Decapeptyl contains triptorelin and temporarily switches off your own hormone signalling. That gives side effects many women find surprising: hot flushes, headache, poor sleep and dry mucous membranes. They resemble menopause symptoms, and that is no coincidence.
The drug does something different from the rest of your schedule. Where Gonal-f or Menopur switch your ovaries on, Decapeptyl first puts the brake on.
What does Decapeptyl do in your body?
Decapeptyl is a GnRH agonist. It occupies the receptors in your pituitary that normally give the starting signal for FSH and LH. In the first days that actually causes a brief surge, after which the pituitary becomes unresponsive and your own production falls silent.
That silence is exactly what the clinic wants. Without your own LH surge you cannot ovulate spontaneously before the retrieval is scheduled.
Your oestrogen level drops considerably in that phase, which explains the menopause-like complaints. Once stimulation starts and your oestradiol rises again, they usually ease.
The long protocol: when do you get Decapeptyl?
In the classic long protocol you start Decapeptyl about a week before your expected period and continue until the trigger. FSH stimulation begins only once suppression is confirmed.
There are also depot forms, where one injection works for several weeks, and short protocols that deliberately use the initial surge.
| Long protocol with agonist | Antagonist protocol | |
|---|---|---|
| Drug | Decapeptyl and similar agonists | Antagonists, later in the cycle |
| Start | Usually in the cycle before | During stimulation |
| Duration | Longer, often several weeks | Shorter |
| Typical side effects | Menopause-like complaints | Less pronounced |
| Risk of hyperstimulation | Higher than with antagonist | Lower (PMID 27126581) |
| Chance of a live birth | No difference shown |
Follow your own clinic schedule. This table is here to help you understand why your schedule looks the way it does.
Is the long protocol worse than an antagonist protocol?
Not for your chance of a baby, but it does carry more hyperstimulation risk. A Cochrane review of 36 randomised trials found antagonist protocols cause less hyperstimulation than long agonist protocols, with an odds ratio of 0.61, without lowering the chance of a live birth (PMID 27126581).
Concretely: where the risk with an agonist protocol sat around 11 percent, with an antagonist protocol it came out at roughly 6 to 9 percent.
That is honest information, not a reason to panic. Clinics deliberately choose the long protocol in certain situations, for example with endometriosis or after an earlier cycle that turned too soon.
It is a good question for your consultation though: why was this protocol chosen for me? There should always be a reason.
Side effects of Decapeptyl
The side effects reported most are hot flushes, headache, mood swings, sleep problems, vaginal dryness and reduced libido. They fit the low oestrogen level during suppression.
Injection site reactions also occur, and sometimes light bleeding at the start. The Farmacotherapeutisch Kompas also lists joint complaints and fatigue.
In most women the complaints ease once stimulation starts and oestradiol rises again. That is the point at which many women feel noticeably better.
Contact your clinic with severe abdominal pain, a quickly swelling belly, vomiting or shortness of breath. That does not belong to the suppression phase.
Decapeptyl experiences: what do users report?
This is the drug that generates the most stories, and that is down to the hot flushes. Women often describe it as a few weeks of early menopause.
What women mention positively:
- The complaints usually disappear once stimulation starts
- The injection itself is small and quick
- With a depot form you only inject once
- It is reassuring that the cycle can no longer turn on its own
What they find heavy:
- Hot flushes, especially at night
- A short fuse and low mood
- Poor sleep, which amplifies the rest
- Headache in the first week
Picture two women of 34 both doing a long protocol. One mainly notices she sleeps worse and throws the duvet off at night. The other has barely any flushes but a short fuse for two weeks. Both are themselves again after stimulation starts.
Which values does the clinic check?
Before stimulation starts, the clinic checks whether suppression worked. That is done with an ultrasound and often with oestradiol, which should be low at that point.
After that it is about the rise: oestradiol up, follicles larger, and LH and progesterone low enough to prevent you ovulating early.
If you want to know your baseline, you can have an estradiol test or the broader IVF blood test, assessed by a BIG-registered doctor. Read also Gonal-f and the stimulation phase, Ovitrelle as a trigger and the full IVF route.
Frequently asked questions
Where do you inject Decapeptyl?
Usually under the skin of your abdomen or thigh, depending on the form you have. Depot forms are sometimes given into a muscle. Follow the instruction from your clinic.
What time should you inject Decapeptyl?
With a daily form, usually at roughly the same time each day. For a trigger there is an exact time your clinic names. When in doubt, rather call once too often.
How long do the hot flushes last?
Usually as long as suppression lasts, so until stimulation gets going. In most women they clearly ease within a few days of starting FSH. If they stay severe, report it.
Can Decapeptyl put you into the menopause?
No, the effect is temporary and your own cycle returns after stopping. The complaints resemble menopause symptoms because your oestrogen is low, but your ovaries are not depleted by it.
What if you forget an injection?
Call your clinic the same day. A missed dose can break through the suppression and disrupt the schedule. Never double up yourself.
This is the drug where I would genuinely factor the side effects into your planning. Two weeks of poor sleep is not a small thing, certainly not alongside a treatment schedule. At your intake, ask explicitly why a long protocol was chosen for you, and whether an antagonist protocol was also an option in your situation. That conversation belongs in the process.
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. Triptorelin. Accessed 2026.
- Thuisarts.nl. I am having IVF. Accessed 2026.
- 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.
- 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.
Autor
Lunarahealth
Dr. Naimi, lekarz wpisany do holenderskiego rejestru BIG, nadzoruje standardy medyczne naszych treści i ocen. Przeczytaj naszą politykę medyczną
