Cetrorelix
Also known as: Cetrotide, Cetrorelix acetate
Key Facts: Cetrorelix
- Category
- Hormonal
- FDA Status
- FDA Approved
- Clinical Status
- FDA Approved - Cetrotide 0.25 mg (NDA 021197, approved August 11, 2000; EMD Serono) for inhibition of premature LH surges in women undergoing controlled ovarian stimulation. Also authorised in the EU. Failed phase 3 trials in benign prostatic hyperplasia (2009).
- Banned in Sport (WADA)
- Not on the WADA Prohibited List (2026). S2 bans GnRH and its agonist analogues in males, but antagonists like cetrorelix are not listed, and as an approved drug it is not caught by S0.
- Administration
- Subcutaneous injection in the lower abdomen; can be self-administered after instruction, first dose under medical supervision
- Typical Dose
- 0.25 mg once daily during IVF stimulation (labeled dose)
- Frequency
- Once daily
- Duration
- A few days per IVF cycle (median 5 days in trials, range 1-15)
How does Cetrorelix work?
The pituitary releases LH and FSH in response to GnRH. Cetrorelix competes with natural GnRH for the pituitary receptor and shuts that signal down within hours (about 2 hours for the 0.25 mg dose), with a stronger effect on LH than FSH. Unlike GnRH agonists such as leuprolide, there is no initial flare of hormone release, so it can be started mid-cycle rather than weeks ahead. The effect is reversible once dosing stops. In IVF this prevents a premature LH surge, which would otherwise trigger ovulation before the eggs can be retrieved. Because the same signal drives testosterone in men, a GnRH antagonist suppresses testosterone, which is the opposite of what anyone seeking an anabolic effect wants.
What does the research show?
The FDA approval rests on five trials covering 732 women. In phase 3, the multiple-dose 0.25 mg regimen and a single 3 mg dose regimen each prevented premature LH surges in nearly everyone (LH surge rates of 0-1.9%), with clinical pregnancy rates around 20-23% per attempt, typical for IVF at that time. Larger phase 3b experience (Olivennes and colleagues, 2003, over 1,600 women) found the two regimens similar, with severe OHSS in under 1% of cycles. The best overall evidence on antagonists as a class is the 2016 Cochrane review (73 trials, over 12,000 women): compared with the older long GnRH-agonist protocol, antagonists gave similar live birth rates but substantially less ovarian hyperstimulation syndrome. That is why antagonist protocols became standard in many clinics. Outside IVF, cetrorelix was tested for benign prostatic hyperplasia, but two phase 3 trials in 2009 found it no better than placebo, and that program was dropped.
FDA Approval Studies
This peptide is FDA approved. Below are the key clinical trials that supported its approval.
Cetrotide phase 3 program (single 3 mg and multiple 0.25 mg regimens)
ASTA Medica (now EMD Serono) • Phase 3
732 women across five phase 2 and 3 trials (577 in the three phase 3 studies)
One controlled ovarian stimulation cycle
Prevention of premature LH surge during controlled ovarian stimulation
- ✓Premature LH surge in 0-1.9% of patients
- ✓hCG given in 96-98% and oocyte pick-up in 93-98%
- ✓Clinical pregnancy rate about 20-23% per attempt
- ✓Median 5 days of multiple-dose treatment
What doses have been studied?
Typical Dosingⓘ
Community experience
0.25 mg once daily during IVF stimulation (labeled dose)
0.25 mg daily; a single 3 mg dose regimen was also studied
Once daily
Labeled prescription dose, used only inside a monitored IVF cycle alongside gonadotropins and ultrasound tracking. Timing of the hCG trigger and stopping is set by the fertility clinic. Using it outside that setting has no established benefit.
Research Dosingⓘ
Scientific studies
FDA-approved labeled dosing (prescription only, used within an IVF cycle)
Doses from Studies
0.25 mg once daily from stimulation day 5 or 6 until hCG
FDA Approved Labeling - Cetrotide 0.25 mg prescribing information ↗
0.25 mg daily (multiple dose) or single 3 mg dose
Phase 3b trials - Olivennes et al., Reproductive BioMedicine Online 2003 ↗
Duration
A few days per IVF cycle (median 5 days in trials, range 1-15)
Administration
Subcutaneous injection in the lower abdomen; can be self-administered after instruction, first dose under medical supervision
When and how is Cetrorelix taken?
Best Time to Take
Same time each day, starting stimulation day 5 or 6
Once daily until the day of the hCG trigger
Food Recommendation
With or without food
Why This Timing?
The label starts it on stimulation day 5 (morning or evening) or day 6 (morning) and gives it every 24 hours, because the 0.25 mg dose suppresses LH for about a day.
What are the side effects of Cetrorelix?
Not everyone experiences these effects. Individual responses vary based on dosage, duration, and personal factors.
- ●Injection site reactions (redness, bruising, itching, swelling)
- ●Ovarian hyperstimulation syndrome (3.5% moderate or severe in trials, linked to the overall IVF stimulation)
- ●Nausea
- ●Headache
- ●Hypersensitivity reactions, including anaphylactoid reactions with the first dose (rare)
- ●Contraindicated in pregnancy and breastfeeding
- ●Suppresses LH and testosterone in men (not an anabolic)
References
- https://www.accessdata.fda.gov/drugsatfda_docs/label/2023/021197s017s022lbl.pdf
- https://www.ema.europa.eu/documents/product-information/cetrotide-epar-product-information_en.pdf
- https://pubmed.ncbi.nlm.nih.gov/27126581/
- https://pubmed.ncbi.nlm.nih.gov/12831588/
- https://www.fiercebiotech.com/biotech/aeterna-zentaris-announces-results-from-two-phase-3-studies-cetrorelix-benign-prostatic
Research This Peptide Further
Frequently Asked Questions
What does Cetrorelix do?
