Cetrorelix Acetate Research Grade Peptide (GnRH Antagonist) Supplier — UPOR Biotech
Cetrorelix Acetate (SB-75) — synthetic decapeptide GnRH/LHRH antagonist with potent competitive blockade of the pituitary GnRH receptor. It produces rapid, dose-dependent suppression of LH and FSH without the initial stimulatory flare-up characteristic of GnRH agonists — the defining advantage for fertility and hormone-sensitive research. Supplied as a lyophilized acetate salt, ≥98% HPLC purity, Research Grade (RUO) — bulk research peptide supplier from UPOR Biotech.
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Cetrorelix acetate (CAS 145672-81-7) is a synthetic decapeptide GnRH/LHRH antagonist (SB-75) with the sequence Ac-D-2-Nal-D-4-Cl-Phe-D-3-Pal-Ser-Tyr-D-Cit-Leu-Arg-Pro-D-Ala-NH₂. It is supplied as the lyophilized acetate salt (free base C₇₀H₉₂ClN₁₇O₁₄, MW 1431.06 g/mol; acetate C₇₂H₉₆ClN₁₇O₁₆, MW 1491.09 g/mol). Mechanistically, cetrorelix is a competitive antagonist at the pituitary GnRH receptor — it occupies the receptor without activating it, producing rapid, dose-dependent suppression of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) without the initial stimulatory “flare-up” characteristic of GnRH agonists. This receptor blockade inhibits gonadotropin release and the downstream production of sex steroids, enabling controlled study of the hypothalamic-pituitary-gonadal (HPG) axis. Cetrorelix is the active pharmaceutical ingredient of Cetrotide, cited here strictly as an RUO reference only for research applications — never as a therapeutic claim.
As a Research Grade (RUO) bioactive peptide, cetrorelix acetate is positioned for IVF and assisted-reproduction research (prevention of premature LH surge), hormone-sensitive prostate cancer studies, endometriosis and uterine fibroid research, and HPG axis pharmacology. Its rapid LH/FSH suppression without flare-up makes it a preferred tool in fertility research models where controlled gonadotropin levels are required. Research Use Only (RUO) — not for human diagnostic or therapeutic use. UPOR Biotech manufactures under ISO 9001, cGMP, and FDA facility registration quality systems, with each lot released with full documentation. Supplied lyophilized in sealed vials as 1 mg, 5 mg, 10 mg, or 50 mg presentations with a 2-year shelf life at -20°C.
Cetrorelix vs Leuprolide — GnRH Antagonist (No Flare-Up) vs GnRH Agonist (Flare-Up)
Cetrorelix is a GnRH receptor antagonist — it binds the pituitary GnRH receptor directly and competitively, blocking LH/FSH release immediately with no initial stimulatory phase. Leuprolide, a GnRH agonist, first stimulates the receptor and triggers a transient hormonal “flare-up” (surge of LH/FSH and downstream testosterone/estrogen) before receptor desensitization produces suppression days later. This mechanistic difference is central to fertility research: antagonists like cetrorelix provide rapid, predictable gonadotropin control without the flare, whereas an agonist’s transient stimulation can confound ovulation-induction and hormone-sensitive experimental models.
Technical Specifications
| Property | Specification |
|---|---|
| Product Name | Cetrorelix Acetate Research Grade Peptide — GnRH Antagonist (RUO) |
| Synonyms | Cetrorelix; SB-75; Cetrorelix Acetate |
| CAS Number | 145672-81-7 |
| Peptide Class | Synthetic decapeptide GnRH/LHRH antagonist |
| Sequence | Ac-D-2-Nal-D-4-Cl-Phe-D-3-Pal-Ser-Tyr-D-Cit-Leu-Arg-Pro-D-Ala-NH₂ |
| Molecular Formula (Acetate Salt) | C₇₂H₉₆ClN₁₇O₁₆ |
| Molecular Formula (Free Base) | C₇₀H₉₂ClN₁₇O₁₄ |
| Molecular Weight (Acetate Salt) | 1491.09 g/mol |
| Molecular Weight (Free Base) | 1431.06 g/mol |
| Salt Form | Acetate salt (lyophilized) |
| Mechanism | Competitive antagonist at the pituitary GnRH receptor — rapid LH/FSH suppression without flare-up |
| Purity (HPLC) | ≥98.0% |
| Peptide Content | ≥85% |
| Appearance | White to off-white lyophilized powder |
| Solubility | Soluble in sterile water, saline, or dilute buffer |
| Endotoxin Level | ≤1.0 EU/mg |
| Water Content | ≤5.0% |
| Counter-ion | Acetate |
| pH (Reconstituted) | 4.0 – 6.0 (suitable range) |
| Heavy Metals | ≤10 ppm |
| Storage | -20°C, protected from light and moisture |
| Reconstitution | Sterile water, saline, or dilute buffer; avoid repeated freeze-thaw cycles |
| Grade | Research Grade (RUO) |
| Applications | IVF & assisted-reproduction, hormone-sensitive prostate cancer, endometriosis & uterine fibroid research, HPGA pharmacology |
| Certifications | ISO 9001, cGMP, FDA facility registration |
| Packaging | 1 mg / 5 mg / 10 mg / 50 mg sealed vials |
| Shelf Life | 2 years (at -20°C, protected from light and moisture) |
| Disclaimer | Research Use Only (RUO) — not for human diagnostic or therapeutic use |
Key Benefits — Cetrorelix Acetate
Potent GnRH Receptor Antagonism
Cetrorelix is a competitive GnRH receptor antagonist — it binds the pituitary GnRH receptor directly, blocking endogenous GnRH signaling without activation. This provides immediate, reversible gonadotropin suppression that is tightly controllable in receptor-binding and HPG axis research.
