Triptorelin Peptide | Buy Triptorelin UK | Research Use Only

Triptorelin — also known as Decapeptyl, D-Trp6-GnRH, and [D-Trp⁶]-LHRH — is a synthetic decapeptide superagonist analogue of gonadotropin-releasing hormone (GnRH / LHRH) with the sequence pGlu-His-Trp-Ser-Tyr-D-Trp-Leu-Arg-Pro-Gly-NH₂, differing from endogenous GnRH by a single D-tryptophan substitution at position 6 that confers 13-fold greater LH-releasing activity, 21-fold greater FSH-releasing activity, and substantially enhanced resistance to enzymatic degradation compared to native GnRH — producing, on acute administration, a transient gonadotropin surge followed by profound, sustained pituitary GnRH receptor desensitisation, downregulation, and consequent suppression of LH, FSH, testosterone, and oestrogen to castrate levels within 2–4 weeks — making it the definitive research tool for the hypothalamic-pituitary-gonadal (HPG) axis, GnRH receptor pharmacology, receptor desensitisation biology, and hormone-dependent oncology models. Buy Triptorelin in the UK from Peptides Lab UK with >99% HPLC-verified purity, batch-specific COA, and fast UK dispatch for laboratory and in vitro research use only.

Distributed by Peptides Lab UK in lyophilised format for controlled laboratory research. Each batch is independently verified for purity. This compound is handled strictly in pre-clinical and research settings, distinct from any licensed pharmaceutical formulation.

What Is Triptorelin?

Triptorelin (pGlu-His-Trp-Ser-Tyr-D-Trp-Leu-Arg-Pro-Gly-NH₂) is a synthetic decapeptide analogue of the endogenous hypothalamic hormone gonadotropin-releasing hormone (GnRH), also designated luteinising hormone-releasing hormone (LHRH). It was first synthesised in the 1970s as part of Andrew Schally’s Nobel Prize-winning programme exploring GnRH analogues — which established the foundational framework for all GnRH agonist research — and has since become one of the most extensively characterised GnRH analogues in both pre-clinical and clinical literature, with pharmaceutical approvals across prostate cancer, endometriosis, uterine fibroids, central precocious puberty, and gender-affirming hormone therapy in multiple jurisdictions including the US (FDA, 2000) and EU (1986).

The structural basis of triptorelin’s superagonist activity is its D-tryptophan substitution at position 6 — the position occupied by glycine in native GnRH. This single D-amino acid modification achieves two critical pharmacological effects simultaneously: dramatically increased binding affinity for the GnRH receptor on pituitary gonadotrophs, and substantially enhanced resistance to peptidase-mediated enzymatic cleavage — extending in vivo half-life and duration of receptor engagement beyond what native GnRH can achieve. The resulting pharmacodynamic profile — a large initial gonadotropin surge followed by progressive receptor desensitisation and suppression — is the defining biphasic axis of all GnRH agonist research.

Triptorelin is the benchmark GnRH agonist superagonist in receptor pharmacology research, used as the reference D-Trp6-GnRH compound in head-to-head comparisons with leuprolide (D-Leu6), goserelin (D-Ser(tBu)6), buserelin (D-Ser(tBu)6), and nafarelin (D-Nal6) — allowing systematic structure-activity relationship investigations within the GnRH analogue class.

Also Known As

• Decapeptyl (Ipsen)
• Diphereline / Gonapeptyl (Ferring Pharmaceuticals)
• Trelstar / Triptodur (Watson Pharmaceuticals / Arbor)
• D-Trp6-GnRH / [D-Trp⁶]-LHRH
• CAS No. 57773-63-4

How Does Triptorelin Work?

GnRH Receptor Binding — Superagonist Mechanism

Triptorelin binds with high affinity to the gonadotropin-releasing hormone receptor (GnRHR) — a seven-transmembrane Gq/11-coupled GPCR expressed on the surface of anterior pituitary gonadotroph cells. Unlike native GnRH, which is released in discrete pulses of 60–120 minutes and whose receptor engagement is therefore inherently transient, triptorelin’s D-Trp6 substitution gives it substantially greater receptor affinity and resistance to peptidase cleavage — resulting in prolonged, continuous receptor occupancy rather than the pulsatile stimulation pattern required for sustained gonadotropin secretion.

