Gonadorelin: what it is, what the studies show and where it stands
Gonadorelin is synthetic gonadotropin-releasing hormone (GnRH), which makes the pituitary release LH and, less strongly, FSH. The one human product whose label could be opened, Lutrepulse, gives it as a small pulse every 90 minutes from a wearable pump to induce ovulation.
At a glance
US No longer sold
Canada No longer sold
Group Hormonal and sexual health
Sources 13
Checked 10 Oct 2026What is Gonadorelin?
Gonadorelin is synthetic gonadotropin-releasing hormone (GnRH), which makes the pituitary release LH and, less strongly, FSH. The one human product whose label could be opened, Lutrepulse, gives it as a small pulse every 90 minutes from a wearable pump to induce ovulation. [1]
Other names: GnRH, gonadotropin-releasing hormone, LHRH, gonadorelin acetate, gonadorelin hydrochloride, Lutrepulse, Factrel.
How it has been given to people: subcutaneous or intravenous pulses from a pump (treatment); single intravenous or subcutaneous injection (pituitary stimulation test).
Looking for doses? Gonadorelin dosage chart and vial math
Is Gonadorelin approved in the US and Canada?
United States: No FDA-approved human gonadorelin product is marketed in the US. Drugs@FDA lists both approved products, Factrel (NDA 018123, approved 1982-09-30) and Lutrepulse Kit (NDA 019687, approved 1989-10-10), as Discontinued. [2]
Canada: No authorized human gonadorelin product is being sold in Canada. The Drug Product Database lists Lutrepulse 3.2 mg/vial (DIN 02046202) as Dormant since 2017-04-21 and every other human gonadorelin product as Cancelled Post Market. [3]
Both were checked on 10 Oct 2026 against the regulators' own product databases.
Which approved products contain Gonadorelin?
What human studies of Gonadorelin exist?
The 7 findings listed here: 7 from smaller or observational human studies.
An older 2-year comparison in men found no advantage for pulsed subcutaneous GnRH over hCG/hMG. [7]
In 22 patients assessed for precocious puberty, a single subcutaneous 100 mcg test gave LH results that matched the standard intravenous test. [9]
In the monograph's pivotal studies, 94% (45 of 48) of women with primary hypothalamic amenorrhea ovulated on pulsed gonadorelin. [1]
In the same studies, 58% (25 of 43) of the women with primary hypothalamic amenorrhea who wanted a pregnancy became pregnant. [1]
In men with congenital hypogonadotropic hypogonadism, sperm first appeared after a median 6 months on the pulsatile pump against 18 months on hCG/hMG injections (retrospective cohort, 20 against 182 men). [5]
In a nonrandomized study, sperm production started in 90% of men on the gonadorelin pump and 83.3% on cyclical hCG/hMG, at a median of 6 and 14 months. [6]
As a one-off 100 mcg test in 104 patients with pituitary region disease, the response did not help clinical assessment. [8]
What are the side effects of Gonadorelin?
Reported in human studies or on a label:
- Side effects were reported in about 10% of treatment courses in the pivotal trials, mostly at the injection or pump site. [1]
- Pump-related: inflammation, infection, mild vein irritation or bruising at the catheter site. [1]
- Multiple pregnancy: 12% of the pregnancies with delivery information were multiple. [1]
- Ovarian hyperstimulation was rare: one moderate case among 268 women, in a cycle that also used clomiphene. [1]
- Severe allergic reaction (anaphylaxis) has been reported with gonadorelin hydrochloride (Factrel). [1]
- Antibodies formed in about 3% of patients given Factrel under the skin, in some cases with reduced effect. [1]
- In men on the pump, a hardened red allergic skin reaction at the infusion site was common in one study. [6]
Warnings on the label
- Contraindicated in women with any condition that pregnancy could make worse, such as a pituitary prolactinoma. [1]
- Contraindicated with ovarian cysts. [1]
- Contraindicated in any condition that reproductive hormones could make worse, such as a hormone-dependent tumor. [1]
- Serious warning: ovarian hyperstimulation syndrome is a known risk of ovulation induction, though rare with pulsed GnRH. [1]
- To be run by physicians experienced in pulsatile GnRH delivery, with ultrasound monitoring. [1]
- Steady, non-pulsed exposure can temporarily blunt the pituitary's response. [1]
- Interaction: not to be combined with other ovulation-stimulating medicines. [1]
- Kidney failure, but not liver disease, prolongs the half-life. [1]
What is the half-life of Gonadorelin?
Very short. After intravenous or subcutaneous injection, blood levels fall with an initial half-life of 2 to 10 minutes and a terminal half-life of 10 to 40 minutes. [1]
How does Gonadorelin compare with others in its group?
