Not Approved (US) Sexual & Reproductive Health

Buserelin

also known as: Suprecur, Suprefact, Bigonist, Profact

A GnRH agonist widely used in Canada, the UK, Germany, and other markets (Suprecur, Suprefact) for prostate cancer, endometriosis, and IVF downregulation — but never FDA-approved in the United States.

A synthetic nonapeptide GnRH agonist structurally related to leuprolide, marketed internationally as Suprefact (SC injection and nasal spray) and Suprecur (nasal spray and SC depot) by Sanofi and Cheplapharm for prostate cancer, endometriosis, and IVF controlled-ovarian-stimulation downregulation. Buserelin has never been FDA-approved in the United States; its absence from US practice reflects commercial rather than safety factors — leuprolide and goserelin secured the US market first.

Mechanism of action

Pituitary GnRH-receptor agonism — chronic exposure desensitizes the receptor and suppresses LH, FSH, testosterone, and estradiol after an initial flare. Mechanism identical to leuprolide, triptorelin, and goserelin.

Primary uses

  • Advanced prostate cancer (ex-US)
  • Endometriosis (ex-US)
  • Uterine fibroids (ex-US)
  • IVF downregulation in long-protocol controlled ovarian stimulation (ex-US)

Typical dosing

0.5 (SC daily); 400–1200 mcg (intranasal daily); 6.3 (2-month depot); 9.45 (3-month depot) mg daily SC, daily-divided intranasal, or 2–3 monthly depot (subcutaneous, intranasal, or SC depot)

Prostate cancer: 500 mcg SC every 8 h for 7 days then 200 mcg nasal three times daily, or 6.3 mg SC depot every 2 months. Endometriosis / IVF: 900–1200 mcg intranasal daily. Not available in the United States.

Regulatory status

Approved and marketed across Canada, the UK, Germany, Australia, and much of Europe as Suprefact (Sanofi) and Suprecur (Cheplapharm/Sanofi) in SC daily, nasal spray, and 2-/3-month SC depot formulations. Indications include prostate cancer, endometriosis, uterine fibroids, and IVF downregulation. Not FDA-approved in the United States; the molecule was never commercially pursued for US approval.

References

  1. [other] Suprefact (buserelin acetate) Product Monograph. Sanofi-Aventis Canada.
  2. [other] Suprefact Summary of Product Characteristics. Electronic Medicines Compendium (eMC), United Kingdom.
  3. [review] Del Moral-Sanchez JM, et al. "Worldwide Availability of GnRH Agonists in Oncology and Reproductive Medicine." Pharmaceutics, 2021;13:1080 (regulatory comparison).

Related peptides

Leuprolide

The prototypical long-acting GnRH agonist, FDA-approved across multiple formulations (Lupron Depot, Eligard, Fensolvi, Camcevi) for advanced prostate cancer, endometriosis, central precocious puberty, uterine fibroids, and IVF protocols.

Triptorelin

A widely used long-acting GnRH agonist — FDA-approved as Trelstar for advanced prostate cancer and as Triptodur for pediatric central precocious puberty; approved internationally (Decapeptyl, Gonapeptyl) for endometriosis, uterine fibroids, and female infertility protocols.

Goserelin

AstraZeneca's Zoladex — a long-acting GnRH agonist delivered as a subcutaneous biodegradable implant. FDA-approved for advanced prostate cancer, advanced breast cancer in premenopausal women, endometriosis, and endometrial thinning prior to ablation.

Gonadorelin

The native GnRH decapeptide — the hypothalamic signal that drives LH/FSH release and downstream testosterone/estradiol production. Historically FDA-approved (Factrel, Lutrepulse), now widely used in TRT-adjacent fertility protocols as a testicular-preservation alternative to HCG.
Disclaimer

This entry is for educational purposes only and does not constitute medical advice. Dosing information reflects published regulatory or research data and is not a recommendation. Many compounds described here are not approved for human use in the United States. Consult a licensed medical professional before considering any peptide therapy.