Peptide Graded

All peptides / Reproduction

Cetrorelix

GnRH antagonist

Also Cetrotide, Cetrorelix acetate, SB-75, Cetrorelix pamoate

Evidence
AStrong human evidence
FDA status
FDA approvedas of 2026-10-26
Route
Injection
Studies cited
2 human0 animal or cell

A fertility drug that stops the body releasing eggs too early during IVF. It has been well tested in people and works as well as older options.

Sold for

Cetrorelix is a routine IVF drug and carries little hype; where it appears outside fertility clinics it is discussed as a way to switch off sex-hormone production quickly.

Studies say

Dozens of randomized trials show GnRH antagonist protocols give the same live-birth rate as agonist protocols with fewer cases of ovarian hyperstimulation, which supports an A for the fertility use.

Why grade A. The approved IVF use rests on randomized trials of cetrorelix itself plus a Cochrane review of GnRH antagonists in assisted reproduction that pooled 73 randomized trials with 12,212 women. The review found live-birth rates equal to the older agonist protocols and a lower rate of ovarian hyperstimulation syndrome. The single cetrorelix trial in the citations is a multicentre randomized study from 2000 in 154 women, which compared one late-follicular injection with a depot GnRH agonist. 43

FDA. Cetrorelix is FDA-approved as Cetrotide (cetrorelix acetate for injection), first approved in August 2000, for the inhibition of premature LH surges in women undergoing controlled ovarian stimulation. 1

Written from 4 cited sources. Fact-checked 2026-10-27: 16 claims checked, 3 corrected. Last refreshed 2026-10-27. Not physician reviewed.

What this means for you

What people take it for
Fertility treatment (IVF)
Can a US doctor prescribe it?
Yes, FDA approved for use in IVF to stop eggs being released too early.
Properly tested in people?
Yes, in large controlled trials; one review covered 73 trials and 12,212 women.

Evidence checklist

  • Randomised controlled trial Randomized trials, Cochrane review of 73yes
  • Human study over 100 people Review pooled 12,212 womenyes
  • More than one research group Many trial groups across countriesyes
  • Clinical outcomes, not surrogate markers Live birth and OHSS rates comparedyes
  • Human safety data beyond case reports Label data, decades of useyes

Drawn from the cited studies below. A dash means the sources give no information.

What it is

Cetrorelix is a lab-made peptide of ten amino acids (a decapeptide). It is built to compete with gonadotropin-releasing hormone. That is the brain signal that tells the pituitary to release LH and FSH. Cetrorelix is in the GnRH antagonist class. Ganirelix and degarelix are in the same class. 2

In the United States, EMD Serono sells it as Cetrotide. Patients inject it under the skin. They do this while the ovaries are being stimulated in an IVF cycle. 1

How it works

During ovarian stimulation, injected FSH makes several follicles grow. Rising estrogen would normally trigger a surge of LH. That surge releases the eggs before they can be collected. Cetrorelix blocks the GnRH receptor on pituitary cells. LH release is suppressed within hours of the first injection. The clinic then controls the timing of ovulation with a separate trigger shot. GnRH agonists such as leuprolide cause an initial hormone flare. Antagonists do not, and they need only a few days of treatment. 21

What human research shows

A multicentre randomized study published in 2000 gave 115 IVF patients one injection of cetrorelix in the late follicular phase. Another 39 got a depot of the agonist triptorelin. No LH surge occurred in any cetrorelix patient. Pregnancy rates did not differ significantly. The cetrorelix group needed shorter stimulation. It had less ovarian hyperstimulation syndrome. Fewer eggs were collected, though. The label describes this single-dose regimen. It also describes a daily low-dose regimen from the phase 3 program. The US now supplies only the daily low-dose form. 31

A 2016 Cochrane review compared GnRH antagonist and long GnRH agonist protocols across 73 randomized trials and 12,212 women. Live birth did not differ (odds ratio 1.02, 12 trials, 2,303 women, moderate-quality evidence). Ovarian hyperstimulation syndrome of any grade was less common with antagonists (odds ratio 0.61, 36 trials, 7,944 women). 4

StudyModelFinding
Cochrane review, GnRH antagonists in ARTHumans, 73 RCTs, n=12,212 women, systematic reviewSame live-birth rate as agonist protocols; lower odds of ovarian hyperstimulation syndrome. 4
Single-dose cetrorelix phase IIIHumans, n=154 women undergoing IVF, multicentre randomized, versus depot triptorelinOne injection in the late follicular phase prevented premature LH surges in every cetrorelix patient, with similar pregnancy rates to the agonist. 3
FDA label, CetrotideRegulatory summary of clinical trialsApproved for inhibition of premature LH surges during controlled ovarian stimulation. 1

Safety

The most common effects on the label are injection-site reactions such as redness, itching and swelling. Nausea and headache also occur. Ovarian hyperstimulation syndrome can still occur, because the FSH stimulation drives it. The Cochrane review found it less often with antagonist protocols. Allergic reactions including anaphylaxis have been reported. The drug must not be used in pregnancy. 14

Long-term safety data on children born from antagonist cycles have shown no warning signs. But the review says this outcome is reported less often than live birth. 4

Questions for your clinician

  • Why was a GnRH antagonist chosen over an agonist protocol for my cycle?
  • How is my risk of ovarian hyperstimulation being monitored?
  • What injection-site reactions are common and when should I report them?

Questions people ask

Is cetrorelix FDA-approved?

Yes, as Cetrotide. It was approved in 2000 to prevent early LH surges in women having controlled ovarian stimulation for assisted reproduction. 1

How is cetrorelix different from leuprolide?

Both shut down the pituitary's LH and FSH output, but by opposite routes. Leuprolide is an agonist. It first stimulates the receptor and then wears it out, which takes a couple of weeks and causes a hormone flare. Cetrorelix blocks the receptor directly. Suppression starts within hours, and a few days of injections are enough. 24

Does the antagonist protocol lower IVF success?

Pooled data from 12 randomized trials with 2,303 women found no difference in live birth between antagonist and agonist protocols. Antagonist cycles had fewer cases of ovarian hyperstimulation syndrome. 4

What reactions should patients expect after injections?

Mostly redness, itching or swelling at the injection site. Nausea and headache were also reported. Ovarian hyperstimulation can still occur because the stimulation drugs cause it. Rare allergic reactions have been reported. 1

Citations

  1. FDA label, 2023: Cetrotide (cetrorelix acetate for injection) accessdata.fda.gov
  2. DrugBank DB00050: cetrorelix go.drugbank.com
  3. Olivennes 2000, Fertil Steril: single-dose cetrorelix in controlled ovarian stimulation doi.org
  4. Al-Inany 2016, Cochrane: GnRH antagonists for assisted reproductive technology doi.org

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