.
• Al-Inany HG, Youssef MA, Ayeleke RO, Brown J, Lam WS, Broekmans FJ. Gonadotrophin-releasing hormone antagonists for assisted reproductive technology. Cochrane Database of Systematic Reviews, 2016. PMID 27126581.