Evidence review: Open Peptide Project (verified against primary PubMed, ClinicalTrials.gov & FDA records) · Last checked 2026-10-27. ← Back to Evidence Library
Ganirelix (Antagon / Orgalutran / Fyremadel): what the evidence says
At a glance
What it is: a synthetic 10-amino-acid GnRH receptor antagonist. FDA approved it under NDA 021057 (Organon). R1
What the evidence says: in IVF, it blocks the early LH surge with shorter treatment than long agonist protocols, with similar pregnancy rates. R2, R3 Compared with leuprolide, results were similar. R4
Biggest risks: injection-site reactions; ovarian hyperstimulation was 2.4% vs 5.9% with buserelin in one trial. R2
Rating
| Human Human evidence | Strong: multicenter RCTs, n = 313 and 355 R4, R3, plus a buserelin-controlled RCT R2 UNVERIFIED that trial's size |
| Animal Animal / lab evidence | Not reviewed |
| Regulatory | FDA-approved (NDA 021057) R1 · not on FDA's 503A or 503B bulk-substance category lists and not on FDA's compounding safety-risk page R5, R6, R7 · not named by WADA R8 |
| Established human dose | Yes, label dose |
Evidence verdict: Preventing early LH surge in IVF: Strong (FDA-approved) · Other uses: No good human data
This page reports what studies used. It is not dosing advice.
Legend: HUMAN data · ANIMAL / LAB data · UNKNOWN · UNVERIFIED: not yet confirmed against a primary source
About the evidence: several randomized IVF trials. Pregnancy rates were similar or slightly lower than with agonist protocols.
What is it?
Related pages: Cetrorelix, Degarelix, Leuprolide, Gonadorelin, Kisspeptin-10.
Does it work?
- Human vs buserelin (2000): ongoing pregnancy 20.3% vs 25.7% per attempt. R2
- Human vs leuprolide (2001, n = 313): 11.6 vs 14.1 eggs retrieved; similar fertilization. R4
- Human vs triptorelin (2001): 9 vs 26 treatment days, similar outcomes. R3
- Unknown Hormone or testosterone uses outside IVF: no good data.
Is it safe?
- Human Well tolerated in IVF trials; lower hyperstimulation than buserelin. R2
Gray-market vials: extra risks
A gray-market vial has no quality control and no guarantee of identity, strength or sterility. We test retail vials blind under the Open Peptide Standard; see /tests/. A passing test covers one batch on one date and does not mean the compound is safe.
Is it legal?
- US: FDA-approved prescription drug; generics exist. R1 UNVERIFIED the Fyremadel brand's application number.
- Compounding: not on FDA's 503A or 503B bulk-substance category lists and not on FDA's compounding safety-risk page. R5, R6, R7
- Sport: not named on WADA's 2026 Prohibited List. R8
Study details
Study details
These are amounts researchers used, not recommendations.
| Study | People / model | Route | Amount used | Follow-up | Reported | Citation |
|---|---|---|---|---|---|---|
| vs buserelin 2000 | Women in IVF/ICSI | SC daily | 0.25 mg | One cycle | Pregnancy 20.3% vs 25.7% | PMID 10875855 |
| vs triptorelin 2001 | 355 women | SC daily | 0.25 mg | One cycle | Comparable outcomes | PMID 11278211 |
Full reference list (PubMed, CT.gov, FDA and WADA checked Oct 26, 2026)
- R1 Drugs@FDA, Ganirelix acetate (Organon), application NDA 021057 (openFDA drugsfda record checked Oct 26, 2026). https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm?event=overview.process&ApplNo=NDA 021057
- R2 Borm G, et al. Hum Reprod. 2000. PMID 10875855
- R3 European and Middle East Orgalutran Study Group. Hum Reprod. 2001. PMID 11278211
- R4 Fluker M, et al. Fertil Steril. 2001. PMID 11163814
- R5 FDA, 503A bulk drug substances categories list (updated May 14, 2026). https://www.fda.gov/media/94155/download
- R6 FDA, 503B bulk drug substances categories list (updated Mar 21, 2025). https://www.fda.gov/media/94164/download
- R7 FDA, Certain bulk drug substances for use in compounding that may present significant safety risks (content current Apr 22, 2026). https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks
- R8 WADA. The 2026 Prohibited List, full list checked; compound not named. https://www.wada-ama.org/sites/default/files/2025-09/2026list_en_final_clean_september_2025.pdf
Disclaimer
This page is for education and harm reduction, not medical advice or a recommendation to use Ganirelix (Antagon / Orgalutran / Fyremadel). This is a prescription medicine. Use it only under the care of a licensed clinician; do not buy it from research-chemical or gray-market sellers. Report problems to FDA MedWatch (https://www.fda.gov/safety/medwatch).