Gonadorelin (GnRH)
Also known as: GnRH, Gonadotropin-Releasing Hormone, LHRH, Factrel
Overview
Gonadorelin is the synthetic form of naturally occurring gonadotropin-releasing hormone (GnRH/LHRH), a decapeptide produced by hypothalamic neurons and released in a pulsatile fashion to stimulate pituitary LH and FSH secretion. When administered in a physiologically pulsatile pattern, gonadorelin restores normal gonadotropin secretion in hypothalamic hypogonadism. Used diagnostically to assess pituitary LH/FSH reserve and therapeutically in pulsatile pump delivery for hypothalamic amenorrhea and male infertility. Continuous administration (like GnRH agonists) causes receptor downregulation.
Mechanism of Action
Gonadorelin binds GnRH receptor (GnRHR), a Gq/11-coupled GPCR on pituitary gonadotroph cells. Pulsatile GnRH activates phospholipase C, generating IP3-mediated calcium release and PKC activation, which stimulates synthesis and release of both LH and FSH. The pulsatile pattern is critical: the GnRHR requires episodic stimulation (approximately every 60-90 minutes for optimal LH/FSH release in females; every 90-180 minutes in males). Continuous exposure causes receptor internalization and downregulation—the mechanism exploited by GnRH agonists like leuprolide for medical castration.
Potential Benefits
- Restoration of physiological LH/FSH secretion in hypothalamic hypogonadism
- Diagnostic test for pituitary gonadotroph reserve
- Treatment of hypothalamic amenorrhea and idiopathic hypogonadotropic hypogonadism
- Male infertility treatment preserving spermatogenesis (unlike GnRH agonists)
- Ovulation induction in anovulatory females
Dosage Protocols
The following reflects doses used in published research studies. This is not medical advice. Consult a qualified healthcare professional.
| Beginner | Diagnostic 100 mcg SC single dose (LH/FSH stimulation test) |
| Intermediate | Pulsatile pump for hypogonadotropic hypogonadism — clinician-directed |
| Advanced | Pulsatile ovulation induction — reproductive medicine only |
| Cycle Duration | Pulsatile: ovulation induction or puberty induction cycles |
FDA-approved (Factrel, Lutrepulse — now largely discontinued in U.S.). Still used internationally. Distinct from GnRH agonists (leuprolide) which cause desensitization.
Use our Reconstitution Calculator to determine exact syringe units for your protocol.
Routes of Administration
Subcutaneous Injection High
Diagnostic bolus route.
Intravenous Pulsatile (pump) 100%
Clinical pulsatile therapy via programmable pump — mimics endogenous GnRH pulses.
Read our full Routes of Administration Guide for detailed comparison of all delivery methods.
Stacking Protocols
Popular research stacks involving Gonadorelin (GnRH):
TRT Adjunct (off-label community use)
Community/TRT clinic use: gonadorelin 100-200 mcg 2-3x weekly (as a substitute for hCG) to maintain testicular function on TRT. Not FDA-approved for this indication.
Explore our complete Peptide Stacking Guide for more combinations and safety considerations.
Reconstitution
| Storage | Refrigerate at 2-8°C after reconstitution. Do not freeze reconstituted solution. |
|---|
Typical vial sizes: 100-500 mcg. Add bac water slowly down the side of the vial, swirl gently — do not shake. Use insulin syringe for precise dosing.
Need exact syringe measurements?
Amino Acid Sequence
pyroGlu-His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-Gly-NH2
Side Effects & Safety
- Flushing, nausea (acute injection)
- Multiple gestation risk with ovulation induction
- Injection site reactions (pump therapy)
- OHSS risk in ovulation induction protocols
Safety & Contraindications
This information is for educational purposes only. Consult a qualified healthcare provider before using any peptide.
Hormone-Sensitive Cancers
Pregnancy / Lactation
Bleeding Disorders
Active Skin Infection at Injection Site
FDA Safety Information
FDA labeling notes hypersensitivity reactions; generally well-tolerated at diagnostic doses.
Pharmacokinetics
| Half-Life | ~2-4 minutes |
|---|---|
| Storage | Store lyophilized peptide at -20°C (long-term) or 2-8°C (short-term, under 30 days). Reconstituted: refrigerate at 2-8°C and use within 28-30 days. Protect from light. Do not freeze reconstituted solution. |
Synergistic Compounds
The following compounds have been studied alongside Gonadorelin (GnRH) for potential complementary or synergistic effects:
Learn More
References & Further Reading
Latest News & Research
View all articles →
FDA Staff Reviewers Say ‘No’ to 7 Compounded Peptides Ahead of July PCAC Vote
FDA staff reviewers urged against adding seven popular peptides to the 503A bulks list ahead of the July PCAC meeting, citing weak human data and safety uncertainty.
FDA reviewers urge ‘no’ on BPC-157, TB-500, MOTS-c ahead of July 2026 compounding vote
FDA reviewers’ June 29 briefings recommend against listing seven popular peptides for 503A compounding, citing limited human data and immunogenicity risk.
Medicare Starts Paying for Obesity Drugs Today — Bridge Program Opens $50 Access for Millions
Medicare's new $50 Bridge program covering Wegovy, Zepbound, Foundayo, and oral Wegovy for obesity launched July 1 — the first Medicare weight-loss benefit.
FDA staff urges caution on compounded peptides ahead of July advisory meeting
Ahead of the July 23–24 Pharmacy Compounding Advisory Committee meeting, FDA staff briefings recommend against listing seven popular peptides for compounding.