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Gonadorelin

Decapeptide hypothalamic releasing hormone

Also known as GnRH, LHRH, Luteinizing hormone-releasing hormone, Factrel

The native GnRH decapeptide. An established diagnostic and fertility agent whose popular use, restarting suppressed testosterone production, is the use with the least evidence behind it.

What doses have been studied? What each trial gave, with the population it was given to.

Guide updated Oct 22, 2026Literature checked Oct 21, 20262 curated studies63 literature recordsBaseline editorial
SequenceQHWSYGLRPG

Overview

In shortA synthetic copy of the hormone that tells the pituitary to release the reproductive hormones. It has a long history in fertility medicine and as a diagnostic test. It is here mostly for a use it was never developed for: restarting the body's own hormone production after it has been suppressed by taking steroids. That use is common in practice and thin in the literature, and both facts matter.

Gonadorelin is synthetic gonadotropin-releasing hormone, identical to the hypothalamic decapeptide that drives the pituitary to release LH and FSH. It has a long clinical history in fertility medicine and as a diagnostic agent for pituitary function.

Its presence in this compendium is mostly about a use it was not developed for: restarting the hypothalamic-pituitary-gonadal axis after suppression from exogenous androgens. That application is common in practice and thin in the literature, and the two facts are worth holding together.

Mechanism

In shortIt triggers release of the reproductive hormones from the pituitary, but only if given in pulses. Continuous stimulation does the opposite: it shuts the receptor down and suppresses those hormones, which is exactly how chemical castration drugs work. The same molecule stimulates or suppresses depending on how it is given, which is the most important thing to know about it.

Binds the GnRH receptor on pituitary gonadotrophs, triggering LH and FSH release. The critical detail is that the response depends on pulsatile delivery. Continuous or frequent stimulation downregulates the receptor and suppresses gonadotropin release instead, which is precisely how GnRH agonists like leuprolide achieve chemical castration.

The same molecule therefore stimulates or suppresses depending entirely on how it is given. Very few compounds in this compendium have a mechanism that reverses this cleanly with dosing pattern, and it is the single most important thing to understand about it.

Evidence

In shortEstablished as a diagnostic test of pituitary function, and historically in pump therapy for a specific hormone deficiency. For restarting the system after steroid use the evidence is close to absent: no controlled trials compare it against the alternatives, and its very short life in the body makes the commonly described dosing patterns questionable.

Established for diagnostic use in evaluating pituitary gonadotropin reserve, and historically in pulsatile pump therapy for hypogonadotropic hypogonadism, where the evidence is good.

For post-cycle axis recovery, the evidence is close to absent. There is no body of controlled trials comparing gonadorelin against hCG, clomiphene or no treatment for that purpose, and its very short half-life makes the dosing patterns commonly described mechanistically questionable.

Safety

In shortWell tolerated at the diagnostic doses it was approved at, with headache, nausea and injection site reactions commonly reported. The mechanical risk is the one above: a schedule that accidentally produces continuous rather than pulsed stimulation will suppress the very system it was meant to restart. That is a foreseeable failure mode, not a freak reaction.

Well tolerated in the diagnostic doses it was approved at. Headache, nausea and injection site reactions are the common reports.

The mechanistic risk is the one described above: a regimen that inadvertently produces continuous rather than pulsatile stimulation can suppress the axis it was meant to restart. That is a foreseeable failure mode of the compound rather than an idiosyncratic reaction.

Regulatory status

In shortApproval status varies a lot and several branded versions have been discontinued in major markets, so approved is often true historically and false at the pharmacy counter today. Widely available through compounding pharmacies in some countries and as research material elsewhere. Banned in sport for male athletes.

Approval status varies considerably and several branded formulations have been discontinued in major markets, which means "approved" is often true historically and false at the pharmacy counter today.

Widely available through compounding pharmacies in some jurisdictions and as research-use-only material elsewhere. Prohibited in sport: WADA lists GnRH and its analogs in the S2 category for male athletes.

The literature

2 studies indexed. Findings and limitations get equal weight, on purpose.

Always check the primary source

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Everything above is free to read. What an account opens is the evidence underneath it: 2 studies with their limitations, and the regimen each trial actually reported.

  • Every study, with what it found and what it cannot show
  • The limitations, given the same weight as the findings
  • The dose each named trial administered, where recorded
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The wider literature

32 indexed papers and 31 registered trials mentioning Gonadorelin, straight from PubMed and ClinicalTrials.gov. 15 of 31 administer it; the rest measure it. These have not been read by us. Unlike the studies above, they carry no findings and no limitations written by anyone here, because writing either would mean claiming a reading nobody has done. They are a starting point for yours.

