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approvedHormone Regulation

Leuprolide

Also known as: Lupron, Lupron Depot, Leuprorelin, Eligard, Fensolvi, Camcevi

Leuprolide is a synthetic GnRH agonist nonapeptide that is one of the most widely prescribed hormonal therapies worldwide. FDA-approved for advanced prostate cancer, endometriosis, uterine fibroids, central precocious puberty, and as an adjunct in IVF protocols, it works by initially stimulating and then profoundly suppressing the hypothalamic-pituitary-gonadal axis through receptor downregulation. Available in depot formulations lasting 1, 3, 4, or 6 months, leuprolide effectively produces a reversible medical castration, reducing testosterone or estrogen to castrate levels within 2-4 weeks of initiation.

4 cited references·5 researched benefits

Quick Answer

Leuprolide (Lupron) is a GnRH agonist that suppresses sex hormone production by downregulating pituitary GnRH receptors after an initial stimulatory flare. FDA-approved for prostate cancer, endometriosis, uterine fibroids, precocious puberty, and IVF, it is available as depot injections lasting 1-6 months. It reduces testosterone or estrogen to castrate levels, making it a cornerstone of hormone-sensitive cancer treatment.

Key Facts

Mechanism
Leuprolide is approximately 15-100 times more potent than native GnRH at the GnRH receptor due to D-amino acid substitutions that resist enzymatic degradation. Upon initial administration, it stimulates a surge of LH and FSH (the "flare" effect), transiently increasing sex steroids for 1-2 weeks. With continuous exposure, pituitary GnRH receptors are downregulated and desensitized, leading to profound suppression of LH, FSH, testosterone, and estradiol to castrate or postmenopausal levels. This chemical castration is reversible upon discontinuation. Depot formulations use biodegradable microsphere or polymer technology to provide sustained drug release over months.
Research Status
approved
Half-Life
~3 hours
Molecular Formula
C₅₉H₈₄N₁₆O₁₂
Primary Use
Hormone Regulation
Table of Contents

Benefits

  • Treats advanced prostate cancer by reducing testosterone to castrate levels — survival benefit demonstrated in multiple randomized trialsstrong
  • Relieves endometriosis-associated pain — FDA-approved with significant reduction in dysmenorrhea and pelvic pain in controlled studiesstrong
  • Controls central precocious puberty — halts premature puberty progression and preserves adult height potentialstrong
  • Shrinks uterine fibroids by 35-65% volume — used as pre-surgical adjunct to reduce bleeding and fibroid sizestrong
  • Controlled ovarian stimulation in IVF — prevents premature LH surge when used in long GnRH agonist downregulation protocolsstrong

Dosage Protocols

RouteDosage RangeFrequencyNotes
Intramuscular depot injection (prostate cancer)7.5 mg (1-month), 22.5 mg (3-month), 30 mg (4-month), or 45 mg (6-month)Per depot formulation intervalLupron Depot formulations. Antiandrogen (bicalutamide/flutamide) should be started 1-2 weeks before and continued for 2-4 weeks to block testosterone flare.
Subcutaneous depot injection (prostate cancer)7.5 mg (1-month), 22.5 mg (3-month), or 45 mg (6-month)Per depot formulation intervalEligard formulation uses ATRIGEL delivery system for subcutaneous injection.
Intramuscular depot injection (endometriosis)3.75 mg (1-month) or 11.25 mg (3-month)Monthly or every 3 months for up to 6 monthsNorethindrone acetate 5 mg daily add-back therapy recommended to reduce bone loss and vasomotor symptoms. Treatment limited to 6 months (or 12 months with add-back).
Intramuscular or subcutaneous (precocious puberty)7.5-15 mg monthly or 11.25-30 mg every 3 monthsMonthly or every 3 months, weight-based dosingLupron Depot-Ped formulations. Dose adjusted by body weight. Treatment continued until appropriate age for puberty onset.

