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Hormones & TRT
Cancer & Diagnostics
Clinical

Degarelix

Also known as: Firmagon, FE 200486

A GnRH antagonist injection for advanced prostate cancer that lowers testosterone within days without a flare. FDA-approved as Firmagon (2008).

Last updated

Mechanism of Action

Degarelix is a synthetic decapeptide that binds and blocks GnRH receptors in the pituitary. Because it is an antagonist rather than an agonist, it suppresses LH and FSH immediately, without the initial testosterone surge seen with leuprolide or goserelin; most men reach castrate testosterone levels within 3 days. After subcutaneous injection it forms a gel depot that releases drug slowly, allowing monthly maintenance dosing.

Half-life
~53 days (maintenance dose, depot release)
Administration Routes
Subcutaneous
Research Status
Clinical

Reported Benefits

  • Treatment of advanced prostate cancer (androgen deprivation)
  • Rapid testosterone suppression without a tumor flare
  • Faster PSA reduction than leuprolide in the pivotal trial

Potential Side Effects

  • Injection-site reactions (pain, redness, swelling), very common
  • Hot flashes, weight gain and fatigue
  • Increased liver transaminases
  • QT prolongation with androgen deprivation therapy
  • Loss of bone density with long-term use

Common Dosing

The labeled regimen is a starting dose given as two subcutaneous abdominal injections, followed by a monthly maintenance injection beginning 28 days later. Injections are given by a healthcare provider. Dosing is set and supervised by the prescribing clinician.

The dosing information above is aggregated from research literature and anecdotal community reports for educational purposes only. It is not a recommendation, prescription, or medical advice. Peptides are sold as research chemicals only and are not intended for human use.

Contraindications

  • Known hypersensitivity to degarelix or any component
  • Not indicated for women; can cause fetal harm

No documented stacking partners for Degarelix yet.

  • The efficacy and safety of degarelix: a 12-month, comparative, randomized, open-label, parallel-group phase III study in patients with prostate cancer

    2008

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  • Cardiovascular Safety of Degarelix Versus Leuprolide in Patients With Prostate Cancer: The Primary Results of the PRONOUNCE Randomized Trial

    2021

    View

  • Degarelix for treating advanced hormone-sensitive prostate cancer

    2021

    View

Yes. Degarelix was approved by FDA in December 2008 as Firmagon (Ferring) for advanced prostate cancer. As of 2026 both the 120 mg and 80 mg vials are listed by FDA as prescription products.

That was the question behind the PRONOUNCE trial, which compared degarelix with leuprolide in men with prostate cancer and heart disease. The trial ended early with too few events and found no significant difference in major cardiovascular events.

GnRH agonists stimulate the pituitary before they shut it down, which briefly raises testosterone. Degarelix blocks the receptor from the start, so testosterone falls within days without that initial rise.

PeptideChat is for educational and research purposes only. Nothing on this site constitutes medical advice. Peptides are sold as research chemicals only and are not intended for human use. These statements have not been evaluated by the FDA and are not intended to diagnose, treat, cure, or prevent any disease. PeptideChat is an independent educational resource — not a pharmacy, compounding, or 503A/503B outsourcing facility — and does not sell products or provide medical advice.