Reproductive & hormonal
Leuprolide
A GnRH agonist that shuts down sex-hormone production when given continuously; approved for prostate cancer, endometriosis, fibroids and early puberty.
What it is
Leuprolide is a synthetic nine-amino-acid analogue of gonadotropin-releasing hormone, more potent and longer-lasting than the natural decapeptide. Given in pulses it would stimulate the pituitary; given continuously, as every licensed form does, it desensitises the pituitary and suppresses LH, FSH and the sex hormones they control. It is a prescription medicine with depot injections lasting one, three or six months.
How it works
- 1
Binds GnRH receptors in the pituitary far more tightly than natural GnRH.
- 2
Continuous receptor occupancy desensitises the pituitary and reduces GnRH receptor numbers.
- 3
LH and FSH secretion falls, so testosterone or oestrogen production drops to castrate levels.
- 4
An initial flare of hormone release occurs in the first week before suppression takes hold.
- 5
In children, removing the pubertal hormone signal pauses pubertal progression.
What it's studied for
Reported and studied effects
- Testosterone suppressed below castrate level (50 ng/dL) within about four weeks
- Roughly 60 to 80% reduction in endometriosis pain scores in trials
- Reduced fibroid and uterine volume
- Pausing of pubertal development in central precocious puberty
- Menopausal symptoms and bone loss from induced hormone suppression
Research protocol notes
Research context onlyResearch context only - prescription medicine. Licensed regimens include 3.75 mg intramuscularly monthly or 11.25 mg every three months for prostate cancer, 3.75 mg monthly for endometriosis for up to six months, and weight-based depot dosing in central precocious puberty. Trials use testosterone below 50 ng/dL or oestradiol suppression as the biochemical endpoint and follow bone density over months.
These figures are described so you can understand what researchers did. They are not a dose, a schedule, or a suggestion — and they are not a substitute for a doctor.
Possible side effects and contraindications
Safety profile
Possible side effects
- Hot flushes and sweats
- Loss of libido and erectile dysfunction
- Bone mineral density loss with prolonged use
- Mood change and fatigue
- Tumour or symptom flare in the first weeks
- Injection-site reactions
- Raised liver enzymes (uncommon)
Contraindications and cautions
- Pregnancy and breastfeeding
- Undiagnosed abnormal vaginal bleeding
- Prior hypersensitivity to GnRH analogues
- In prostate cancer with spinal metastases, flare needs cover with an antiandrogen
A side-effect list is never complete, and these are not the only situations that warrant caution. Anything unexpected, or anything you are unsure about, should be discussed with a doctor before use.
Evidence assessment
Decades of randomised trials across four separate indications with objective endocrine endpoints, plus regulatory approval in the EU and US.
References
- 01European Medicines Agency - Eligard product information
- 02Practice Committee of the American Society for Reproductive Medicine, Treatment of pelvic pain associated with endometriosis, Fertility and Sterility 2014
References link to published literature, regulator pages or literature indexes. Where a link points to a search, it collects the peer-reviewed work on that molecule rather than a single study.
Related
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Bremelanotide (PT-141)
The melanocortin peptide approved as Vyleesi for low sexual desire in premenopausal women — an on-demand drug, not a tanning product.
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Cetrorelix
A GnRH antagonist used in fertility treatment to stop ovulation happening before egg collection.
Reproductive & hormonal
Degarelix
A GnRH antagonist that suppresses testosterone immediately, without the initial hormone flare of agonists.