Medical disclaimer

Dosage information is provided for educational reference only. Always follow your prescriber's instructions and consult a qualified healthcare provider before starting any peptide protocol.

Side Effects

  • Hot flashes and vasomotor symptoms — experienced by 50-80% of patients due to sex hormone suppression; the most common side effectcommon
  • Injection site reactions — pain, induration, and granuloma formation at depot injection sitescommon
  • Decreased bone mineral density — significant risk with prolonged use (>6 months); add-back therapy with low-dose hormones is recommendedserious
  • Testosterone flare — initial 1-2 week surge in testosterone can worsen prostate cancer symptoms including bone pain and urinary obstruction; mitigated with antiandrogen coverserious
  • Mood changes, depression, and cognitive effects — reported in both men and women; may affect memory and executive functioncommon
  • Sexual dysfunction — decreased libido, erectile dysfunction in men and vaginal dryness in women due to castrate hormone levelscommon
  • Cardiovascular risk — emerging data suggest increased risk of cardiovascular events with long-term androgen deprivation therapyserious

Frequently Asked Questions

What is the testosterone flare with leuprolide and how is it managed?
When leuprolide is first administered, it stimulates GnRH receptors before desensitizing them, causing a transient surge in LH and testosterone lasting 1-2 weeks (the "flare" effect). In prostate cancer patients, this can temporarily worsen symptoms including bone pain, urinary obstruction, and spinal cord compression. To prevent clinical flare, an antiandrogen (such as bicalutamide 50 mg daily) is started 1-2 weeks before the first leuprolide injection and continued for 2-4 weeks. Alternatively, GnRH antagonists like degarelix avoid the flare entirely.
How long does leuprolide take to work for endometriosis?
Leuprolide begins suppressing estrogen within 2-4 weeks, with most women achieving postmenopausal estrogen levels by 4-8 weeks. Pain relief typically begins within 4-8 weeks, though some women notice improvement sooner. Maximum benefit is usually achieved by 2-3 months. Treatment is typically limited to 6 months due to bone density concerns, though with norethindrone add-back therapy, some protocols extend to 12 months.
Is the bone density loss from leuprolide reversible?
Bone mineral density typically decreases 3-8% during a 6-month course of leuprolide. Most of this loss is reversible within 12-24 months of discontinuation, though recovery may be incomplete, especially in older patients or those with pre-existing osteopenia. Add-back therapy with norethindrone acetate 5 mg daily significantly attenuates bone loss while maintaining efficacy for endometriosis. Long-term use (>12 months) without hormonal add-back is not recommended due to fracture risk.
What is the difference between Lupron Depot and Eligard?
Both contain leuprolide acetate but use different sustained-release technologies. Lupron Depot uses biodegradable microspheres injected intramuscularly, while Eligard uses the ATRIGEL polymer system that forms a solid depot after subcutaneous injection. Both achieve equivalent testosterone suppression. Eligard is injected subcutaneously (which some patients prefer), while Lupron Depot requires intramuscular injection. Cost and insurance coverage may vary between formulations.
Can leuprolide affect fertility permanently?
Leuprolide-induced hormonal suppression is reversible. In premenopausal women, menstruation and fertility typically return within 2-3 months of stopping treatment. In men, testosterone and spermatogenesis recover within 3-6 months, though prolonged treatment (years of androgen deprivation for prostate cancer) may result in slower or incomplete recovery in some patients, particularly older men. Leuprolide is actually used in some IVF protocols, confirming its compatibility with fertility treatment.

References

  1. 1
    A potent long-acting agonist of luteinizing hormone-releasing hormone: leuprolide(1983)PubMed ↗
  2. 2
    GnRH agonists and antagonists in the treatment of prostate cancer(2004)PubMed ↗
  3. 3
    Leuprolide acetate depot for the treatment of endometriosis: a review(1996)PubMed ↗
  4. 4
    Central precocious puberty: treatment with GnRH agonists and long-term outcome(2009)PubMed ↗

Latest Research

Last updated: 2026-02-19