Leuprolide vs Degarelix
Written by Aaron CuhaReviewed Sep 2026
The short answer
A drug that first switches on the GnRH signal, against one that blocks it, for the same job. The first causes a testosterone surge in the first days of treatment and the second does not. That difference was measured directly in the trial that got degarelix approved.
- Leuprolide people
- 199
- Leuprolide nulls
- 0
- Degarelix people
- 610
- Degarelix nulls
- 0
Dose
Approved medicine. No human dose established for unlabelled uses
Labeled amounts sit on the prescribing information. This page records what trials measured, not a personal dose.
FDA-approved (Lupron)
Dose
Approved medicine. No human dose established for unlabelled uses
Labeled amounts sit on the prescribing information. This page records what trials measured, not a personal dose.
FDA-approved on 24 December 2008 under NDA 022201, sold as Firmagon, to treat advanced prostate cancer. No boxed warning. Not approved for any use beyond that, including prostate cancer that has not spread, any use in women, or any use in healthy adults.
First-hand reports are counted on each profile and never added together. This page sets two published records side by side. It does not pick a winner.
Column A
LeuprolideLeuprolide (GnRH agonist)
A prescription medicine, not a research peptide. It has been used since the 1980s and is FDA-approved as Lupron for prostate cancer, endometriosis, fibroids and puberty that starts too early.
Column B
DegarelixDegarelix (Firmagon), GnRH receptor antagonist
A hormone blocker approved in 2008 for advanced prostate cancer. In its main study of 610 men, testosterone was down to castration level by day 3 in about 96 percent on degarelix, and in none on the older drug, leuprolide. Over 12 months it held testosterone down just as well. 40 percent had reactions where the shot went in, against under 1 percent on leuprolide. The study built to test whether it is easier on the heart was stopped early and found no difference.
These two were tested against each other in the same trial
One trial gave people each of them. This is not us lining up two separate records.
The main goal was met by 97.2 percent, 98.3 percent and 96.4 percent of the degarelix 240/80, degarelix 240/160 and leuprolide groups. So degarelix counted as no worse. By day 3, testosterone was at or below 0.5 ng per mL in about 96 percent of degarelix patients and in none of the leuprolide patients. The middle PSA at days 14 and 28 was clearly lower on degarelix. Reactions at the shot site hit 40 percent on degarelix under the skin, against under 1 percent on leuprolide into the muscle, a clear gap.
What the trial was
A large final stage trial lasting 12 months. Everyone knew which drug they got. 610 men with prostate cancer of any stage, with a middle age of 72, a middle testosterone of 3.93 ng per mL and a middle PSA of 19.0 ng per mL. There were three plans. Two used degarelix 240 mg as a shot under the skin in month one, then 80 mg or 160 mg monthly. The third used leuprolide 7.5 mg as a monthly shot into the muscle. The main goal was testosterone at or below 0.5 ng per mL at every monthly check from day 28 to day 364.
What the authors concluded
The authors conclude that degarelix was no worse than leuprolide at keeping testosterone low over 12 months. It pushed testosterone and PSA down clearly faster. And it removes the need for extra drugs to cover the surge that can make symptoms flare.
Where this result is weak
Everyone knew which drug they got, it ran 12 months, and the main measure is a hormone level, not survival or symptoms. How fast testosterone drops matters in a small group, men at risk of a flare, and this trial was not built to show a survival difference in anyone. The rate of shot site reactions is the trade off, and it is large. A later trial built to test whether degarelix is safer for the heart was stopped early and found no difference.
Klotz and colleagues, 12 month phase III (CS21), BJU International, 2008
Side by side, on the facts we can check
| What we compare | Leuprolide | Degarelix |
|---|---|---|
| Category | Hormone | Hormone |
| FDA status | FDA-approved (Lupron) | FDA-approved on 24 December 2008 under NDA 022201, sold as Firmagon, to treat advanced prostate cancer. No boxed warning. Not approved for any use beyond that, including prostate cancer that has not spread, any use in women, or any use in healthy adults. |
| Half-life | ~3 hours (depot lasts months) | About 53 days terminal, driven by slow release from the subcutaneous depot. |
| Molecular weight | 1,209.4 Da | About 1632 Da as the free base, per the label. A decapeptide with five D-amino acids. |
| How it works | A steady signal on the GnRH receptor wears out the pituitary gland's response. That sharply lowers LH, FSH and the sex hormones they control. | It blocks the GnRH receptor in the pituitary gland directly. That stops the hormones that drive the testes right away, so testosterone falls within days with no first surge. This is the opposite of how leuprolide, goserelin and triptorelin work. Those drugs get their effect by first overworking the same receptor. Degarelix also forms a little store under the skin where it was injected, and seeps out slowly. That explains both why it lasts so long in the body and why so many people react at the shot site. |
| Studies in people | 2 | 3 |
| Evidence | Moderate: 2 completed trials, 199 people given it | Moderate: 2 completed trials, 610 people given it |
| Legal status, US | FDA-approved, prescription only | FDA-approved, prescription only |
Frequently asked questions
What is the difference between Leuprolide and Degarelix?
Leuprolide: A prescription medicine, not a research peptide. It has been used since the 1980s and is FDA-approved as Lupron for prostate cancer, endometriosis, fibroids and puberty that starts too early. Degarelix: A hormone blocker approved in 2008 for advanced prostate cancer. In its main study of 610 men, testosterone was down to castration level by day 3 in about 96 percent on degarelix, and in none on the older drug, leuprolide. Over 12 months it held testosterone down just as well. 40 percent had reactions where the shot went in, against under 1 percent on leuprolide. The study built to test whether it is easier on the heart was stopped early and found no difference.
Which has stronger research evidence, Leuprolide or Degarelix?
Each compound gets a band worked out from facts we counted, with the math shown. Leuprolide is Moderate (2 completed trials, 199 people given it). Degarelix is Moderate (2 completed trials, 610 people given it). That counts how much has been done in people. It does not rate whether either one works, and neither one is called the winner.
Are Leuprolide and Degarelix FDA-approved?
Leuprolide: FDA-approved (Lupron). Degarelix: FDA-approved on 24 December 2008 under NDA 022201, sold as Firmagon, to treat advanced prostate cancer. No boxed warning. Not approved for any use beyond that, including prostate cancer that has not spread, any use in women, or any use in healthy adults..
Reviewed Sep 2026. This page puts two published records side by side. It is for learning, and it is not medical advice. When this site shows a dose, it is the dose a trial or a clinic actually used, or what people say they did, with the source attached. None of it tells you what to take.