Cetrorelix is a GnRH antagonist: a modified 10-amino-acid version of the brain's gonadotropin-releasing hormone that blocks its receptor instead of activating it. Sold as Cetrotide and FDA-approved since August 2000, its job in IVF is narrow and important: it stops the body's own LH surge from releasing eggs too early while the ovaries are being stimulated. It is a well-established fertility drug with decades of use, and it is not a tool for anything else people sometimes imagine it for.
How does Cetrorelix work?
The pituitary releases LH and FSH in response to GnRH. Cetrorelix competes with natural GnRH for the pituitary receptor and shuts that signal down within hours (about 2 hours for the 0.25 mg dose), with a stronger effect on LH than FSH. Unlike GnRH agonists such as leuprolide, there is no initial flare of hormone release, so it can be started mid-cycle rather than weeks ahead. The effect is reversible once dosing stops. In IVF this prevents a premature LH surge, which would otherwise trigger ovulation before the eggs can be retrieved. Because the same signal drives testosterone in men, a GnRH antagonist suppresses testosterone, which is the opposite of what anyone seeking an anabolic effect wants.
Is Cetrorelix FDA approved?
Yes, Cetrorelix is FDA approved. FDA Approved - Cetrotide 0.25 mg (NDA 021197, approved August 11, 2000; EMD Serono) for inhibition of premature LH surges in women undergoing controlled ovarian stimulation. Also authorised in the EU. Failed phase 3 trials in benign prostatic hyperplasia (2009).
Is Cetrorelix banned in sport?
Not on the WADA Prohibited List (2026). S2 bans GnRH and its agonist analogues in males, but antagonists like cetrorelix are not listed, and as an approved drug it is not caught by S0.
What are the side effects of Cetrorelix?
Reported side effects include: Injection site reactions (redness, bruising, itching, swelling), Ovarian hyperstimulation syndrome (3.5% moderate or severe in trials, linked to the overall IVF stimulation), Nausea, Headache, Hypersensitivity reactions, including anaphylactoid reactions with the first dose (rare). Individual responses vary based on dosage, duration, and personal health factors.
What is the typical dose of Cetrorelix?
Community-reported common dose: 0.25 mg once daily during IVF stimulation (labeled dose) (Once daily). Range: 0.25 mg daily; a single 3 mg dose regimen was also studied. Administration: Subcutaneous injection in the lower abdomen; can be self-administered after instruction, first dose under medical supervision. Prescription drug. Dose set by prescriber per label. Not medical advice.
Related Peptides
Peptides commonly compared with Cetrorelix or used in similar applications.
Leuprolide
FDALeuprolide (brand name Lupron) is a synthetic GnRH agonist, a modified peptide far more potent than natural GnRH, and it is FDA-approved for advanced prostate cancer, endometriosis, uterine fibroids, and central precocious puberty. The clever part is counterintuitive: it works by overstimulating the GnRH system so hard that the pituitary shuts down sex hormone production. It is a real, long-established prescription drug (first US approval 1985), not a research peptide, and it carries meaningful side effects from the low-hormone state it creates.
HormonalOctreotide
FDAOctreotide is a synthetic eight-amino-acid mimic of the natural hormone somatostatin, the body's main 'off switch' for hormone secretion. It shuts down excess growth hormone, so it is a frontline FDA-approved drug for acromegaly, and it also tames the flushing and diarrhea of hormone-secreting carcinoid and other neuroendocrine tumors. This is real, approved medicine with decades of clinical data behind it, sold as Sandostatin (injectable, since 1988), Sandostatin LAR (monthly depot), and Mycapssa (oral capsule, approved 2020).
HormonalLanreotide
FDALanreotide (development code BIM-23014) is an eight-amino-acid somatostatin analog, a close cousin of octreotide, given as a long-acting deep-injection gel (Somatuline Depot/Autogel) usually once a month. The FDA approved it for acromegaly in 2007, for gastroenteropancreatic neuroendocrine tumors in 2014, and for carcinoid syndrome in 2017. Generic versions now exist alongside Ipsen's Somatuline Depot. It is established prescription medicine, not an experimental compound.
HormonalPegvisomant
FDAPegvisomant (brand name Somavert) flips the usual acromegaly strategy on its head: instead of telling the tumor to make less growth hormone, it blocks growth hormone's receptor on target tissues directly. It is a PEGylated, genetically modified version of human growth hormone that acts as a receptor antagonist, FDA-approved in 2003 for acromegaly patients who do not respond well to surgery or other drugs. It is the single most effective option for normalizing IGF-1, which is why it is a key second-line therapy.
HormonalMacimorelin
FDAMacimorelin (brand name Macrilen) is an orally active ghrelin receptor agonist used as a diagnostic test, not a treatment. You drink a single dose, then doctors measure how much growth hormone the pituitary releases to diagnose adult growth hormone deficiency. It was FDA approved in December 2017 as the first oral diagnostic agent for that condition.
HormonalHMG
FDAHMG (human menopausal gonadotropin, sold as menotropins under the brand Menopur) is a purified hormone mix extracted from the urine of postmenopausal women. Each standard vial carries 75 IU of FSH activity and 75 IU of LH activity, with most of the LH activity coming from hCG. It is an FDA-approved fertility drug used to stimulate egg development in IVF, and it is also used, mostly off-label in the US, together with hCG to kick-start sperm production in men whose pituitary does not make enough FSH and LH. This one has decades of real clinical use behind it.
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