Scientific context only. Not medical advice, not a recommendation to use.
At a glance
Gonadorelin is the synthetic decapeptide with an amino-acid sequence identical to endogenous gonadotropin-releasing hormone (GnRH/LHRH). Historically approved in several countries for diagnostic testing of pituitary function and for fertility indications (pump systems). A defining feature is the opposite effect of pulsatile versus continuous administration: pulsatile stimulates, continuous leads to receptor desensitisation.
Researched for
Diagnostic testing of the hypothalamic-pituitary-gonadal axis (GnRH stimulation test)Ovulation induction in hypothalamic amenorrhea (pump)Spermatogenesis induction in congenital hypogonadotropic hypogonadism (pump)Differentiating hypothalamic from pituitary dysfunction
Official status
US: Prescription
The original human gonadorelin product (Factrel, NDA 017866) and the pump product Lutrepulse/Lutrelef were approved as prescription products in the US but have been withdrawn for commercial reasons; currently no human gonadorelin finished medicinal product is commercially available. A same-named veterinary product (Factrel, Zoetis) remains approved for use in cattle. Prescription-only.
Gonadorelin acts as an agonist at the GnRH receptor on the gonadotroph cells of the pituitary and triggers release of the gonadotropins luteinizing hormone (LH) and follicle-stimulating hormone (FSH). The temporal pattern of receptor exposure is decisive: pulsatile administration mimics the natural hypothalamic secretory rhythm and sustains LH/FSH release, whereas continuous exposure leads to receptor internalisation and desensitisation with subsequent paradoxical suppression of gonadotropins. The latter principle is exploited therapeutically by longer-acting GnRH agonists.
02
Evidence at a glance
Reading note. The distribution shows on which evidence tier each observation sits. Strong colours mark stronger evidence — weaker tiers are deliberately visible, not hidden.
4 observations · single evidence tier
Human trial
4
03
What the studies show
Human trial
Mensch
Zhang L, Cai K, Wang Y, Ji W, Cheng Z, Chen G, Liao Z 2019
Pulsatile delivery via a pump system induced spermatogenesis in men with congenital hypogonadotropic hypogonadism, earlier than under cyclical gonadotropin therapy in a comparative study
What does NOT follow: Small sample size, retrospective design; the overall success rate did not differ significantly between groups. No usage recommendation.
Human trial
Mensch
Hurley DM, Brian R, Outch K, Stockdale J, Fry A, Hackman C, Clarke I, Burger HG 1984
Pulsatile low-dose administration restored ovulation in women with functional hypothalamic amenorrhea and resulted in pregnancies
What does NOT follow: Efficacy limited to suprapituitary (hypothalamic) causes; not effective in pituitary dysfunction. No usage recommendation.
Human trial
Mensch
Büchter D, Behre HM, Kliesch S, Nieschlag E 1998
Both pulsatile GnRH and a combined gonadotropin therapy induced spermatogenesis with subsequent pregnancies in men with hypogonadotropic hypogonadism
What does NOT follow: Retrospective case series without randomisation; results between the treatment modalities not statistically significantly different. No usage recommendation.
Human trial
Mensch
The Medical Letter on Drugs and Therapeutics 1990
A single administration triggers measurable LH and FSH release, which forms the basis of the diagnostic GnRH stimulation test to assess pituitary reserve
What does NOT follow: Diagnostic context; the original human product is no longer available in several markets. No usage recommendation.
04
Where studies disagree
Open question
Does gonadorelin reliably maintain testicular function during exogenous testosterone therapy?
POSITION A
Gonadorelin is widely used off-label to maintain testicular function during testosterone therapy, since it theoretically stimulates the entire pituitary-gonadal signalling cascade upstream of the gonadotropins.
POSITION B
High-quality controlled evidence specifically for this off-label use is lacking; the robust pulsatile-GnRH evidence derives mostly from hypogonadotropic-hypogonadism populations, not from exogenously suppressed axes.
CURRENT STATE · The evidence for this specific off-label use is limited and not supported by randomised trials. No usage recommendation.
