SYS ONLINE
SUPPLEMENT_SCHOLAR
evidence · mechanism · dose
Experimental/GnRH AntagonistResearch peptide

Ganirelix

aka Antagon · Orgalutran

Another GnRH antagonist used to suppress the LH surge in assisted reproduction.

Educational explainer of a research peptide. Profiles in this section deliberately omit clinical-trial citations, dosing protocols, and purchase links. Not FDA-approved as a supplement; not a recommendation to use.

Overview

Ganirelix is a synthetic decapeptide GnRH receptor antagonist used in assisted reproduction protocols.

Source
  • Approved pharmaceutical
Forms
  • Subcutaneous injection (pre-filled syringe)

Mechanism of action

Competitively antagonizes pituitary GnRH receptors, rapidly suppressing LH and FSH without an initial flare.

Pathways
  • · GnRH receptor antagonism
  • · LH and FSH suppression
Hormones
  • · GnRH
  • · LH
  • · FSH

How it acts on the body

Ganirelix is therapeutically equivalent to cetrorelix and is chosen on cost, schedule, and prescriber familiarity. It is injected daily during the late follicular phase of an IVF cycle to keep the LH surge at bay while follicles mature.

Pituitary recovery is rapid after the last dose, allowing trigger and retrieval to be timed precisely.

Hormonal & endocrine impact

How this peptide is reported to shift specific hormones and signaling molecules. Directionality reflects research literature and preclinical models, not clinical prescribing data.

Projected hormonal trajectory
Illustrative curves derived from reported direction of effect. Not measured patient data.

Curves are schematic shapes (sigmoid for increases/decreases, damped oscillation for modulation/stabilization) anchored to a 100% baseline. They communicate direction and tempo of change reported in research literature — not absolute hormone concentrations.

LHDecreases
Rapid suppression.
FSHDecreases
Modest concurrent suppression.

Effects on the body

Inhibits
Premature LH surge during ovarian stimulation

Organ system effects

Endocrine

GnRH receptor blockade.

Reproductive

IVF cycle control.

Reported effects

Drawn from preclinical research, anecdote, and small-scale clinical observation. No evidence grades are assigned — most peptides on this page lack rigorous human trials.

  • Pre-filled syringe convenience
  • No flare phase

Potential side effects

Common
  • · Injection-site reaction
  • · Mild headache
Rare
  • · Nausea
Serious
  • · Hypersensitivity reactions reported

Drug interactions

No notable interactions reported.

Pairing context

Often combined with
  • Recombinant FSH protocols
    Standard component of antagonist IVF cycles.
Avoid combining with
  • Latex allergy with older syringe formulations
    Check product insert for current formulation.
Important. Research peptides described here are not FDA-approved supplements. Supplement Scholar does not endorse, recommend, or link to any source for purchase. Consult a qualified clinician before considering any peptide therapy.