# Gonadorelin > Synthetic GnRH — the native decapeptide at the top of the pituitary-gonadal axis; pulsatile dosing switches the axis on, continuous dosing shuts it down. - Also known as: GnRH, LHRH, Gonadoliberin, Luteinizing hormone-releasing hormone, Factrel, Lutrepulse - Class: Reproductive, Peptide Hormones - FDA approved: No - Canonical page: https://americanpeptide.com/catalog/gonadorelin ## Overview Gonadorelin is synthetic gonadotropin-releasing hormone (GnRH), the ten-amino-acid hypothalamic hormone that governs reproduction. Delivered to the pituitary it triggers release of LH and FSH — but only when given in pulses: the receptor’s defining quirk is that continuous exposure desensitizes it and suppresses the very hormones a pulse would release, the paradox that underlies both fertility and hormone-suppression medicine. Gonadorelin is the manufactured form of GnRH, the master hormone of reproduction. Isolated and sequenced in 1971 — work that earned Andrew Schally a share of the 1977 Nobel Prize — it sits one step below kisspeptin in the hypothalamic-pituitary-gonadal (HPG) axis and one step above LH and FSH. Its ten residues are the switch that turns the whole reproductive cascade on. What makes GnRH biology remarkable is its dependence on rhythm. The pituitary responds to pulses, not to a steady signal: given in a pulsatile pattern gonadorelin stimulates LH and FSH and can reawaken a dormant axis, but given continuously it does the opposite — the receptor downregulates and gonadotropins fall. That single paradox splits its uses in two. Pulsatile gonadorelin was FDA-approved (Lutrepulse, via a programmable pump) for infertility from hypothalamic amenorrhea, and a version (Factrel) served as a diagnostic of pituitary function; both were later discontinued in the US. The same continuous-suppression principle is why long-acting GnRH analogs such as leuprolide are used to shut the axis down. In practice gonadorelin draws attention as the axis-signaling counterpart to hormones this catalog already covers: it acts upstream of hCG — which mimics LH at the gonad — and downstream of kisspeptin, which triggers GnRH release in the first place. Its native half-life, measured in minutes, is precisely why the pulsatile-versus-continuous distinction matters so much. ## Mechanism GnRH-receptor agonism on pituitary gonadotrophs. Pulsatile stimulation drives LH / FSH secretion; continuous stimulation desensitizes the receptor and suppresses the gonadotropins. ## Chemistry | Property | Value | | --- | --- | | Molecular formula | C55H75N17O13 | | Molecular weight | 1182.29 Da | | CAS number | 33515-09-2 | | PubChem CID | [638793](https://pubchem.ncbi.nlm.nih.gov/compound/638793) | ## Sequence ``` pGlu-His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-Gly-NH2 ``` ## Research areas Studied in: Reproductive endocrinology, HPG-axis function, Fertility, Hypogonadism. Guides on this site: - [Sexual & Reproductive Health](https://americanpeptide.com/research-areas/sexual-reproductive): Peptides studied across the HPG axis and CNS sexual-response pathways. ## Key research - Native GnRH decapeptide — the manufactured form of the hypothalamic hormone that controls LH and FSH; sequenced in 1971 (Schally, Nobel 1977). - Pulsatile vs continuous — the defining paradox: pulses stimulate the gonadotropins, continuous exposure desensitizes the receptor and suppresses them. - Approved uses (historical) — pulsatile Lutrepulse for hypothalamic-amenorrhea infertility and Factrel as a pituitary-function diagnostic; both discontinued in the US. - Axis position — acts downstream of kisspeptin (which releases GnRH) and upstream of hCG (which mimics LH at the gonad). - Short half-life — a native peptide cleared within minutes, which is why delivery pattern, not just dose, determines the effect. ## Storage, handling & synthesis **Synthesis.** Gonadorelin is the native GnRH decapeptide: an N-terminal pyroglutamate, a C-terminal glycinamide, and otherwise standard residues. Solid-phase assembly is routine, but the pyroglutamate terminus and the C-terminal amide are the two features that must be formed correctly, and the internal Ser/Tyr residues make byproduct control the main purity task. ## FAQs ### What is gonadorelin? Gonadorelin is synthetic GnRH — the natural ten-amino-acid hypothalamic hormone that tells the pituitary to release LH and FSH, the hormones that drive the gonads. ### Why does pulsatile versus continuous dosing matter? The GnRH receptor responds to rhythm: pulses stimulate LH and FSH, while continuous exposure desensitizes the receptor and suppresses them — the basis for both fertility and hormone-suppression uses. ### How does gonadorelin relate to hCG and kisspeptin? It sits between them on the reproductive axis: kisspeptin triggers GnRH (gonadorelin) release, gonadorelin drives LH and FSH, and hCG acts further down by mimicking LH directly at the gonad. ### Is gonadorelin FDA-approved? It was historically approved in the US (Lutrepulse for infertility; Factrel as a diagnostic) but both were discontinued. This page is a research and educational reference, not medical advice. ## Latest research Recent trials and publications mentioning Gonadorelin, pulled automatically from ClinicalTrials.gov and PubMed (unfiltered search results, refreshed daily). ### Recent trials - [Purpose to Evaluate the Effectiveness of the Superovulation Stimulation Protocol Using Human Chorionic Gonadotropin (hCG) by Demonstrating Its Equivalence to Standard Controlled Ovarian Stimulation Protocols in Terms of Oocytes Retrieved, Blastulation While Maintaining an Economic Advantage](https://clinicaltrials.gov/study/NCT07771283) — ENROLLING_BY_INVITATION · NA · NCT07771283 - [CaREFREE Study (Calorie Restriction, Environment and Fitness: Reproductive Effects Evaluation Study)](https://clinicaltrials.gov/study/NCT02858336) — COMPLETED · NA · NCT02858336 - [Hormonal Regulation of Puberty and Fertility](https://clinicaltrials.gov/study/NCT01511588) — COMPLETED · NCT01511588 - [Phase IIIb Study of Ribociclib + ET in Early Breast Cancer](https://clinicaltrials.gov/study/NCT05827081) — RECRUITING · PHASE3 · NCT05827081 - [A Trial to Evaluate Ovarian Suppression Following Subcutaneous ZOLADEX 10.8 mg in Premenopausal Women With Early-stage and Advanced HR+ Breast Cancer](https://clinicaltrials.gov/study/NCT07310420) — RECRUITING · PHASE1 · NCT07310420 - [QL1706 Plus Neoadjuvant Endocrine Therapy in HR-Positive/HER2-Negative Breast Cancer With a Poor Response to Neoadjuvant Chemotherapy](https://clinicaltrials.gov/study/NCT07782840) — NOT_YET_RECRUITING · PHASE2 · NCT07782840 --- Source: AmericanPeptide.com — https://americanpeptide.com/catalog/gonadorelin Data license: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Attribution: AmericanPeptide.com. Research reference only — computational and educational content, not medical advice.