Gonadorelin: the basics
What is it?
A lab-made copy of GnRH, a 10-amino-acid hormone from the brain that tells the pituitary gland to release LH and FSH, the hormones that control ovaries and testes.
Research paper 1 ↗Research paper 2 ↗Research paper 3 ↗Research paper 4 ↗What do people claim it helps with?
Help with fertility problems, restarting periods, and raising testosterone in men. Good evidence exists only for specific fertility uses, and none is an FDA-approved U.S. use today.
What has research actually shown?
When given in pulses that copy the body's natural rhythm, it reliably restores ovulation in women whose brain signal is switched off (hypothalamic amenorrhea). Results in polycystic ovary syndrome are unclear.
Research paper 1 ↗Research paper 2 ↗Research paper 3 ↗Research paper 4 ↗Has this been demonstrated in people?
Many human studies over decades, including randomized trials and a 35-study meta-analysis in women. Studies in men are smaller and mostly observational.
Research paper 1 ↗Research paper 2 ↗Research paper 3 ↗Research paper 4 ↗What side effects, risks and unknowns should I understand?
Twins or more happen slightly more often than in the general population, and ovarian over-stimulation is uncommon and usually mild. This comes mostly from carefully monitored fertility care.
Research paper ↗Is it an approved medicine?
Not as a currently sold human medicine. FDA approved Factrel in 1982 and Lutrepulse in 1989, but both are listed as discontinued. Gonadorelin is still FDA-approved for use in cattle.
FDA safety information 1 ↗FDA safety information 2 ↗Prescribing information 3 ↗Approval here means U.S. FDA approval and applies to a particular product, formulation and use. This is a starting overview, not a complete side-effect list. Sources checked 10 October 2026; independent scientific review pending.
How is it used or studied?
Was given as an injection or through a small pump that delivers pulses under the skin or into a vein. Today's U.S. human products, if offered, are compounded.
Different routes and formulations can have different effects. A study of one product does not validate every product with the same peptide name.
A common misunderstanding
Pulses mimic the body's signal and switch the system on; constant exposure to GnRH-like drugs (such as leuprolide) does the opposite and shuts it down.
What should I ask a clinician?
- What diagnosis or goal are we trying to address, and what established options are available?
- Was the expected benefit shown in people like me, using this exact product?
- How could my medicines, health conditions or pregnancy plans affect the risks?
- What monitoring is needed, and what would tell us the treatment is helping or should be stopped?
What do the research words mean?
- Peptide
- A short chain of amino acids, the building blocks of proteins.
- Preclinical
- Research in cells, tissues or animals before dependable treatment evidence in people.
- Controlled trial
- A study comparing a treatment with another treatment or a placebo to help separate its effects from other explanations.
- Biomarker
- A measurement, such as a hormone level. A change does not necessarily mean someone feels better or lives longer.
Gonadorelin Evidence & Clinical Profile
Human Study Limits
Gonadorelin has been investigated in clinical contexts. Patient outcomes must be evaluated against study size, design, and control cohorts.
Laboratory & In Vivo Assays
Cellular and animal disease models examine receptor binding affinities and signaling cascades, which require human confirmation.
What is Gonadorelin?
Gonadorelin (synthetic GnRH) is Gonadorelin is a synthetic copy of gonadotropin-releasing hormone (GnRH), the 10-amino-acid brain hormone that tells the pituitary to release LH and FSH. FDA approved human gonadorelin products as Factrel (1982) and Lutrepulse (1989), but both are now listed as discontinued. Pulsatile GnRH therapy has solid evidence for restoring ovulation in hypothalamic amenorrhea. Gonadorelin remains FDA-approved for cattle. Aliases include: GnRH, LHRH, Gonadotropin-releasing hormone, Factrel, Lutrepulse, Lutrelef.
