Compound record · Sexual health

Gonadorelin

Also GnRH · LHRH · Gonadotropin-releasing hormone · Factrel · HRF

Gonadotropin-releasing hormone (GnRH) decapeptide

Sexual healthEvidence · ModerateApproved medicine (for specific indications)WADA · Prohibited at all times

Native GnRH: a licensed pituitary test and pump therapy, compounded off-label with testosterone

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Record reviewed 26 September 2026 · 10 references

In the AERVYN range

1 pen carries Gonadorelin

Single-compound pen
Gonadorelin
Peptide pen · 10 mg / 3 mL
£200 · In stock

Class: Synthetic native GnRH (10 amino acids)
Licensed uses: Pituitary function test (UK: HRF); pulsatile pump for amenorrhoea and hypogonadotropic hypogonadism (some countries)
Half-life: About 4 minutes — pulses stimulate, continuous exposure suppresses
Use with testosterone: Compounded in the US; no controlled trials
Anti-doping: Prohibited at all times in males (WADA S2.2.1)

01 Overview

What Gonadorelin is

Summary

Gonadorelin is the synthetic form of gonadotropin-releasing hormone (GnRH), the ten-amino-acid hypothalamic hormone that drives the pituitary to release luteinising hormone (LH) and follicle-stimulating hormone (FSH). It has been a licensed medicine for decades — as a single 100 mcg injection to test pituitary gonadotroph function (still authorised in the UK as HRF) and, delivered in pulses every 60–120 minutes by a portable pump, to restore ovulation in hypothalamic amenorrhoea and fertility in hypogonadotropic hypogonadism. The pump products have been withdrawn from the US and Canadian markets for commercial reasons. Its plasma half-life is about four minutes, so how it is given matters: pulses stimulate the axis, whereas continuous or long-acting exposure shuts it down. In the US it is widely compounded and prescribed alongside testosterone therapy to keep the testes signalling — a use supported by physiology and small observational series rather than controlled trials.

Mechanism

Binds GnRH receptors on pituitary gonadotrophs and triggers release of LH and FSH, which in turn drive testicular testosterone production and spermatogenesis, or ovarian follicle development and oestradiol. Because the receptor desensitises under constant stimulation, only intermittent (pulsatile) exposure maintains gonadotropin output; sustained exposure — the basis of GnRH-agonist treatment for prostate cancer and endometriosis — suppresses the axis. Gonadorelin is cleared within minutes, so a single injection produces a short LH surge and pump therapy has to deliver a pulse roughly every 90 minutes.

Routes studiedSubcutaneous injection, Intravenous, Intranasal

Anti-dopingProhibited at all times

02 Evidence by goal

What has been shown, for which goal

Grades follow one scale across the site. Moderate overall means: at least one well-conducted randomised trial or consistent controlled human studies.

Sexual health
Limited
Strong evidence exists for pulsatile GnRH in specific diagnoses — a 25-year cohort of 66 women with hypothalamic amenorrhoea achieved a 65.9% live-birth rate per treatment, and a meta-analysis of 420 men with congenital hypogonadotropic hypogonadism found spermatogenesis induced sooner than with gonadotropins. The use most often marketed — injections alongside testosterone therapy to preserve testicular size, fertility or libido — rests on physiology, hCG data and small uncontrolled series; no randomised trial of gonadorelin for this purpose has been published, and it does not treat erectile dysfunction or low desire directly.
General wellbeing
Insufficient
Any effect on energy, mood or wellbeing would be indirect, through restored gonadotropin and sex-steroid output in someone whose axis is suppressed or deficient. No trial has measured wellbeing outcomes with gonadorelin, and in people with a normal axis there is no reason to expect a benefit.
Longevity
Insufficient
Marketed as 'hormone optimisation' for ageing men. There are no human data linking gonadorelin to healthspan, body composition or any ageing outcome, and the age-related fall in testosterone is mostly testicular rather than hypothalamic, which limits what a GnRH signal can restore.

03 Regulatory status

Where it is authorised, and for what

Status is recorded per jurisdiction from regulator sources and reviewed by hand. It is never inferred from another region's decision.

United Kingdom

Authorised

Authorised (MHRA) as a 100 mcg diagnostic injection (HRF); prescription-only. Not licensed for any treatment use.

Gonadorelin 100 micrograms powder for solution for injection (HRF 100 microgram; PL 17509/0005, Esteve Pharmaceuticals) is licensed as a single subcutaneous or intravenous injection to evaluate the response of the pituitary gonadotrophs, and is listed on the eMC with an SmPC revised in August 2022. No UK product is licensed for pulsatile-pump therapy or for use alongside testosterone; such use would be off-label or with an unlicensed import, and gonadorelin sold online as a 'research peptide' is an unlicensed medicine.

StatusAuthorised

Status last reviewed26 September 2026

SourceOur maintained database — never inferred

04 Dosing research

What the evidence says about exposure

Published human studies and the doses, routes and durations they used — reported as research information, not a recommendation.

