Cetrorelix and Degarelix are each a gnrh antagonist.
They last very different lengths of time. Cetrorelix is gone in About 5 hours at 0.25 mg, about 63 hours at 3 mg; Degarelix stays active for About 53 days. That is why the schedules look nothing alike.
| Comparison | Cetrorelix (Cetrotide) Cetrotide | Degarelix (Firmagon) Firmagon |
|---|---|---|
| How it works | How it works Cetrorelix does the same job as leuprolide by the opposite route, and in fertility that difference is the whole point. | How it works Degarelix exists because the flare that leuprolide causes is a genuine clinical problem in some patients. |
| What it is | A GnRH antagonist used in IVF to stop an egg being released too early. | A GnRH antagonist for prostate cancer, and the one with no testosterone flare. |
| Status | FDA approvedFDA-approved | FDA approvedFDA-approved |
| Typical dose | — | — |
| How often | Daily during an IVF cycle | Loading dose, then monthly |
| Stays active | About 5 hours at 0.25 mg, about 63 hours at 3 mg | About 53 days |
| Dose comes from | FDA drug label | FDA drug label |
| Cycled? | Set by the prescription FDA drug label | Set by the prescription FDA drug label |
| What it does | ||
| Drug class | GnRH antagonist | GnRH antagonist |
| Used for | A prescription drug used during fertility treatment to prevent premature ovulation. | A prescription drug for advanced prostate cancer, giving immediate testosterone suppression. |
| Receptors hit | — | — |
| Numbers | ||
| Full dose line | Set by the label | Set by the label |
| Why that cycle | This is a prescription drug. Duration and schedule are set by the label and the prescriber, not by a cycling convention. | This is a prescription drug. Duration and schedule are set by the label and the prescriber, not by a cycling convention. |
| Weight / effect | Not measured in a trial | Not measured in a trial |
| Chain length | Not disclosed | Not disclosed |
| Common vial | — | — |
| Before you start | ||
| Route | Under the skin (subcutaneous) | Under the skin (subcutaneous) |
| Do not use if | Pregnancy or breastfeeding Known hypersensitivity to GnRH analogues or to mannitol Severe kidney impairment Use outside a supervised fertility protocol | Known hypersensitivity to degarelix or any component Pregnancy, which does not apply to its approved population but matters for handling Use outside a prescription, where no label governs the dose |
What separates them
Staying on it. Degarelix is taken continuously. Cetrorelix is normally run in blocks with breaks, though for this one the block length is convention rather than a tested schedule.
What doesn't differ: They are both taken the same way (under the skin). Neither has a measured effect size from a published trial, so there is no number to rank them on.
What people actually report
Cetrorelix (Cetrotide)
- Used within a supervised fertility treatment cycle.
- Ovarian hyperstimulation syndrome is a risk of the stimulation protocol it is used within.
- Severe abdominal pain, bloating or rapid weight gain, which can signal ovarian hyperstimulation syndrome
- Signs of an allergic reaction, including facial or throat swelling or trouble breathing
Degarelix (Firmagon)
- Profound testosterone suppression is the intended effect and drives most side effects.
- Injection site reactions are common and can be marked.
- Signs of an allergic reaction, including facial or throat swelling or trouble breathing
- Severe or spreading injection site reaction
Side effects are what users and trials report most often, not a complete list. Anything sudden, spreading, or breathing-related is an emergency regardless of which compound caused it.
People also compare
This comparison does not cover cost, long-term safety, or how you personally will respond. Effect figures come from separate trials in different populations and are not always directly comparable to each other. Nothing here is medical advice or a recommendation to use any of these. Talk to a clinician about your own situation.