Skip to main content

How long does it take for Degarelix to work?

Medically reviewed by Carmen Pope, BPharm. Last updated on Oct 30, 2023.

Official answer


Degarelix works almost immediately, with an initial injection of degarelix causing a drop in testosterone levels of 88% after 1 day. Within 3 days, levels had dropped by 94%, and by 28 days, 98%. When given every 28 days, levels of testosterone remain at least 98% below normal.

The initial dose of degarelix is 240 mg (given as two subcutaneous injections of 120 mg) and the maintenance dose is 80mg given once every 28 days. When given using this dosage regimen, degarelix is effective in achieving and maintaining testosterone suppression below the castration level of 50 ng/dL.

Degarelix works by binding to pituitary GnRH receptors, reducing the release of luteinizing hormone (LH) and follicle-stimulating hormone (FSH), and subsequently testosterone. It may be used for the treatment of advanced prostate cancer and also for medical castration. Degarelix belongs to the class of medicines known as GnRH receptor antagonists.

  • Degarelix Updated 10/2021 AHFS Monograph
  • Firmagon (degarelix acetate) Updated 03/2020. Ferring Pharmaceuticals Inc.
  • Firmagon (degarelix acetate)

Read next

Related medical questions

Drug information

Related support groups