Research information — not a recommendation. These are the exposures used in published human studies, reported so you can see what has been tested. They are not dosing instructions and do not apply to any individual.

Study 01

Pulsatile subcutaneous GnRH for ovulation induction in functional hypothalamic amenorrhoea — 25-year single-centre cohort

Quaas P et al., J Assist Reprod Genet 2022;39:2729–2736 · Source

Observational2022

Design: Retrospective cohort (1996–2020) with a matched control group for birth weight
Population: Infertile women with functional hypothalamic amenorrhoea
Participants: n = 66
Duration: 212 ovulation-induction cycles across 82 treatments
Route: Subcutaneous injection

Doses studied: 10 mcg gonadorelin (Lutrelef) subcutaneously every 90 minutes by portable pump
Outcome at this exposure: Ovulation in 96% of cycles, monofollicular in 75%; live-birth rate 65.9% per treatment; cumulative clinical pregnancy rate 74.4%; one twin pregnancy (1.6%); newborn birth weight comparable to controls.
Adverse events observed: Miscarriage rate 11.5%; no ovarian hyperstimulation syndrome reported; local pump-site problems were not systematically recorded.

Study 02

Pulsatile GnRH pump in adult men with congenital hypogonadotropic hypogonadism — medium-term outcomes

Jiang H et al., Transl Androl Urol 2025;14:2043–2058 · Source

Observational2025

Design: Retrospective single-centre cohort with 6-, 12- and 24-month assessments
Population: Adult men with congenital hypogonadotropic hypogonadism
Participants: n = 54
Duration: Mean follow-up 15.9 months (range 3–40)
Route: Subcutaneous injection

Doses studied: Gonadorelin acetate 10 mcg per pulse every 90 minutes subcutaneously (16 pulses/24 h), increased in 5 mcg steps according to LH, FSH and testosterone; a single 100 mcg intravenous dose was used for the baseline stimulation test
Outcome at this exposure: Mean testicular volume rose from 3.2 mL to 9.7 mL and serum testosterone from 48 to 381 ng/dL at two years, with further gains between 6 and 24 months. Of the men treated for more than six months, 27 (79.4%) produced sperm, first appearing after about six months on average.
Adverse events observed: No infusion-related complications reported; the study was retrospective and not designed to capture adverse events systematically.

Every controlled or cohort study of gonadorelin uses one of two regimens: a single 100 mcg injection as a diagnostic test, or micro-pulses of 5–20 mcg every 60–120 minutes from a programmable pump. The compounded regimens marketed with testosterone therapy — typically 100–200 mcg injected once or twice a day, or several times a week — have no published trial behind them and are not pulsatile in the physiological sense; with a four-minute half-life each injection produces a brief LH surge rather than sustained signalling, and the dose–response for testicular preservation has never been established.

05 Safety

Adverse effects and contraindications

Common effects seen in trials or reports, serious effects that warrant urgent review, and conditions under which use is not appropriate or needs assessment.

Common adverse effects

Injection- or pump-site pain, redness, itching or induration
Headache
Nausea and abdominal discomfort
Flushing, light-headedness or a fast heartbeat (rare in the licensed diagnostic use)
Transient rise in LH, FSH and sex steroids — oestradiol-related effects (breast tenderness, mood change) in some men
Acne or oily skin with rising testosterone

Serious adverse effects

Allergic and anaphylactoid reactions (reported with both the diagnostic test and pump therapy; more frequent than with gonadotropins in the male CHH meta-analysis)
Multiple pregnancy and ovarian hyperstimulation during ovulation induction (low with pulsatile GnRH, but not zero)
Paradoxical suppression of the axis if exposure is continuous or too frequent — the opposite of the intended effect
Stimulation of a hormone-sensitive tumour (theoretical)
Antibody formation against the peptide with repeated exposure (rare in the licence)
Infection, abscess or sepsis from a pump or injection site, particularly with non-sterile compounded products (sepsis is listed in the UK licence with unknown frequency)

Contraindications

Hormonal disorderCaution
Gonadorelin only works if the pituitary can respond: it is ineffective in primary (testicular or ovarian) failure and in pituitary disease, and pointless where the axis is intact. Pituitary tumours, hyperprolactinaemia, PCOS and any unexplained hormonal disorder need specialist assessment first, and any use with testosterone therapy should be supervised by the prescriber managing that therapy.
CancerCaution
Stimulating LH, FSH and sex-steroid output is a theoretical concern in hormone-sensitive cancers — prostate, breast, ovarian and endometrial — where the standard treatment is to suppress exactly this axis. A current or previous hormone-sensitive cancer needs oncology input before any GnRH stimulation.

Do not use = should not be used · Caution = needs assessment

06 Interactions

Medicine classes that need review

Grouped by how seriously the combination should be taken. Class labels match the medicines questionnaire in the assessment.