- Sequence (one-letter)
- pEHWSYGLRPG-NH2
- Molecular formula
- C55H75N17O13
- Molecular weight
- 1182.3 g/mol
- CAS Number
- 33515-09-2
- UNII Code
- 9O7312W37G
- PubChem CID
- 638793
Identifiers checked against PubChem and FDA's Global Substance Registration System on 13 October 2026. FDA substance record ↗ · PubChem record ↗ See all names and codes in the peptide name index.
Clinical Trials & Human Cohorts
Human research can examine tolerability, symptoms or patient outcomes. The design and comparator determine what each result can establish.
Efficacy and safety of pulsatile GnRH therapy in idiopathic and functional hypothalamic amenorrhea: meta-analysis [2]
What was reported
Pulsatile GnRH gave high ovulation rates, mostly single pregnancies, and rare, mild ovarian hyperstimulation.
What limits the conclusion
32 of the 35 studies were observational, so rates come mostly from uncontrolled series.
Pulsatile GnRH vs combined gonadotropins for ovulation induction in hypothalamic amenorrhea with PCOS [3]
What was reported
Ovarian response was similar, but clinical pregnancy was more common with pulsatile GnRH (46% vs 0%).
What limits the conclusion
Small single-center trial in a narrow subgroup.
Pulsatile GnRH and earlier spermatogenesis vs gonadotropins in congenital hypogonadotropic hypogonadism [4]
What was reported
Sperm appeared sooner with pulsatile GnRH than with hCG/HMG (median 6 vs 18 months).
What limits the conclusion
Not randomized, only 20 men in the GnRH group, and different follow-up times; testosterone was lower in the GnRH group.
Pulsatile GnRH for ovulation induction in subfertility associated with PCOS [5]
What was reported
Trials were too small and short to prove or rule out a benefit of pulsatile GnRH in polycystic ovary syndrome.
What limits the conclusion
Each of the four trials tested a different comparison.
How the compound may work
Mechanisms describe how Gonadorelin may affect biological processes. Laboratory findings and patient outcomes answer different questions.
Pituitary GnRH receptor stimulation
Gonadorelin has the same sequence as natural GnRH. Given in pulses, it stimulates the pituitary to release LH and FSH, which drive ovulation and sperm production. [2]
Native sequence identified
The decapeptide sequence of LH- and FSH-releasing hormone was reported in 1971 from porcine hypothalami; gonadorelin is the synthetic version. [1]
Areas Being Studied
These research topics reflect active areas of scientific exploration, distinct from unverified commercial marketing claims.
Female infertility
Ovulation induction in hypothalamic amenorrhea; limited, inconclusive data in PCOS. [2]
Male hypogonadotropic hypogonadism
Inducing sperm production as an alternative to gonadotropin injections. [4]
Down syndrome cognition
A randomized placebo-controlled trial of pulsatile GnRH; no results posted. [13]
Compare the study designs.
| Study | Design / sample | Outcome type | Key limitation |
|---|---|---|---|
| Hypothalamic amenorrhea · 2018 [2] | Systematic review & meta-analysis n = 1002 |
Clinical endpoint evaluation | 32 of the 35 studies were observational, so rates come mostly from uncontrolled series. |
| HA with PCOS · 2013 [3] | Single-center randomized trial n = 30 |
Clinical endpoint evaluation | Small single-center trial in a narrow subgroup. |
| Male CHH fertility · 2017 [4] | Retrospective cohort study n = 202 |
Clinical endpoint evaluation | Not randomized, only 20 men in the GnRH group, and different follow-up times; testosterone was lower in the GnRH group. |
| PCOS (Cochrane) · 2004 [5] | Cochrane systematic review n = 57 |
Clinical endpoint evaluation | Each of the four trials tested a different comparison. |
Regulatory Status & Clinical Safety
Regulatory Classification
Human products Factrel (NDA 018123) and Lutrepulse (NDA 019687) are listed as discontinued in Drugs@FDA. Gonadorelin acetate is in FDA's 503B category 1 (under evaluation). Approved veterinary products exist. WADA S2 prohibited in males.
