How to Use Cetrorelix
Complete guide to Cetrorelix dosing, administration, timing, and protocol recommendations.
Quick Overview
Cetrorelix is a GnRH antagonist: a modified 10-amino-acid version of the brain's gonadotropin-releasing hormone that blocks its receptor instead of activating it. Sold as Cetrotide and FDA-approved since August 2000, its job in IVF is narrow and important: it stops the body's own LH surge from releasing eggs too early while the ovaries are being stimulated. It is a well-established fertility drug with decades of use, and it is not a tool for anything else people sometimes imagine it for.
Dosing Guidelines
Common Dose
0.25 mg once daily during IVF stimulation (labeled dose)
Frequency
Once daily
Dose Range
0.25 mg daily; a single 3 mg dose regimen was also studied
Note: Labeled prescription dose, used only inside a monitored IVF cycle alongside gonadotropins and ultrasound tracking. Timing of the hCG trigger and stopping is set by the fertility clinic. Using it outside that setting has no established benefit.
Administration Method
Subcutaneous injection in the lower abdomen; can be self-administered after instruction, first dose under medical supervision
Best Time to Take
Same time each day, starting stimulation day 5 or 6
The label starts it on stimulation day 5 (morning or evening) or day 6 (morning) and gives it every 24 hours, because the 0.25 mg dose suppresses LH for about a day.
Protocol Duration
A few days per IVF cycle (median 5 days in trials, range 1-15)
Possible Side Effects
Not everyone experiences these. Individual responses vary.
- •Injection site reactions (redness, bruising, itching, swelling)
- •Ovarian hyperstimulation syndrome (3.5% moderate or severe in trials, linked to the overall IVF stimulation)
- •Nausea
- •Headache
- •Hypersensitivity reactions, including anaphylactoid reactions with the first dose (rare)
Frequently Asked Questions
What is the recommended dose for Cetrorelix?
0.25 mg once daily during IVF stimulation (labeled dose)
How do you administer Cetrorelix?
Subcutaneous injection in the lower abdomen; can be self-administered after instruction, first dose under medical supervision
When is the best time to take Cetrorelix?
Same time each day, starting stimulation day 5 or 6
How long should you use Cetrorelix?
A few days per IVF cycle (median 5 days in trials, range 1-15)
This information is for educational purposes only. Always consult with a healthcare professional before using any peptide. Dosing information is based on research literature and community reports, not medical advice.