Major
Moderate
Minor

Moderate

Monitoring or dose review is usually advised.

Testosterone / anabolic hormone
Testosterone gel or injection
Exogenous testosterone suppresses hypothalamic GnRH and pituitary LH/FSH; gonadorelin is prescribed alongside it precisely to counter that. The combination has no controlled trial data, changes the testosterone and oestradiol levels the prescriber is monitoring, and should only be run under the supervision of whoever manages the testosterone.
Hormone replacement therapy
Oestrogen, progesterone
Oestrogen and progestogen feed back on the pituitary and blunt the gonadotropin response, so gonadorelin's effect — and the diagnostic test result — is altered; combined use has no evidential basis outside fertility clinics.

Minor

Generally compatible; awareness is sufficient.

Oral contraceptive
Combined pill, progestogen-only pill
Hormonal contraception suppresses the gonadotropin response and defeats the purpose of pulsatile GnRH; the diagnostic test is not interpretable on the pill. No safety interaction, but no rationale for combining them either.

07 Pregnancy & breastfeeding

Status in pregnancy

Contraindicated

The UK licence lists known or suspected pregnancy as a contraindication and states that gonadorelin should not be given to pregnant women or nursing mothers; pump therapy for ovulation induction is stopped as soon as pregnancy is confirmed. There is no reason to use gonadorelin in pregnancy or while breastfeeding.

08 Monitoring

What is usually monitored

Parameters that trials and product information track. A clinician decides what applies to an individual.

01LH, FSH and total testosterone (or oestradiol and follicle tracking in women), before starting and during use — the response is the only evidence it is working
02Semen analysis or testicular volume if fertility or testicular size is the goal
03Oestradiol and haematocrit when combined with testosterone therapy
04Pump or injection sites for reactions and infection
05Prostate symptoms and PSA in men over 40, as with any testosterone-raising treatment
06Anti-doping status: prohibited at all times for male athletes (WADA S2.2.1)

09 Combinations

What is known about combining it

Notes on pairing with other compounds in the directory: whether the combination has been studied in people, and where mechanisms overlap.

PT-141 (bremelanotide)
No human studies
Overlap · Both are sold for sexual health, but gonadorelin acts on the hormonal axis while PT-141 acts on brain melanocortin receptors.
No study has combined them. They address different problems — hormonal signalling versus desire — and there is no rationale or safety data for using both.
Tesamorelin
No human studies
Overlap · Both are hypothalamic releasing-hormone analogues (GnRH and GHRH) acting on different pituitary cells.
Marketed together in 'hormone optimisation' protocols. No human data on the combination; each stimulates a separate pituitary axis and there is no reason to expect one to help the other.
Semaglutide
No human studies
No human data on the combination. Weight loss with a GLP-1 medicine can itself raise testosterone in men with obesity, which complicates interpreting any gonadorelin effect.

Discuss any proposed combination with a qualified healthcare professional.

10 Source considerations

Supply, quality and legitimacy

How the compound reaches people in practice, and what that means for product quality.

01Licensed gonadorelin exists — the UK diagnostic injection and national pump products in parts of Europe — but only as prescription medicines for specific indications; nothing sold for use alongside testosterone is an authorised product.
02US compounded gonadorelin is legal to compound and comes from state-licensed 503A pharmacies or 503B outsourcing facilities; it is not FDA-approved and quality varies with the compounder.
03'Research' vials and pens sold online fall outside every medicines quality system; identity, content and sterility rest on the vendor's certificate.
04The licensed product is a powder that is reconstituted immediately before use and discarded after 24 hours; a pre-filled aqueous pen relies on the manufacturer's own stability data, which should be requested.
05Veterinary gonadorelin (for cattle) is the same molecule but is formulated and tested for animals; it is not a legitimate human supply.

11 Questions for your clinician

Take these to your appointment

Specific to this compound. The personal assessment adds questions drawn from your own history and medicines.

01Is my hypothalamic–pituitary axis actually suppressed or deficient, and has that been shown with blood tests rather than assumed?
02If I am on testosterone therapy and want to preserve fertility or testicular size, how do gonadorelin, hCG and a break from testosterone compare in evidence and in what you have seen in practice?
03How will you check that it is working — which hormones, how often — and what result would make us stop?
04Do I have any hormone-sensitive condition, or a family history of prostate or breast cancer, that makes stimulating this axis a concern?
05If I compete in tested sport, do you understand that gonadorelin is prohibited at all times for men?

The personal assessment tailors this list to your responses.

12 References

Sources behind this record

Regulator documents and peer-reviewed publications used to derive every grade and statement above.

The Peptide Checkup provides educational information and a structured summary of published research and regulatory status. It is not medical advice, does not diagnose or treat any condition, and does not replace a consultation with a qualified healthcare professional.

Personal assessment

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Seven minutes of structured questions about your goal, history and medicines, mapped against this record by a deterministic, clinician-reviewable rules engine. The report tells you when not to buy.

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