Registered trials (31)

  1. Comparison of the Euploid Rate of Blastocyst Between PPOS and GnRH Antagonist Protocol in Women With PCOS Undergoing PGT-A

    ShangHai Ji Ai Genetics & IVF Institute2026NCT05326087

    interventionalphase3not yet recruitingn=204

  2. A Non-interventional Study for Kisqali (Ribociclib) in Combination With an Aromatase Inhibitor for Adjuvant Treatment in Patients With HR+/HER2- Early Breast Cancer at High Risk of Recurrence

    Novartis Pharmaceuticals2025NCT06830720

    observationalrecruitingn=3250

  3. Sexual Coercion in Breast Cancer Patients Treated With Luteinizing Hormone-Releasing Hormone Agonists (LHRHa )

    Canan Kas2024NCT06840847

    interventionalnacompletedn=79

  4. Evaluate the Effectiveness of Progestin-Primed Versus GnRH Antagonist Protocols in Vietnamese Women Undergoing In-vitro Fertilization

    Hanoi Medical University2023NCT06191809

    interventionalnaunknownn=200

  5. Controlled Ovarian Stimulation Versus Modified Natural Cycles in Poor Responders

    University Hospital, Ghent2022NCT04487925

    interventionalphase4unknownn=208

  6. Teverelix Evaluated in Advanced Prostate Cancer

    Antev Ltd.2021NCT04693507

    interventionalphase2completedn=50

  7. A Study Evaluating the Efficacy and Safety of Giredestrant Compared With Physician's Choice of Endocrine Monotherapy in Participants With Previously Treated Estrogen Receptor-Positive, HER2-Negative Locally Advanced or Metastatic Breast Cancer (acelERA Breast Cancer)

    Hoffmann-La Roche2020NCT04576455

    interventionalphase2active not recruitingn=303

  8. Luteal Phase Support With Daily Administration of Gonadotropin-releasing Hormone Agonist Compared to Progesterone/Estradiol in IVF/ICSI Cycles With Ovulation Triggering With GnRH-a

    Kuban State Medical University2020NCT05143723

    interventionalphase2unknownn=102

  9. Effect of GnRH Agonist vs GnRH Antagonist on IVF/ICSI Outcomes in Polycystic Ovary Syndrome Patients.

    Damascus University2019NCT04727671

    interventionalphase4completedn=50

  10. Radium Ra 223 Dichloride, Hormone Therapy and Stereotactic Body Radiation Therapy in Treating Patients With Metastatic Prostate Cancer

    City of Hope Medical Center2018NCT03361735

    interventionalphase2active not recruitingn=25

  11. A Trial to Investigate the Efficacy and Safety of FE 999302 as add-on Treatment to Follitropin Delta (REKOVELLE) in Women Undergoing Controlled Ovarian Stimulation.

    Ferring Pharmaceuticals2018NCT03564509

    interventionalphase2completedn=620

  12. To Investigate the Cumulative Live Birth Rates Using GnRH Antagonist or Agonist Protocol for COS in ART Treatment

    Peking University Third Hospital2018NCT04026282

    interventionalnaunknownn=888

  13. Remifemin Preventing the Climacteric Symptoms in Breast Cancer

    Zhejiang Cancer Hospital2017NCT03339882

    interventionalphase2completedn=85

  14. Hormonal Mechanisms of Sleep Restriction - Axis Study

    Peter y. Liu2017NCT03142893

    interventionalphase1active not recruitingn=80

  15. The Four Methods of Ovarian Stimulation in Patients With Polycystic Ovarian Syndrome

    Royan Institute2016NCT03876145

    interventionalnacompletedn=120

  16. Real-life Evaluation of the Effect of ADT in Prostate Cancer Patients in Asia (READT Asia Study)

    Chinese University of Hong Kong2016NCT03703778

    observationalactive not recruitingn=300

  17. MENOPUR® in a Gonadotropin-Releasing Hormone (GnRH) Antagonist Cycle With Single-Blastocyst Transfer in a High Responder Subject Population

    Ferring Pharmaceuticals2015NCT02554279

    interventionalphase4completedn=620

  18. Efficacy and Safety of Medication Used to Stimulate Ovulation

    Create Fertility Center2015NCT02715336

    interventionalphase4unknownn=666

  19. Luteal Antagonist Versus Conventional Treatment in Women With Severe Early Ovarian Hyperstimulation Syndrome (OHSS)

    Eugonia2015NCT02392520

    interventionalnaunknownn=40

  20. Fairly Brief Androgen Suppression and Stereotactic Radiotherapy for High Risk Prostate Cancer - Protocol 2

    London Health Sciences Centre Research Institute OR Lawson Research Institute of St. Joseph's2014NCT02229734