GnRH Receptor AntagonistRapid LH/FSH Suppression Without Flare-Up
Unlike GnRH agonists, cetrorelix suppresses LH and FSH release rapidly and dose-dependently with no initial stimulatory flare-up. This eliminates the confounding hormone surge seen with agonists, making it the preferred tool in fertility and hormone-sensitive research models.
No Flare-UpStable Acetate Salt Lyophilized Form
Supplied as the lyophilized acetate salt, cetrorelix offers excellent stability with a 2-year shelf life at -20°C, reproducible reconstitution, and convenient storage. Each lot is released with full documentation supporting consistent, batch-to-batch performance.
Lyophilized Acetate≥98% HPLC Purity Research Peptide
High-purity cetrorelix acetate at ≥98% HPLC purity with ≥85% peptide content and ≤1.0 EU/mg endotoxin. Delivered with a full COA, HPLC chromatogram, and MS — dependable for assay development and as a peptide reference standard.
≥98% HPLCApplications
IVF & Assisted-Reproduction Research
Cetrorelix prevents the premature LH surge in controlled ovarian hyperstimulation models, enabling precise timing of oocyte retrieval in IVF and assisted-reproduction research.
Hormone-Sensitive Prostate Cancer Studies
Suppression of gonadotropin-driven androgen production supports research into hormone-sensitive prostate cancer and androgen-dependent tumor model pharmacology.
Endometriosis & Uterine Fibroid Research
Rapid ovarian steroid suppression makes cetrorelix a valuable tool for studying endometriosis and uterine fibroid biology in experimental models.
Hypothalamic-Pituitary-Gonadal Axis Pharmacology
Receptor-level blockade is used to probe HPG axis regulation, GnRH receptor pharmacology, and gonadotropin feedback control in vitro and in vivo.
Gonadotropin Assay & Endocrinology Studies
As a reference antagonist, cetrorelix supports LH/FSH assay development, receptor-binding studies, and quantitative endocrinology research.
Peptide Reference Standard & Assay Development
High-purity cetrorelix acetate serves as a peptide reference standard for analytical method development, HPLC calibration, and QC assay validation.
Frequently Asked Questions
Cetrorelix acetate (SB-75) is a synthetic decapeptide GnRH/LHRH antagonist. It works by competitively blocking the pituitary GnRH receptor, preventing endogenous GnRH from binding and activating the receptor. This produces rapid, dose-dependent suppression of LH and FSH release — and, in turn, downstream sex-steroid production — without the initial stimulatory flare-up seen with GnRH agonists. The blockade is reversible upon cessation of treatment, making cetrorelix a flexible tool in fertility and hormone research models. Supplied as the lyophilized acetate salt for Research Use Only.
A GnRH antagonist like cetrorelix blocks the GnRH receptor directly, producing immediate LH/FSH suppression with no flare-up. A GnRH agonist like leuprolide initially stimulates the receptor, causing a transient LH/FSH and sex-steroid surge (flare-up) before receptor desensitization leads to suppression days later. For fertility research, cetrorelix provides instant, predictable gonadotropin control, whereas the agonist’s initial stimulatory phase can confound ovulation-induction and hormone-sensitive experimental models.
Key applications include IVF and assisted-reproduction research (preventing premature LH surge), hormone-sensitive prostate cancer studies (suppressing gonadotropin-driven androgen production), endometriosis and uterine fibroid research, and HPG axis pharmacology. Cetrorelix is also used in gonadotropin assays and as a high-purity peptide reference standard for analytical method and assay development.
Store the lyophilized powder at -20°C, protected from light and moisture. Reconstitute in sterile water, saline, or dilute buffer immediately before use. Avoid repeated freeze-thaw cycles — aliquot and store reconstituted solutions at -20°C. Under recommended conditions, the lyophilized material has a 2-year shelf life.
Every shipment includes a COA (HPLC purity ≥98.0%, peptide content, endotoxin ≤1.0 EU/mg, water content), MSDS, HPLC chromatogram, Mass Spectrometry (MS), endotoxin analysis, and complete lot traceability. UPOR Biotech operates under ISO 9001, cGMP, and FDA facility registration. All products are Research Use Only (RUO) — not for human diagnostic or therapeutic use.