PeptidePeptideGnRH agonistAntigonadotropic

Leuprolide (GnRH agonist)

Also known as Lupron · Leuprorelin · Eligard · Prostap

Written by enwyReviewed 15 Jul 20262 sources0 comments

A synthetic gonadotropin-releasing hormone (GnRH) agonist that, after an initial flare, desensitises the pituitary to suppress LH, FSH and sex-steroid production. Licensed depot drug for prostate cancer, endometriosis, uterine fibroids, central precocious puberty and as part of gender-affirming and fertility protocols.

01 Overview

Leuprolide is a nonapeptide GnRH analogue. Continuous (rather than pulsatile) receptor stimulation first transiently increases gonadotropins — the 'flare' — then downregulates GnRH receptors, driving testosterone or oestradiol to castrate/menopausal levels. This medical castration is the basis of its oncology and endocrine uses.

It is delivered as long-acting depot injections (monthly to six-monthly) or implants, making it one of the most established peptide drugs in clinical use. Its effects and adverse profile — chiefly hypogonadal symptoms and, with prolonged use, bone loss — are well documented across large trial populations.

02 Mechanism

Continuous GnRH-receptor agonism at the pituitary causes receptor desensitisation, suppressing LH/FSH and thereby gonadal sex-steroid output after an initial surge.

03 Dosing

Tier	Dose	Route	Notes
Depot (monthly)	7.5 mg	SubQ	Prostate cancer / endometriosis monthly depot; 22.5 mg (3-mo) and 45 mg (6-mo) formats also exist.

04 Effects

Effect	Magnitude	Evidence
Suppression of sex hormonesReliably lowers gonadal steroids, slowing hormone-driven cancers and endometriosis.	Testosterone/oestradiol to castrate range	Clinical
Halted pubertal progressionReverses/pauses premature pubertal development when used in children.	Arrest of precocious puberty	Clinical

05 Side effects

Effect	Severity	Frequency	Evidence
Hypogonadal symptoms (hot flushes, low libido)Hot flushes, fatigue, mood change, sexual dysfunction from low sex steroids.	Moderate	Nearly universal	Clinical
Bone mineral density lossSustained hypogonadism reduces bone density and raises fracture risk.	Moderate	Common with prolonged use	Clinical
Tumour flare (initial surge)Initial testosterone surge can transiently worsen prostate-cancer symptoms.	Moderate	Common early	Clinical

06 Legal status

United States

Prescription (Lupron/Eligard)

as of Jan 2026

United Kingdom

Prescription medicine

as of Jan 2026

07 References

GnRH agonists in prostate cancerThe Lancet Oncology (review)

Lupron Depot prescribing informationUS FDA label

08 Discussion0 comments

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This page is reference information, not medical advice. Doses and protocols are documented as they appear in the clinical literature and in practice — describing them is not a recommendation to use them. Countermeasures listed here are not a substitute for a physician. Legal status varies by jurisdiction and changes.