Cetrorelix

GnRH Antagonist

Also known as: Cetrotide

A GnRH antagonist that immediately suppresses LH & FSH without the initial testosterone flare seen with GnRH agonists. Used in IVF & is under study for BPH.

Typical Dose

0.25 mg/day SubQ or 3 mg single dose

Route

Subcutaneous injection

Cycle

Per IVF protocol (typically 4–6 days)

Half-life

~62 hours (3 mg dose); ~12 hours (0.25 mg dose)

Storage

2–8°C.

Overview

Cetrorelix is a synthetic decapeptide GnRH antagonist that competitively blocks GnRH receptors on pituitary gonadotrophs, immediately suppressing LH & FSH secretion without causing the initial hormone surge ('flare') associated with GnRH agonists. It is FDA approved for controlled ovarian hyperstimulation in IVF.

Quick Start Guide

Clinical use in IVF. Administered 0.25 mg SubQ daily or 3 mg as single dose.

Research Indications

Controlled ovarian hyperstimulation (IVF)

Most Effective

FDA approved. Prevents premature LH surge during ovarian stimulation without the flare associated with GnRH agonists.

Research Protocols

IVF LH suppression

4–6 days

Dose

0.25 mg/day

Frequency

Daily from stimulation day 6 to HCG trigger

Route

SubQ

Side Effects & Safety

Common

Injection site reactions
Nausea
Headache

Uncommon

Ovarian hyperstimulation syndrome

When to Stop

Signs of OHSS
Signs of allergic reaction

How to Reconstitute

Reconstitute with supplied diluent per package insert.

Dosing math: Commercial product.

Quality Indicators

Good — use as normal

Clear solution per manufacturer

Discard immediately

Any deviation

What to Expect

Day 1–6

Immediate LH suppression without flare. Ovarian stimulation continues unimpeded.

Community Insights

Self-reported. Reflects user experience, not clinical outcomes.

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Information on this page applies to pharmaceutical-grade peptides. Purity & identity of research-grade products vary. Certipep provides independent ESI-TOF-MS & HPLC analysis with a signed analytical report.

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