05
Pharmacokinetics
Theoretical concentration curve at a half-life of 0.1 h. Pure pharmacokinetic model — not a dosing recommendation.
Which routes of administration the available studies describe — neutral reporting, not a usage guide.
Subcutaneous
In the fertility literature predominantly administered subcutaneously via portable pump systems in a pulsatile pattern.
Intravenous
In the diagnostic GnRH stimulation test the substance was used as a single intravenous dose.
06d
Safer use & risks
Risk notes for harm reduction — descriptive, not a usage or dosing guide.
⚠ Important — please read
This platform does NOT provide usage or dosing instructions. The points below describe risks and are meant to help avoid harm — they do not replace medical advice. Anyone who uses a substance should discuss it with a doctor.
This substance is approved (in at least one country) — use belongs in medical hands, within the approved indication and a physician-set dose.
Online numbers are not a benchmark
Amounts from TikTok, YouTube and forums are mostly imitation rather than data — and are often wrongly derived from animal studies (µg/kg). Not a reliable benchmark for humans.
Sterility & infection risk
Injection solutions prepared or stored non-sterile carry an infection and abscess risk. Contamination is common with grey-market product.
Unknown product quality
Research-/grey-market product is not quality-tested: identity, purity and actual content are often unknown, and counterfeits occur.
Mind interactions
Combinations with medications or pre-existing conditions can carry risks (see the Interactions section). Clarify with a doctor beforehand.
Warning signs — seek medical help
With persistent pain, redness/swelling at the injection site, fever, shortness of breath, racing heart, chest pain or allergic reactions, seek medical help immediately.
A doctor, not a forum
Concrete questions about use and amount belong in a conversation with a doctor — not in a comment thread.
07
Known adverse events from studies
Factual reporting of what studies observed. Not a safety statement for individual use.
Human trial
Local reactions at the administration site
Reported in the documented studies using pump systems; frequency figures vary by study.
in der Literatur berichtet
Human trial
Multiple pregnancies with ovulation induction
In the pulsatile GnRH literature a comparatively low rate is reported versus direct gonadotropin stimulation; depends on patient population and protocol.
niedrig in der pulsatilen Literatur
07b
Interactions & combinations
Documented interactions and contraindications from studies, prescribing information and guidelines. Where no data exists, this is stated.
Reporting of risks, NOT a combination guide. The absence of an entry does not mean „safe to combine“ but „not sufficiently studied“.
No documented interactions recorded
We have not yet found robustly documented interactions for this peptide. This does NOT mean none exist — the data is limited.
11
Legal status by country
Country
Status
Note
Checked
United States
Prescription
The original human gonadorelin product (Factrel, NDA 017866) and the pump product Lutrepulse/Lutrelef were approved as prescription products in the US but have been withdrawn for commercial reasons; currently no human gonadorelin finished medicinal product is commercially available. A same-named veterinary product (Factrel, Zoetis) remains approved for use in cattle. Prescription-only.
2026-06-07
Germany
Prescription
Gonadorelin was listed in Germany as a prescription medicine for the diagnostic GnRH test and fertility indications. Availability and products have changed over the years; the substance is prescription-only and not an over-the-counter product.
2026-06-07
12
Reconstitution calculator
Pure mg/mL maths — works like a calculator. Not a usage recommendation.
Peptides ship as a dry powder. Once dissolved in a liquid (reconstitution), this calculator answers a single question: how much substance is in one millilitre of solution afterwards?
1Enter the vial's substance amount (printed on the label).
2Enter how much solvent you add.
3Result = concentration in mg per mL.
Printed on the label
/
Liquid you add
=
2.50
mg / mL
5 mg in 2 mL gives 2.50 mg/mL — each millilitre contains 2.50 mg of substance.
Büchter D, Behre HM, Kliesch S, Nieschlag E · 1998
Pulsatile GnRH or human chorionic gonadotropin/human menopausal gonadotropin as effective treatment for men with hypogonadotropic hypogonadism: a review of 42 cases