The Biphasic Response — Flare Followed by Suppression

Triptorelin’s pharmacodynamic profile follows a characteristic two-phase pattern that is central to its value as a research tool:

Phase 1 — Acute Agonist Surge (Days 1–14): Initial administration produces a transient but substantial surge in LH, FSH, oestradiol, and testosterone as the GnRHR is acutely activated. This “flare” effect reflects full agonist activity at the receptor before desensitisation takes hold and is pharmacologically identical to an amplified version of endogenous GnRH stimulation.

Phase 2 — Desensitisation and Suppression (Days 14–28+): Continuous GnRHR occupancy triggers receptor internalisation, uncoupling from Gq/11 signalling, and profound downregulation of both GnRHR expression and downstream gonadotroph responsiveness. The pituitary gonadotrophs enter a state of functional quiescence — ceasing to secrete LH and FSH in response to either exogenous or endogenous GnRH — resulting in progressive suppression of gonadal steroidogenesis. Serum testosterone falls to castrate levels (typically ≤50 ng/dL) within 2–4 weeks of continuous administration, and oestradiol undergoes equivalent suppression in female research models.

GnRHR mRNA Regulation and Pituitary Plasticity

Pulse exposure of pituitary cells to 0.1 nM triptorelin in vitro — using a physiologically relevant 3-minute pulse paradigm — increased GnRHR mRNA levels by 77–88% in anterior pituitary cells, confirming that acute pulsatile triptorelin stimulation upregulates its own receptor expression. This GnRHR autoregulatory property is fundamental to understanding pituitary plasticity, the divergence between agonist and antagonist pharmacology at the receptor level, and the molecular basis of the flare response. Continuous exposure, by contrast, downregulates GnRHR expression — the molecular basis of sustained suppression.

Direct Anti-Proliferative GnRHR Activity

Beyond gonadal steroidogenesis suppression, triptorelin exerts direct anti-proliferative effects in cancer cells that express GnRHR above a threshold level. Receptor binding in these tumour cells activates inositol phosphate (IP) production and engages distinct intracellular signalling pathways from those mediating gonadotropin release — including MAPK/ERK-independent anti-proliferative programmes. Structure-activity relationship studies confirmed that D-Trp6 analogues (including triptorelin), D-Leu6 analogues (including leuprolide), D-Ala6 and D-Arg6 analogues all retain both agonist and direct anti-proliferative activity in GnRHR-expressing tumour cell lines — establishing triptorelin as the D-Trp6 reference compound for oncological GnRHR pharmacology studies.

Radiolabelled Analogue Applications — Receptor Imaging

¹⁷⁷Lu-labelled DOTA-triptorelin conjugates have been evaluated in experimental oncology imaging settings — demonstrating high GnRHR binding affinity, efficient tumour uptake, and rapid clearance from non-target tissues — establishing triptorelin’s peptide scaffold as a validated receptor-targeting vector for molecular imaging probe development and theranostic GnRHR-targeted peptide research.

LHβ mRNA and Gonadotropin Gene Regulation

Triptorelin-induced alterations in LHβ mRNA expression in pituitary gonadotrophs provide a validated molecular readout of GnRHR engagement used in quantitative PCR-based studies of pituitary gene regulation. Triptorelin’s ability to both increase (under pulsatile conditions) and decrease (under continuous exposure) LHβ mRNA makes it an indispensable tool for studying the transcriptional regulatory mechanisms that govern gonadotropin synthesis in the context of variable GnRH stimulation frequency and amplitude.

What Does Triptorelin Do in Research?

In laboratory and pre-clinical settings, triptorelin is studied as the definitive GnRH superagonist research tool across HPG axis biology, neuroendocrinology, oncology, reproductive physiology, and receptor pharmacology:

• GnRH receptor pharmacology — binding affinity, Gq/11-coupled IP₃/DAG signalling, receptor internalisation, trafficking, and downregulation kinetics
• HPG axis biology — LH and FSH pulsatility, gonadotropin surge mechanisms, and hypothalamic-pituitary signalling
• Pituitary desensitisation and receptor downregulation — GnRHR mRNA regulation, gonadotroph quiescence, and research applications kinetics post-withdrawal
• Pituitary plasticity research — receptor resensitisation, GnRHR expression autoregulation, and pulse frequency-dependent transcriptional responses
• Testosterone suppression and androgen deprivation models — chemical castration, androgen receptor downstream biology, and prostatic involution
• Oestrogen suppression models — hypothalamic-pituitary-ovarian axis, oestradiol suppression, and oestrogen-dependent tumour models
• Prostate cancer biology — hormone-sensitive prostate cancer models, PSA suppression, GnRHR-expressing tumour cell direct anti-proliferative mechanisms
• Breast and ovarian cancer models — GnRHR expression in hormone-dependent tumour lines, direct and indirect anti-proliferative mechanisms
• Endometriosis pre-clinical models — oestrogen-dependent lesion suppression and HPG axis pharmacology
• Precocious puberty research — central precocious puberty models, gonadotropin suppression, and bone age modulation
• Reproductive biology and ART research — controlled ovarian stimulation protocols, LH surge suppression, IVF pituitary downregulation, and minimal dose desensitisation studies
• GnRH agonist vs antagonist comparative pharmacology — triptorelin vs cetrorelix, ganirelix, degarelix; receptor mRNA regulation comparison; onset kinetics
• GnRH analogue structure-activity relationships — D-Trp6 vs D-Leu6, D-Ser(tBu)6, D-Nal6 and D-Ala6 substitutions; receptor binding, IP production, anti-proliferative ranking
• Computational GnRH receptor modelling — receptor-ligand docking, signal transduction kinetics simulation, and receptor trafficking prediction
• Radiolabelled triptorelin imaging — ¹⁷⁷Lu-DOTA conjugates, GnRHR expression mapping, tumour biodistribution, and theranostic peptide vector development
• Neuroendocrine regulation — hypothalamic GnRH neuron biology, kisspeptin-GnRH axis, and feedback loop characterisation
• Testosterone and bone metabolism — androgen deprivation-induced osteopenia, bone resorption markers, and GnRH agonist-mediated skeletal biology
• Metabolic consequences of androgen deprivation — insulin sensitivity, body composition, dyslipidaemia, and cardiovascular risk parameter research

What Do Studies Say About Triptorelin?

Superagonist Potency vs Native GnRH

Pre-clinical pharmacological studies confirmed that triptorelin produces 13-fold greater LH-releasing activity and 21-fold greater FSH-releasing activity compared to native GnRH on a molar basis in rodent models — establishing the quantitative basis of its superagonist classification and directly demonstrating how D-Trp6 substitution amplifies receptor engagement beyond any achievable with the endogenous decapeptide.

GnRHR mRNA Regulation — Agonist vs Antagonist Divergence

The landmark PNAS study by Kovacs, Schally, and colleagues confirmed that 3-minute pulsatile stimulation of anterior pituitary cells with 0.1 nM triptorelin increased GnRHR mRNA by 77–88% — establishing the receptor’s capacity for agonist-driven upregulation under pulsatile conditions. By contrast, chronic administration in ovariectomised rats produced a 41% suppression of GnRHR mRNA, while the GnRH antagonist cetrorelix produced a 73% suppression via a different, indirect mechanism. This comparative dataset established the divergent molecular mechanisms of GnRH agonists and antagonists at the receptor gene expression level — a foundational reference for GnRH receptor pharmacology.

Triptorelin vs Leuprolide — Time to Castration

A randomised controlled trial comparing triptorelin pamoate to leuprolide acetate in men with advanced prostate cancer confirmed that both compounds produced equivalent rates of castration and PSA response, but that time-to-castrate levels was longer for triptorelin — providing a pharmacokinetic comparison dataset that directly informs GnRH agonist selection and dosing protocol research.

Direct Anti-Proliferative GnRHR Activity — Structure-Activity Profiling

The PMC study by Franklin, Bhatt and colleagues systematically evaluated triptorelin alongside a panel of D-amino acid-substituted GnRH analogues in GnRHR-expressing prostate cancer cell lines. The study confirmed that triptorelin (D-Trp6) ranked among the most potent direct anti-proliferative GnRH agonists — with sub-nanomolar receptor binding affinity and inositol phosphate EC50 — and identified that methylated D-Trp6 triptorelin variants could retain equivalent or enhanced anti-proliferative potency, establishing structure-activity insights for next-generation GnRHR-targeting oncological research tools.

IVF Pituitary Desensitisation — Minimal Effective Dose

Controlled dose-finding studies in IVF protocols determined that 15 µg/day triptorelin acetate was sufficient to suppress a premature LH surge during controlled ovarian stimulation, and that 50 µg was pharmacodynamically equivalent to 100 µg — demonstrating the plateau in pituitary desensitisation achievable at submaximal doses and establishing dose-response relationships for GnRHR saturation that are directly relevant to receptor biology research.