    interventionalphase2completedn=60

  21. Evaluation of Priming Before in Vitro Maturation for Fertility Preservation in Breast Cancer Patients

    Hôpital Jean Verdier2014NCT03954197

    interventionalnaunknownn=204

  22. GnRH Agonist as Luteal Support in FET Cycles

    Turku University Hospital2013NCT02620124

    interventionalphase4completedn=100

  23. Dual Trigger to Reduce Ovarian Hyperstimulation Syndrome

    Chenshiling2012NCT02022228

    interventionalnaunknownn=200

  24. Degarelix in the Treatment of Endometriosis Recurrence

    Centre for Endocrinology and Reproductive Medicine, Italy2012NCT01712763

    interventionalphase3completedn=360

  25. Cabazitaxel With Radiation and Hormone Therapy for Prostate Cancer

    Sidney Kimmel Comprehensive Cancer Center at Thomas Jefferson University2011NCT01420250

    interventionalphase1completedn=20

  26. Randomized Crossover Trial to Assess the Tolerability of Gonadotropin Releasing Hormone (GnRH) Analogue Administration

    Watson Pharmaceuticals2010NCT01161563

    interventionalphase4completedn=118

  27. A 4 Year Combination Therapy of Growth Hormone and (GnRH) Agonist in Children With a Short Predicted Height

    Belgian Study Group for Pediatric Endocrinology2008NCT00840944

    interventionalphase4unknownn=44

  28. Determining How Quickly Progesterone Slows LH Pulse Frequency

    University of Virginia2007NCT00594217

    interventionalphase1completedn=85

  29. Prospective Observation Study of Insulin Sensitivity During and After Gonadotropin Releasing Hormone Agonist Therapy for Prostate Cancer

    Massachusetts General Hospital2006NCT00456144

    observationalcompletedn=36

  30. Rapid Hormonal Cycling as Treatment for Patients With Prostate Cancer: The Men's Cycle

    Memorial Sloan Kettering Cancer Center2001NCT00586898

    interventionalphase2completedn=36

  31. Follicle Stimulating Hormone (FSH) to Improve Testicular Development in Men With Hypogonadism

    Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)2001NCT00064987

    interventionalphase2terminatedn=19

Papers (32)

  1. Relugolix in treatment of prostate cancer: a review.

    Kyriazis I, et al.Archivio italiano di urologia, andrologia : organo ufficiale [di] Societa italiana di ecografia urologica e nefrologica2025PMID 41247145

    journal articlereview

  2. Luteinizing Hormone-Releasing Hormone (LHRH)-Targeted Treatment in Ovarian Cancer.

    Nayak P, et al.International journal of molecular sciences2025PMID 41465311

    journal articlereview

  3. Andrew Victor Schally: Pioneering Neuroendocrinologist and Architect of Luteinizing Hormone-Releasing Hormone Analogs.

    Grujić M, et al.Cureus2024PMID 39398731

    journal articlereview

  4. The safety of neoadjuvant hormonal treatment in infants with cryptorchidism.

    Fiala V, et al.Journal of pediatric urology2022PMID 35691791

    journal articlerandomized controlled trial

  5. Transcriptomic evidence of luteinizing hormone-releasing hormone agonist (LHRH-A) regulation on lipid metabolism in grass carp (Ctenopharyngodon idella).

    Zhong H, et al.Genomics2021PMID 32971214

    journal articleresearch support, non-u.s. gov't

  6. The Role of Gonadotropin-Releasing Hormone (GnRH) in Endometrial Cancer.

    Emons G, et al.Cells2021PMID 33535622

    journal articlesystematic review

  7. Pituitary response to GnRH stimulation tests in different FSHB-211 G/T genotypes.

    Sansone A, et al.Human reproduction (Oxford, England)2021PMID 33704441

    journal articleresearch support, non-u.s. gov't

  8. Gonadotropin-Releasing Hormone and GnRH Receptor: Structure, Function and Drug Development.

    Tzoupis H, et al.Current medicinal chemistry2020PMID 31309882

    journal articlereview

  9. Investigational luteinizing hormone releasing hormone (LHRH) agonists and other hormonal agents in early stage clinical trials for prostate cancer.

