PeptidePeptideGnRHReproductive pharmaceutical

Gonadorelin

Also known as GnRH · LHRH · Factrel · Lutrelef

Written by enwyReviewed 15 Jul 20261 sources0 comments

Gonadorelin is synthetic gonadotropin-releasing hormone (GnRH), an approved pharmaceutical. Given in pulses it stimulates pituitary release of LH and FSH; it has been used diagnostically to test pituitary function and therapeutically (via pump) for hypothalamic infertility. In hormone-replacement circles it is used to maintain testicular function, though hCG is more commonly chosen for that role.

01 Overview

Gonadorelin is identical to endogenous GnRH, the decapeptide that drives pituitary gonadotropin secretion. Because the axis responds to pulsatile rather than continuous GnRH, its clinical use reflects this: pulsatile pump administration can restore fertility in hypothalamic hypogonadism, while a single dose is used to assess pituitary responsiveness. This is a genuinely approved, well-characterised drug.

In testosterone-replacement and post-cycle contexts it is used off-label to keep the testes stimulated. Its extremely short half-life means bolus subcutaneous dosing produces only brief LH/FSH pulses, and continuous exposure paradoxically suppresses the axis (the basis for GnRH-agonist therapies), so dosing schedule matters greatly.

02 Mechanism

Acts as GnRH at pituitary gonadotroph receptors; pulsatile administration stimulates LH and FSH release, whereas continuous or high-dose exposure downregulates receptors and suppresses gonadotropins.

03 Dosing

Tier	Dose	Route	Notes
Off-label HPTA support	100–200 mcg	SubQ	Off-label bolus dosing, often 2-3 times weekly or daily; pulsatile pump protocols differ. Diagnostic dose ~100 mcg.

04 Effects

Effect	Magnitude	Evidence
Stimulates LH and FSH releasePulsatile administration reliably triggers pituitary LH/FSH secretion.	Reproducible gonadotropin pulse	Clinical
Maintains testicular function (off-label)Used to preserve testicular size/function on TRT, though hCG is better established for this.	Variable	Observational

05 Side effects

Effect	Severity	Frequency	Evidence	Countermeasures
Injection-site and hypersensitivity reactionsLocal reactions and rare hypersensitivity have been reported with clinical use.	Mild	Occasional	Clinical
Axis suppression with continuous dosingNon-pulsatile or excessive dosing downregulates the axis and suppresses gonadotropins.	Moderate	Schedule-dependent	Clinical

06 Legal status

United States

FDA-approved prescription drug

Approved (e.g. diagnostic and pulsatile fertility use); off-label HPTA support is common. · as of Jan 2026

07 References

Gonadorelin (GnRH) clinical pharmacology and pulsatile therapyEndocrinology reference / drug label

08 Discussion0 comments

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This page is reference information, not medical advice. Doses and protocols are documented as they appear in the clinical literature and in practice — describing them is not a recommendation to use them. Countermeasures listed here are not a substitute for a physician. Legal status varies by jurisdiction and changes.