Buserelin

Suprefact, Suprecur, Profact, Metrelef, HOE 766, buserelin acetate

Sexual health, hormones & signalling

Awaiting medical reviewEN ES DE FR PT ZH+ Follow for updates

Note on this profile. Buserelin is an approved prescription medicine in the UK, Canada, much of the EU and several other countries, not a research-only compound. It has never been approved in the United States. This page explains the published science. Use outside a prescription carries real risks discussed below.

Summary

Class: Synthetic nonapeptide (9 amino acids) analogue of gonadotropin-releasing hormone (GnRH); D-Ser(tBu)⁶ substitution and a C-terminal ethylamide in place of glycinamide
Mechanism: Binds pituitary GnRH receptors far more durably than natural GnRH; a brief surge of LH/FSH is followed by receptor desensitisation and a sustained shutdown of testosterone or oestrogen production
Routes studied: Subcutaneous injection, nasal spray, and subcutaneous depot implant (approved); intravenous in early pharmacology
Half-life: ~70–80 minutes (SC or IV); nasal ~1–2 hours. Depot formulations release over 2–3 months
Storage: Solution and nasal spray: room temperature per label, protect from light; nasal spray in use typically 5 weeks †. Depot: room temperature
Regulatory status: Approved (UK, Canada, several EU states); not approved in the US; cancelled in Australia

Doses are as reported in studies or by the community — never recommendations.

1What it is

Buserelin is one of the first-generation "superagonist" copies of GnRH, the hypothalamic hormone that tells the pituitary to release LH and FSH. It was developed by Hoechst in Germany in the mid-1970s and reached European markets in the mid-1980s, a few years ahead of leuprolide and goserelin in some countries. Two substitutions — a bulky protected D-serine at position 6 and an ethylamide tail — make it resistant to the enzymes that degrade natural GnRH within minutes, and raise receptor affinity many-fold.

It is a licensed hormonal treatment for prostate cancer, endometriosis and pituitary suppression during IVF, and a long-established tool in veterinary reproduction (the brand Receptal). It is not a compound with any meaningful self-directed or community use; nearly every milligram given to humans is prescribed in oncology or fertility clinics.

2How it's thought to work

Flare then suppression. for the first one to two weeks a GnRH drives LH and FSH up, which briefly raises testosterone or oestradiol. Continuous occupancy then desensitises and down-regulates the receptors, and gonadotropin output falls to castrate-range levels within about 2–4 weeks.

Prostate cancer. removing testosterone slows androgen-dependent tumour growth; a short course of an anti-androgen is often given to cover the flare.

Endometriosis. low oestrogen shrinks oestrogen-dependent lesions and stops cyclical bleeding into them.

IVF. suppressing the woman's own LH surge prevents premature ovulation so that egg retrieval can be timed precisely ("long protocol" down-regulation).

A GnRH agonist given as a nasal spray or injection. Steady stimulation replaces the natural pulse, the pituitary receptor is internalised, and gonadal hormone output falls after an initial rise.Schematic — not to scale

3What the research shows

Advanced prostate cancer

Buserelin was among the earliest GnRH shown to achieve castrate testosterone comparable to surgical castration or oestrogen therapy (Klijn & de Jong 1982, Lancet). Randomised comparisons through the 1980s found similar tumour response and survival to orchidectomy or diethylstilboestrol with fewer cardiovascular effects than oestrogen (e.g. the EORTC and multi-centre comparative studies summarised in Debruyne 1988, Am J Clin Oncol †). Modern practice regards all GnRH agonists as broadly interchangeable; buserelin simply has less market share than leuprolide or goserelin. [1]

Endometriosis

Randomised trials of intranasal buserelin against danazol reported comparable lesion regression and pain relief over 6 months, with a different side-effect profile (hypo-oestrogenic rather than androgenic) (Lemay 1984, Fertil Steril; Dmowski 1989, Fertil Steril †). [2]

Pituitary down-regulation in IVF

Buserelin, usually nasal, is one of the standard agonists in GnRH-agonist "long protocols"; meta-analyses of agonist versus antagonist protocols show similar live-birth rates with lower ovarian hyperstimulation risk in antagonist protocols (Al-Inany 2016, Cochrane Database Syst Rev). Trial evidence for buserelin specifically is embedded in those pooled analyses. [3]

Graded A/B

Breast cancer, uterine fibroids, precocious puberty

Licensed for premenopausal breast cancer in some countries on the basis of ovarian-suppression trials with this class; fibroid shrinkage before surgery and paediatric central precocious puberty are off-label or regional uses with small-trial support.

