Cetrorelix is a synthetic GnRH antagonist decapeptide (MW ~1431.1 g/mol) FDA-approved for the prevention of premature LH surges in women undergoing controlled ovarian stimulation for IVF. Like ganirelix, it provides immediate GnRH receptor blockade without the hormonal flare of GnRH agonists. Cetrorelix (Cetrotide) is available in both 0.25 mg (daily) and 3 mg (single-dose) formulations, offering flexibility in IVF protocol design. It was one of the first GnRH antagonists developed for reproductive medicine.
Category: Reproductive / Hormonal. Evidence rating: A (strong human clinical data).
Clinical status: FDA-approved (Cetrotide for prevention of premature LH surges in IVF)
Cetrorelix competitively binds to GnRH receptors on anterior pituitary gonadotrophs, immediately blocking the action of endogenous GnRH and suppressing LH and FSH release. This prevents premature LH surges during ovarian stimulation, which would trigger ovulation before oocyte retrieval. The…
Safety considerations: Injection site reactions: redness, itching, and swelling (approximately 4%); Nausea (1.3%); Headache (1.1%).
Reviewed by the PeptideAtlas Editorial Team. Last reviewed: 2026-08-12.
Related peptides: Kisspeptin, Gonadorelin, Oxytocin.
Compare: Cetrorelix vs Kisspeptin, Cetrorelix vs Gonadorelin, Cetrorelix vs Oxytocin.
The 0.25 mg dose is given daily starting on stimulation day 5-7 and continued until the trigger day. The 3 mg dose is given as a single injection on stimulation day 7, providing approximately 4 days of LH suppression. If trigger is not given within 4 days, daily 0.25 mg doses are continued. The single-dose protocol reduces injection frequency but offers less flexibility in stimulation timing.
Both are GnRH antagonists with very similar efficacy and safety profiles for preventing premature LH surges in IVF. Cetrorelix uniquely offers a 3 mg single-dose option in addition to the daily 0.25 mg protocol. Ganirelix is only available in the daily regimen. Clinical outcomes are comparable between the two drugs.
Cetrorelix is FDA-approved only for IVF. It has been investigated in research settings for endometriosis, uterine fibroids, and prostate cancer, but these remain investigational uses. For prostate cancer, dedicated GnRH antagonists like degarelix are approved instead.