These are the peptides filed under hormonal and sexual health. The last column says whether a randomized human trial is on record for each.
| Peptide | US | Canada | Half-life | Randomized human trial |
|---|---|---|---|---|
| PT-141 (bremelanotide) | Approved for one use | Not authorized | About 2.7 hours after a single subcutaneous dose (the label gives a range of 1.9 to 4.0 hours). Blood levels peak at about 1 hour. | Yes |
| Kisspeptin-10 | Not approved | Not authorized | Not found | Yes |
| Gonadorelin | No longer sold | No longer sold | Very short. After intravenous or subcutaneous injection, blood levels fall with an initial half-life of 2 to 10 minutes and a terminal half-life of 10 to 40 minutes. | No |
| Testagen | Not approved | Not authorized | Not found | No |
| HCG | Approved, prescription | Authorized, prescription | About 32 to 33 hours after a single injection of 5,000 or 10,000 IU in 18 healthy women, the same by muscle or under the skin. | Yes |
| HMG | Approved, prescription | Authorized, prescription | FSH from Menopur had an elimination half-life of 11 to 13 hours after repeated doses, by injection under the skin or into a muscle. The label gives no half-life for the LH part. | Yes |
What could not be found
These were searched for and did not turn up. They are listed so a missing number is not mistaken for a hidden one.
- US human labels for Factrel and Lutrepulse: not in openFDA or DailyMed. No Factrel label dose is given here; the 100 mcg test rows come from published studies.
- Why the human products were discontinued: no FDA or Health Canada statement was found.
- No human trial of gonadorelin given as occasional injections (for example twice a week) was found, including for keeping the testes working during testosterone therapy.
- Whether gonadorelin can be compounded under section 503A was not determined. It does not appear on FDA's category list of nominated bulk substances updated May 14, 2026.
- Labels for the cancelled Canadian products (Factrel, Relisorm) were not opened.
- Numbers of men, doses and schedules are missing from several pump-study abstracts; rows above use only what the abstract or open full text states.
Gonadorelin questions
Is Gonadorelin approved in the US?
No FDA-approved human gonadorelin product is marketed in the US. Drugs@FDA lists both approved products, Factrel (NDA 018123, approved 1982-09-30) and Lutrepulse Kit (NDA 019687, approved 1989-10-10), as Discontinued.
Is Gonadorelin authorized in Canada?
No authorized human gonadorelin product is being sold in Canada. The Drug Product Database lists Lutrepulse 3.2 mg/vial (DIN 02046202) as Dormant since 2017-04-21 and every other human gonadorelin product as Cancelled Post Market.
What is the half-life of Gonadorelin?
Very short. After intravenous or subcutaneous injection, blood levels fall with an initial half-life of 2 to 10 minutes and a terminal half-life of 10 to 40 minutes.
Has Gonadorelin been tested in a randomized human trial?
No randomized human trial was found. What exists is listed under the studies heading on this page.
Sources
Each one was opened on 10 Oct 2026 and matched to the line it supports.
- Ferring Inc. PRODUCT MONOGRAPH LUTREPULSE Gonadorelin Acetate for Injection 3.2 mg/vial 2016. pdf.hres.ca.
- US Food and Drug Administration Drugs@FDA (openFDA drugsfda endpoint): applications with gonadorelin as active ingredient 2026. api.fda.gov.
- Health Canada Drug Product Database (API): active ingredient lookup for GONADORELIN, with product and status records 2026. health-products.canada.ca.
- Health Canada Drug Product Database API documentation: Product Status definitions 2026. health-products.canada.ca.
- Mao JF et al. Pulsatile gonadotropin-releasing hormone therapy is associated with earlier spermatogenesis compared to combined gonadotropin therapy in patients with congenital hypogonadotropic hypogonadism. Asian J Androl 2017. PubMed 28051040.
- Zhang L et al. The Pulsatile Gonadorelin Pump Induces Earlier Spermatogenesis Than Cyclical Gonadotropin Therapy in Congenital Hypogonadotropic Hypogonadism Men. Am J Mens Health 2019. PubMed 30569789.
- Liu L et al. Two-year comparison of testicular responses to pulsatile gonadotropin-releasing hormone and exogenous gonadotropins from the inception of therapy in men with isolated hypogonadotropic hypogonadism. J Clin Endocrinol Metab 1988. PubMed 3142911.
- Chammas NK et al. The GnRH test in the assessment of patients with pituitary and parapituitary lesions: results of a 5-year retrospective study. Pituitary 2008. PubMed 18425583.
- Eckert KL et al. A single-sample, subcutaneous gonadotropin-releasing hormone test for central precocious puberty. Pediatrics 1996. PubMed 8632938.
- Zoetis Inc. FACTREL (GONADORELIN HYDROCHLORIDE) INJECTION [ZOETIS INC.] 2026. dailymed.nlm.nih.gov.
- Health Canada Unauthorized injectable peptide drugs seized and sold by Canada Peptide may pose serious health risks 2025. recalls-rappels.canada.ca.
- World Anti-Doping Agency World Anti-Doping Code International Standard Prohibited List 2026 2026. wada-ama.org.
- Cretu AM et al. Emerging peptide and neuroendocrine strategies for TRT-induced reproductive suppression and functional male hypogonadism: a narrative review. Front Reprod Health 2026. PubMed 42666625.
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