Hormonal & Sexual Health

Ganirelix

Ganirelix blocks the pituitary's GnRH receptors outright, so the signal to the ovaries stops within hours and returns as soon as dosing stops. Its whole job in an IVF (in vitro fertilisation) cycle is to prevent one specific accident: the body releasing an egg before it can be collected, which would waste weeks of stimulation. It is among the shortest courses in medicine, a daily injection started on day six and a mean of 5.4 days in total, and it has been FDA-approved since 1999. In the registrational trial a premature surge occurred in under 1 percent of 463 women, and pooled against the older agonist protocol across randomised trials, live birth rates were the same.

Last updated 12 August 2026

Studied forOvarian stimulation research · LH surge suppression · Assisted reproduction context

Evidence on fileFDA-approved · 2 randomised human trials

Strongest sourceTreatment with the gonadotrophin-releasing hormone antagonist ganirelix in women undergoing ovarian stimulati… (randomised human trial)

Mechanism

Competitively blocks pituitary GnRH receptors, producing rapid, reversible suppression of LH and FSH secretion.

Regulatory status

Approved by the FDA. Marketed as GANIRELIX ACETATE, FYREMADEL. Earliest approval 1999-07-29. Application NDA021057, ANDA204246, ANDA212613, ANDA214996, ANDA215658, ANDA216075, ANDA218855.

An approval grades as rung 1 on this site, because 21 CFR 314.126 requires adequate and well-controlled human investigations and one cannot be granted without them. It covers specific indications and doses, though, and does not transfer to other uses of the same molecule.

Reported effects

What sources associate with this compound. Reported categories, not outcomes we have graded — each would need its own citation and rung.

Ovarian stimulation research
LH surge suppression
Assisted reproduction context

Dosing on file unverified

250 mcg SC QD during mid-late follicular phase until hCG day

Carried from a source that labels it unverified, and reproduced with that label attached. A record of what is reported, not a recommendation. No citation on this page establishes it.

Half-life, storage & sport

Elimination half-life: approximately 13 hours (human, SC) — study. F&S reports 2023; healthy female volunteers of reproductive age, single 0.25-mg dose.

The half-life on file is 13 h, measured subcutaneously. On the schedule this record states — daily — each dose is still at 28% of its own peak when the next is given, so the doses overlap: the peaks build to 1.39× the first.

Dosed daily over 4 d, each dose normalised to the first peak.

The rise is not modelled and the axis is not a blood level. No absorption rate constant and no volume of distribution are on file, so each dose appears at full height the instant it is given, and the axis is percent of this compound's own peak.

Literature on file 3

human RCT
Treatment with the gonadotrophin-releasing hormone antagonist ganirelix in women undergoing ovarian stimulation... [title truncated in API summary] (Human Reproduction 2000, cited 291x) graded on: names a randomised controlled trial — the indexed publication type — “Randomized Controlled”
human RCT
A double-blind, randomized, dose-finding study to assess the efficacy of the gonadotrophin-releasing hormone antagonist ganirelix... [title truncated in API summary] (Human Reproduction 1998, cited 279x) graded on: a randomised study — “randomized, dose-finding study”
human RCT
FDA approval NDA021057, ANDA204246, ANDA212613, ANDA214996, ANDA215658, ANDA216075, ANDA218855 graded on: an FDA approval (NDA021057, ANDA204246, ANDA212613, ANDA214996, ANDA215658, ANDA216075, ANDA218855), which requires adequate and well-controlled human investigations — “NDA021057, ANDA204246, ANDA212613, ANDA214996, ANDA215658, ANDA216075, ANDA218855”

Identity

Space-filling 3D model of Ganirelix, carbon grey, nitrogen blue, oxygen red — Built from the SMILES on this record — the atoms and bonds are exact. The shape is **one computed low-energy pose**, not a measured structure: a flexible peptide in solution has no single conformation, and where the SMILES leaves a stereocentre undefined the pose commits to one arbitrarily. The skeletal formula below claims connectivity and nothing more, which is what we actually know.

2D chemical structure of Ganirelix — Built from the SMILES on this record — the atoms and bonds are exact. The shape is **one computed low-energy pose**, not a measured structure: a flexible peptide in solution has no single conformation, and where the SMILES leaves a stereocentre undefined the pose commits to one arbitrarily. The skeletal formula below claims connectivity and nothing more, which is what we actually know.

Molecular weight: 1570.3
Molecular formula: C80H113ClN18O13
CAS number: 124904-93-4
PubChem CID: 16130957
InChI key: GJNXBNATEDXMAK-PFLSVRRQSA-N
Sequence: XXXSYXLXPA
SMILES: CCNC(=NCCCC[C@H](C(=O)N[C@@H](CC(C)C)C(=O)N[C@@H](CCCCN=C(NCC)NCC)C(=O)N1CCC[C@H]1C(=O)N[C@H](C)C(=O)N)NC(=O)[C@H](CC2=CC=C(C=C2)O)NC(=O)[C@H](CO)NC(=O)[C@@H](CC3=CN=CC=C3)NC(=O)[C@@H](CC4=CC=C(C=C4)Cl)NC(=O)[C@@H](CC5=CC6=CC=CC=C6C=C5)NC(=O)C)NCC
InChI: InChI=1S/C80H113ClN18O13/c1-9-84-79(85-10-2)88-38-17-15-24-60(70(104)94-62(41-49(5)6)71(105)93-61(25-16-18-39-89-80(86-11-3)87-12-4)78(112)99-40-20-26-68(99)77(111)90-50(7)69(82)103)92-73(107)64(44-53-30-35-59(102)36-31-53)97-76(110)67(48-100)98-75(109)66(46-55-21-19-37-83-47-55)96-74(108)65(43-52-28-33-58(81)34-29-52)95-72(106)63(91-51(8)101)45-54-27-32-56-22-13-14-23-57(56)42-54/h13-14,19,21-23,27-37,42,47,49-50,60-68,100,102H,9-12,15-18,20,24-26,38-41,43-46,48H2,1-8H3,(H2,82,103)(H,90,111)(H,91,101)(H,92,107)(H,93,105)(H,94,104)(H,95,106)(H,96,108)(H,97,110)(H,98,109)(H2,84,85,88)(H2,86,87,89)/t50-,60-,61+,62+,63-,64+,65-,66-,67+,68+/m1/s1

Notes unverified prose

FDA-approved (Ganirelix Acetate); DailyMed; Drugs.com; FDA-approved

Not on file 0

All 8 tracked fields hold a value on this record: molecular weight and formula, CAS number, PubChem CID, amino-acid sequence, SMILES, InChI and InChI key.

Counted from the record itself, not from what a source said it was missing. 163 of 188 records still have at least one empty.

Listed prices 1

What 1 shop we track listed for Ganirelix, read from their own public catalogues on 2026-09-14. We take no commission on these and they are not ranked by any payment — how vendors are scored.

Compare prices1 listing from 1 shop

Listed in CAD
Vendor	Size	Price	Per mg
Peptide Shop Canada	5 mg	$103.85 CAD	$20.77/mg

Prices are the vendor's own listing, reproduced with the date we read it — never converted between currencies, and compared per milligram only where the vendor states the vial size.