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Cetrorelix: quick citable summary
Cetrorelix is listed by PeptaHub as a other peptide with a prescription legal-status classification. The page summarizes mechanism, research context, common routes, safety notes, and references for writers and AI answer engines.
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What is Cetrorelix?
Cetrorelix (Cetrotide) is an FDA-approved GnRH antagonist used in IVF to prevent premature ovulation during controlled ovarian stimulation. It provides rapid LH suppression without the flare effect of GnRH agonists, available in both multidose and single-dose protocols.
Overview
Cetrorelix is a synthetic decapeptide and gonadotropin-releasing hormone (GnRH) antagonist approved by the FDA under the brand name Cetrotide. Used in assisted reproductive technology (ART), it prevents premature luteinizing hormone (LH) surges that would trigger early ovulation before egg retrieval in IVF cycles. It provides rapid, dose-dependent pituitary suppression within hours of administration.
Mechanism of action
Cetrorelix competitively blocks GnRH receptors in the anterior pituitary gland, preventing endogenous GnRH from stimulating LH and FSH release. Unlike GnRH agonists, cetrorelix produces immediate suppression of gonadotropin secretion without an initial flare effect. Receptor occupancy inhibits the LH surge within 2 hours of injection, maintaining follicular development under controlled gonadotropin stimulation. Its decapeptide structure with D-amino acid substitutions confers resistance to enzymatic degradation and high receptor binding affinity, enabling once-daily dosing at 0.25 mg or a single 3 mg dose in IVF protocols.
Reported study ranges
| Purpose | Route | Reported range | Frequency | Notes |
|---|---|---|---|---|
| IVF — multidose protocol | subcutaneous | 0.25–0.25 mg | once daily | Start when leading follicle reaches 12–14 mm diameter (typically stimulation day 5–6). Continue until day of hCG trigger. |
| IVF — single-dose protocol | subcutaneous | 3–3 mg | single injection on stimulation day 7 | If 3 mg dose effect does not last 4 days, supplement with 0.25 mg daily until hCG day. |
Reported ranges are for research context only. Consult a qualified healthcare professional before using any peptide.
Convert Cetrorelix research-range units
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Research summary
Multiple randomized controlled trials demonstrate cetrorelix is non-inferior to GnRH agonist long protocols for IVF, with the advantages of shorter treatment duration, lower FSH requirements, and reduced risk of ovarian hyperstimulation syndrome (OHSS). Meta-analyses confirm comparable live birth rates between GnRH antagonist and agonist protocols. The 0.25 mg daily multidose regimen initiated when follicles reach 12–14 mm has become the clinical gold standard. Cetrorelix is also under investigation for benign prostatic hyperplasia and hormone-sensitive cancers.[1][2][3][4][5]
Evidence grading
Each claimed benefit is graded by the strength of available evidence. Grades reflect study quality, not effect size.
Strong = multiple RCTs · Moderate = limited trials or observational · Preliminary = animal or in vitro only · Insufficient = anecdotal or no published data
Side effects
Side effects vary by individual. This is not an exhaustive list. Report unusual symptoms to a healthcare professional.
Common stacks
Peptides commonly paired with Cetrorelix for synergistic effects.
Legal status
FDA-approved (NDA 021197) for inhibition of premature LH surges in women undergoing controlled ovarian stimulation. Available only by prescription; administered under fertility specialist supervision. Also approved by EMA.
Sourcing & access
Prescription required
Cetrorelix is an FDA-approved prescription medication available through licensed healthcare providers, pharmacies, and label-appropriate access programs; compounded access depends on current FDA shortage status and compounding rules.
Frequently asked questions
Cetrorelix (brand name Cetrotide) is an FDA-approved GnRH antagonist used in assisted reproductive technology (IVF and ICSI) to prevent premature luteinizing hormone (LH) surges that would trigger early ovulation before egg retrieval. By blocking GnRH receptors, it allows precise control of follicular development and oocyte maturation timing during controlled ovarian stimulation protocols.
Cetrorelix competitively blocks GnRH receptors in the pituitary, preventing LH release without the initial hormone flare seen with GnRH agonists. This flare-free suppression occurs within hours of the first dose rather than requiring weeks of downregulation. LH and FSH suppression is rapid and fully reversible upon discontinuation, allowing the IVF cycle to proceed without the lengthy pretreatment period required by GnRH agonist protocols.
In the flexible antagonist protocol, cetrorelix 0.25 mg daily is begun when the leading follicle reaches 12 to 14 mm diameter, typically on day 5 to 6 of stimulation. In the fixed protocol, it starts on day 5 or 6 regardless of follicle size. An alternative single-dose protocol uses 3 mg on day 7 or 8, providing sustained suppression for approximately 4 days without daily injections.
The most common side effects are injection site reactions (redness, bruising, itching) at the daily injection sites. Systemic effects may include nausea, headache, and abdominal discomfort. Mild ovarian hyperstimulation syndrome (OHSS) can occur, though the antagonist protocol is associated with lower OHSS rates than GnRH agonist protocols. Hot flashes may occur briefly during use due to temporary estrogen fluctuation.
Research references
- The LHRH antagonist cetrorelix: a reviewPubMed
- The use of a GnRH antagonist (Cetrorelix) in a single dose protocol in IVF-embryo transfer: a dose finding study of 3 versus 2 mgPubMed
- Tailoring the GnRH antagonist cetrorelix acetate to individual patients' needs in ovarian stimulation for IVF: results of a prospective, randomized studyPubMed
- GnRH antagonist, cetrorelix, for pituitary suppression in modern, patient-friendly assisted reproductive technologyPubMed
- GnRH antagonist versus long GnRH agonist protocol in poor responders undergoing IVF: a randomized controlled trialPubMed