Safety Realities & Impurities
Safety depends on the molecule, formulation, route and evidence. A laboratory purity measurement alone cannot establish safety for human use.
Clinical Trials Registry Records
Official registry records from ClinicalTrials.gov. Study registration does not imply government endorsement or guaranteed efficacy.
LutrePulse Hypogonadotropic Hypogonadism [11]
- Planned enrollment
- 39 (patients)
- Posted results
- Available
- Sponsor
- Ferring Pharmaceuticals
- Last updated
- 2021
A Multicenter, Randomized, Double-Blind, Placebo-Controlled Study to Assess the Efficacy and Safety of Three Dosage Strengths of Pulsatile GnRH [12]
- Planned enrollment
- 132 (patients)
- Posted results
- Pending in registry
- Sponsor
- Ferring Pharmaceuticals
- Last updated
- 2011
GnRH Therapy on Cognition in Down Syndrome [13]
- Planned enrollment
- 56 (patients)
- Posted results
- Pending in registry
- Sponsor
- Nelly Pitteloud
- Last updated
- 2024
A Study to Measure Pharmacokinetic (PK) Concentrations of Gonadotropin-Releasing Hormone Delivered by the OmniPod Pump [14]
- Planned enrollment
- 0 (patients)
- Posted results
- Pending in registry
- Sponsor
- Ferring Pharmaceuticals
- Last updated
- 2025
WADA & Anti-Doping Regulations
WADA Section S2: Prohibited Substance
The World Anti-Doping Agency (WADA) classifies Gonadorelin under Section S2 of the Prohibited List. Prohibited at all times (in- and out-of-competition). Last verified: October 2026.
Research Timeline
-
1971
Structure reported
Schally's group reports the amino acid sequence of the LH- and FSH-releasing hormone. [1]
-
1982
Factrel approved
FDA approves Factrel (gonadorelin hydrochloride) injection, a new molecular entity. Drugs@FDA now lists it as discontinued. [6]
-
1989
Lutrepulse approved
FDA approves the Lutrepulse kit (gonadorelin acetate). Drugs@FDA now lists it as discontinued. [7]
-
2025
Development stopped
Ferring withdraws a planned Lutrepulse pump study, citing business reasons unrelated to safety or efficacy. [14]
-
2025
Compounding status
Gonadorelin acetate sits in FDA's 503B category 1 (under evaluation), marked as a component of an FDA-approved drug. [8]
-
2026
Veterinary use
Gonadorelin injections remain FDA-approved for cattle, including Factrel (NADA 139-237). [9]
-
2026
Banned in male athletes
WADA's 2026 list prohibits GnRH (gonadorelin) and its agonist analogues in males under S2. [10]
What Researchers Still Don't Know
Long-term safety profiles
Multi-year observational data in broader heterogeneous cohorts remains uncharacterized.
Optimal dose-response thresholds
Comparative trials optimizing minimal effective exposure versus adverse event rates.
Formulation bioavailability
Differences between oral, subcutaneous, and modified peptide delivery vehicles.
References
Primary sources verified against PubMed / NLM and regulatory databases.
- Structure determination
- Systematic review & meta-analysis
- Randomized controlled trial
- Retrospective cohort study
- Cochrane systematic review
- FDA Drugs@FDA record
-
FDA Drugs@FDA record
Drugs@FDA: LUTREPULSE KIT (gonadorelin acetate), NDA 019687 (discontinued) ↗ (external website)
- FDA compounding list
-
Veterinary drug label
FACTREL (gonadorelin hydrochloride) injection, for use in cattle (NADA 139-237) ↗ (external website)
-
Anti-doping rule
World Anti-Doping Code International Standard: Prohibited List 2026 ↗ (external website)
-
Registry Record
LutrePulse Hypogonadotropic Hypogonadism ↗ (external website)
- Registry Record
-
Registry Record
GnRH Therapy on Cognition in Down Syndrome ↗ (external website)
- Registry Record