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.
Dosing protocols
| Purpose | Route | Dosage | 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. |
Dosing information is for educational purposes only. Consult a qualified healthcare professional before using any peptide.
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.
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.
Where to get it
Prescription required
Cetrorelix is a prescription medication. Consult your healthcare provider or a licensed telehealth platform for access.