    Singla N, et al.Expert opinion on investigational drugs2019PMID 30649971

    journal articlereview

  10. Zn(2+)-triggered self-assembly of Gonadorelin [6-D-Phe] to produce nanostructures and fibrils.

    Yordanova Y, et al.Scientific reports2018PMID 30050082

    journal articleresearch support, non-u.s. gov't

  11. Recent Development of Non-Peptide GnRH Antagonists.

    Tukun FL, et al.Molecules (Basel, Switzerland)2017PMID 29232843

    journal articlereview

  12. Degarelix versus luteinizing hormone-releasing hormone agonists for the treatment of prostate cancer.

    Clinton TN, et al.Expert opinion on pharmacotherapy2017PMID 28480768

    journal articlereview

  13. Optimizing subcutaneous injection of the gonadotropin-releasing hormone receptor antagonist degarelix.

    Barkin J, et al.The Canadian journal of urology2016PMID 26892063

    journal article

  14. Impact of BMI on gonadorelin-stimulated LH peak in premenarcheal girls with idiopathic central precocious puberty.

    Fu JF, et al.Obesity (Silver Spring, Md.)2015PMID 25645648

    journal articleresearch support, non-u.s. gov't

  15. Receptors for luteinizing hormone-releasing hormone (GnRH) as therapeutic targets in triple negative breast cancers (TNBC).

    Kwok CW, et al.Targeted oncology2015PMID 25293576

    journal articleresearch support, non-u.s. gov't

  16. Luteinizing hormone-releasing hormone receptor targeted agents for prostate cancer.

    Liu SV, et al.Expert opinion on investigational drugs2011PMID 21449823

    journal articlereview

  17. Luteinizing hormone-releasing hormone receptor-mediated delivery of mitoxantrone using LHRH analogs modified with PEGylated liposomes.

    He Y, et al.International journal of nanomedicine2010PMID 20957221

    journal articleresearch support, non-u.s. gov't

  18. Luteinizing hormone-releasing hormone (LHRH) agonists in the treatment of breast cancer.

    Hackshaw AExpert opinion on pharmacotherapy2009PMID 19874248

    journal articlereview

  19. Non-peptidic GnRH receptor antagonists.

    Armer RE, et al.Current medicinal chemistry2004PMID 15544487

    journal articlereview

  20. The neuroendocrinology of human puberty revisited.

    Grumbach MMHormone research2002PMID 12065920

    journal articlereview

  21. Development of luteinizing hormone releasing hormone neurones.

    Wray SJournal of neuroendocrinology2001PMID 11123510

    journal articlereview

  22. Melatonin inhibits luteinizing hormone releasing hormone (LHRH) induction of LH release from fetal rat pituitary cells.

    Hattori A, et al.Neuroscience letters1995PMID 7724042

    journal article

  23. Luteinizing hormone-releasing hormone (LHRH)-expressing cells do not migrate normally in an inherited hypogonadal (Kallmann) syndrome.

    Schwanzel-Fukuda M, et al.Brain research. Molecular brain research1989PMID 2687610

    journal articleresearch support, non-u.s. gov'tresearch support, u.s. gov't, p.h.s.

  24. Luteinizing hormone-releasing hormone (LHRH) agonists for treatment of advanced prostatic carcinoma.

    Chodak GWUrology1989PMID 2523610

    clinical trialjournal articlereview

  25. The role of gonadotropin releasing hormone (Gn-RH) in the regulation of gonadal functions of birds. Review article.

    Péczely PActa biologica Hungarica1989PMID 2699145

    journal articlereview

  26. Neuroendocrinology of the pituitary gland.

    Reichlin SToxicologic pathology1989PMID 2675278

    journal articlereview

  27. Origin of luteinizing hormone-releasing hormone neurons.

    Schwanzel-Fukuda M, et al.Nature1989PMID 2645530

    journal articleresearch support, non-u.s. gov'tresearch support, u.s. gov't, p.h.s.

  28. Luteinizing hormone releasing hormone (LHRH) neuroterminals mapped using the push-pull perfusion method in the rhesus monkey.

    Gearing M, et al.Brain research bulletin1988PMID 3064879

    journal articleresearch support, u.s. gov't, p.h.s.

  29. Luteinizing hormone-releasing hormone (LH-RH) binding to purified rat pituitary nuclei.

    Millar RP, et al.FEBS letters1983PMID 6311621

    journal articleresearch support, non-u.s. gov't

  30. Gonadorelin--synthetic LH-RH.

    The Medical letter on drugs and therapeutics1983PMID 6358816

    journal article

  31. Human placental receptors for luteinizing hormone releasing hormone.

    Currie AJ, et al.Biochemical and biophysical research communications1981PMID 6263276

    journal article

  32. Distribution of luteinizing hormone-releasing hormone (LHRH) in the guinea pig brain.

    Silverman AJEndocrinology1976PMID 780101

    journal articleresearch support, u.s. gov't, p.h.s.

Discussion

Gonadorelin has its own forum, and sits in Testosterone & Hormones. Every post says what kind of claim it makes.

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For Research & Educational Discussion Only. Not Medical Advice

This guide is educational reference material compiled from published literature. It is not medical advice, not a recommendation, and not a substitute for a clinician who knows your history. Nothing here should be used to make a decision about your own health without one.

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