¹⁷⁷Lu-DOTA-Triptorelin — Molecular Imaging Research

Radiolabelled DOTA-triptorelin conjugates demonstrated high GnRHR binding affinity, efficient tumour uptake in GnRHR-expressing xenograft models, and rapid clearance from non-target tissues — establishing the triptorelin backbone as a validated GnRH receptor-targeting vector for theranostic peptide probe development and receptor expression mapping by nuclear imaging modalities.

Key Cited Studies

• Schally AV et al. (1971) — Gonadotropin-releasing hormone: one polypeptide regulates the secretion of luteinising and follicle-stimulating hormones. Science 173(4001):1036–1038. DOI: 10.1126/science.173.4001.1036. PMID: 4938639
• Kovacs M, Schally AV, Csernus B, Rekasi Z (2001) — Comparison of mechanisms of action of LHRH antagonist cetrorelix and LHRH agonist triptorelin on gene expression of pituitary LHRH receptors in rats. PNAS 98(23):13311–13316. DOI: 10.1073/pnas.211442598. PMID: 11606775
• Heyns CF et al. (2003) — Triptorelin compared with leuprolide in the treatment of advanced prostate cancer. BJU Int 92(3):226–231. DOI: 10.1046/j.1464-410X.2003.04308.x. PMID: 12887467
• Franklin J, Bhatt R, Bhatt S, Moorjani M et al. (2012) — Probing the GnRH receptor agonist binding site identifies methylated triptorelin as a new anti-proliferative agent. PMC 3906704. DOI: 10.1530/ERC-13-0109
• Lahlou N, Carel JC, Chaussain JL, Roger M (2000) — Pharmacokinetics and pharmacodynamics of GnRH agonists: clinical implications in pediatrics. J Pediatr Endocrinol Metab 13 Suppl 1:723–737. PMID: 10969915
• Drieu la Rochelle C et al. (2004) — Minimal daily dose of triptorelin needed to suppress a premature LH surge during IVF. Hum Reprod 19(2):305–310. DOI: 10.1093/humrep/deh072

Triptorelin vs Other GnRH Agonists and Antagonists in Research

Feature	Triptorelin	Leuprolide	Goserelin	Degarelix (GnRH Antagonist)
Compound Type	Synthetic GnRH decapeptide agonist	Synthetic GnRH nonapeptide agonist	Synthetic GnRH decapeptide agonist	Synthetic GnRH peptide antagonist
Position 6 Substitution	D-Trp (D-tryptophan)	D-Leu (D-leucine)	D-Ser(tBu) (D-serine tert-butyl ether)	Multiple — competitive antagonist design
LH-Releasing Potency vs GnRH	13-fold greater	~100-fold greater (depot formulations)	Comparable superagonist profile	Competitive blockade — no initial release
FSH-Releasing Potency vs GnRH	21-fold greater	Comparable	Comparable superagonist profile	Immediate suppression — no initial release
Initial Gonadotropin Surge (Flare)	Yes — 1–14 days	Yes — 1–14 days	Yes — 1–14 days	No — immediate suppression
Time to Castrate Testosterone	~3–4 weeks	~3–4 weeks	~3–4 weeks	~3 days (faster onset)
GnRHR mRNA Effect (Pulsatile)	Upregulates +77–88%	Comparable	Comparable	Downregulates indirectly
GnRHR mRNA Effect (Continuous)	Downregulates –41%	Comparable	Comparable	Downregulates –73% (more complete)
Anti-Proliferative Direct Activity	Yes — GnRHR-expressing tumour cells	Yes	Yes	Limited evidence
Radiolabelled Probe Development	Yes — ¹⁷⁷Lu-DOTA-triptorelin	Yes — various radiolabelled conjugates	Yes	Limited
Reference Compound Role	D-Trp6-GnRH SAR benchmark	D-Leu6-GnRH SAR benchmark	Implant formulation benchmark	GnRH antagonist reference
Best Research Use	GnRH receptor pharmacology, HPG axis, SAR benchmark, oncology	HPG axis suppression, prostate cancer models	Sustained-release GnRH agonist models	Rapid suppression models, no-flare protocols

Quality & Purity Assurance

Every batch of Triptorelin from Peptides Lab UK is:

• >99% pure — HPLC and mass spectrometry verified
• Supplied with a full Certificate of Analysis (COA) on request
• Lyophilised powder for maximum stability and long shelf life
• Manufactured under strict, controlled laboratory conditions
• Consistent batch-to-batch quality for reproducible research results