Contraception

Intranasal buserelin was explored as a hormonal contraceptive in the 1980s with high anovulation rates in small studies; development did not continue.

4Reported side effects and interactions

Literature-reported

hot flushes (the majority of patients), loss of libido and erectile dysfunction in men, vaginal dryness and reduced bone mineral density in women on prolonged courses, mood changes, headache, nasal irritation with the spray, injection-site reactions. The tumour flare in the first weeks can transiently worsen bone pain or urinary obstruction in prostate cancer; spinal-cord compression is a rare but recognised flare complication. Long-term androgen deprivation is associated with metabolic changes (weight gain, insulin resistance, lipid shifts) and bone loss.

Community-reported

essentially none documented outside prescribed use.

Theoretical. QT prolongation is a class-level consideration under androgen deprivation.

Interactions. nasal decongestants may reduce spray absorption (label advice to use them after the dose); additive effect with other sex-hormone-lowering drugs; caution with QT-prolonging medicines in prostate cancer.

Markers researchers commonly monitor

Taken from label monitoring and oncology/fertility practice:

Marker	Why it's watched
Testosterone (men)	confirms castrate-range suppression (<50 ng/dL, increasingly <20 ng/dL) after the first month.
PSA	tumour response in prostate cancer.
Oestradiol, LH, FSH (women)	confirms down-regulation before IVF stimulation or in endometriosis.
Bone mineral density (DEXA)	bone loss accrues with courses longer than 6 months or repeated courses.
Fasting glucose/HbA1c, lipid panel, weight	metabolic effects of long-term androgen deprivation.
ECG (QTc)	in men on prolonged androgen deprivation with cardiac history.

Free for everyone. Safety information is never behind a paywall.

5Reconstitution and handling

Supplied as ready-to-use solution (1 mg/mL) for injection or metered nasal spray, or as depot implants. No is involved; the calculator is not applicable. Nasal spray bottles are primed and then discarded after the label-stated in-use period.

6Commonly studied alongside

The other GnRH analogues profiled on this site (#102–#108: leuprolide, triptorelin, gonadorelin, nafarelin and related compounds), goserelin (#212), histrelin (#213), degarelix (#214, the antagonist alternative), anti-androgens given for flare cover, and add-back hormone therapy in endometriosis.

Informational cross-links. Not stack recommendations.

7Regulatory status by region

Region	Status (checked —)
United States	Never FDA-approved; not available
European Union	Nationally authorised in several member states (e.g. Germany: Profact/Suprefact and depot forms; others) †
United Kingdom	MHRA-licensed (Suprefact injection and nasal spray; Suprecur nasal spray for IVF and endometriosis); prescription-only
Australia	Suprefact injection registration cancelled on the ARTG; not currently marketed †
South Africa	Registered historically with SAHPRA †
Sport (WADA)	Prohibited in males under S2 (LH-releasing factors, buserelin named as an example); not prohibited in females

8Open questions

Is there any clinically relevant difference between buserelin and the other GnRH , or only differences in formulation and availability?
Optimal duration and add-back strategy in endometriosis to protect bone.
Whether earlier intervention with GnRH analogues in prostate cancer changes cardiovascular risk compared with antagonists.

9References

1Klijn JGM, de Jong FH (1982). Treatment with a luteinising-hormone-releasing-hormone analogue (buserelin) in premenopausal patients with metastatic breast cancer / and in prostatic cancer. Lancet. [verify exact title] PubMed · DOI
2Lemay A et al. (1984). Reversible hypogonadism induced by a luteinizing hormone-releasing hormone (LH-RH) agonist (buserelin) as a new therapeutic approach for endometriosis. Fertil Steril. PubMed · DOI
3Al-Inany HG et al. (2016). Gonadotrophin-releasing hormone antagonists for assisted reproductive technology. Cochrane Database Syst Rev. PubMed · DOI
4Sandow J (1983). Clinical applications of LHRH and its analogues. Clin Endocrinol (Oxf). PubMed · DOI
5Electronic Medicines Compendium (UK). Suprefact / Suprecur Summary of Product Characteristics (current). PubMed
6World Anti-Doping Agency. Prohibited List (current year), section S2. PubMed

References are being resolved to PubMed/DOI identifiers; links search PubMed for the citation until then.

† Being confirmed by our reviewers against current sources.

10Community

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Self-reported side effects Phase 2

Not enough data yet. 0 of the 50 members needed have logged this compound for 4+ weeks. We don't show anything below 50, so no one can be identified.

11Page history

31 Oct 2026Profile published — awaiting medical review

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