Buy Triptorelin UK — Product Specifications

Property	Detail
Full Name	Triptorelin / D-Trp6-GnRH
Also Known As	Decapeptyl, Diphereline, Gonapeptyl, Trelstar, [D-Trp⁶]-LHRH
Sequence	pGlu-His-Trp-Ser-Tyr-D-Trp-Leu-Arg-Pro-Gly-NH₂
Amino Acids	10 (decapeptide)
Molecular Weight	1,311.5 Da
Molecular Formula	C₆₄H₈₂N₁₈O₁₃
CAS Number	57773-63-4
Primary Receptor	GnRH Receptor (GnRHR) — Gq/11-coupled GPCR
LH Potency vs Native GnRH	13-fold greater
FSH Potency vs Native GnRH	21-fold greater
Purity	>99% (HPLC verified)
Form	Lyophilised powder
Storage	Store dry at -20°C; protect from light
Solubility	Sterile water or bacteriostatic water; highly water-soluble

Triptorelin Research Applications

Triptorelin peptide UK is supplied strictly for the following in vitro and pre-clinical research uses:

• GnRH receptor pharmacology — binding affinity, Gq/11 signalling, internalisation, trafficking, and downregulation
• HPG axis biology — LH/FSH pulsatility, gonadotropin surge mechanism, and hypothalamic-pituitary signalling
• Pituitary desensitisation and GnRHR mRNA regulation — receptor upregulation (pulsatile) and downregulation (continuous) research
• Testosterone suppression and androgen deprivation — chemical castration models, androgen receptor downstream biology
• Oestrogen suppression — hypothalamic-pituitary-ovarian axis and oestrogen-dependent tumour models
• Prostate cancer biology — GnRHR-mediated anti-proliferative activity, PSA suppression, and hormone-sensitive cancer models
• Breast and ovarian cancer research — hormone-dependent GnRHR-expressing tumour line pharmacology
• Endometriosis models — oestrogen-dependent lesion suppression and HPG axis intervention
• Precocious puberty — gonadotropin suppression and bone age modulation research
• ART and reproductive biology — IVF pituitary downregulation, LH surge suppression, minimal dose desensitisation
• GnRH agonist vs antagonist comparative pharmacology — triptorelin vs cetrorelix/degarelix mechanism divergence
• GnRH analogue structure-activity relationships — D-amino acid position 6 substitution benchmark
• Radiolabelled GnRH receptor imaging — ¹⁷⁷Lu-DOTA triptorelin conjugate and GnRHR-targeted theranostic research
• Neuroendocrine biology — kisspeptin-GnRH axis, hypothalamic neuron feedback, and pulse amplitude modelling
• Bone and metabolic consequences of androgen deprivation — osteopenia, insulin sensitivity, and cardiovascular risk parameter research

Why Buy Triptorelin UK from Peptides Lab UK?

Peptides Lab UK is a trusted UK peptides supplier providing research-grade compounds verified by independent HPLC testing. When you buy Triptorelin in the UK from us, you receive:

99% purity, HPLC and MS verified, third-party tested

• Full COA documentation per batch
• Fast same-day UK dispatch with tracked delivery
• Competitive pricing with bulk research discounts available
• Trusted by researchers across the UK and Europe

Research Disclaimer

All products supplied by Peptides Lab UK are intended strictly for in vitro laboratory research and scientific study use only. They are not intended for human consumption, veterinary use, or any medical or therapeutic application. The research-grade lyophilised triptorelin supplied by Peptides Lab UK is not a pharmaceutical product and is distinct from licensed pharmaceutical triptorelin formulations (Decapeptyl, Trelstar, Triptodur, Diphereline, Gonapeptyl) approved by the MHRA, FDA, or other regulatory authorities for clinical use in humans. Triptorelin is a potent GnRH receptor agonist with significant hormonal activity — it must not be self-administered or used outside a controlled laboratory environment. All citations on this page refer to published pre-clinical and peer-reviewed clinical pharmacology research and do not constitute a claim of safety or therapeutic efficacy for the research compound supplied herein. Peptides Lab UK accepts no liability for any misuse of research compounds. By purchasing, you confirm that you are a qualified researcher and that the product will be used solely within a controlled laboratory environment in compliance with all applicable UK laws, regulations, and institutional guidelines.