Research information only. PrecisePep is an educational library. It is not medical advice and is not intended to assist, encourage or enable self-administration. The compounds documented here are research chemicals — most are not approved for human use. Read the full disclaimer.
PrecisePep/Peptide Library/Leuprolide
Hormone Suppression & Oncology
Lupron® · Lupron Depot® · Eligard® · Camcevi® · leuprorelin · GnRH agonist
A GnRH analogue that shuts the reproductive axis down by overstimulating it. Given continuously instead of in pulses, the same signal that starts puberty ends it — the clearest demonstration in medicine that pulsatility is information.
The hypothalamus releases GnRH in pulses, roughly every 60 to 120 minutes. The pituitary responds to the pulses, not to the hormone. Flatten the pattern into a continuous signal and the pituitary stops responding altogether — GnRH receptors downregulate, LH and FSH fall, and the gonads stop producing testosterone or oestrogen.
Leuprolide is built to exploit that. It is a nine-residue GnRH analogue with substitutions that make it considerably more potent than the native hormone and far more resistant to degradation, formulated as a depot that releases continuously for one to six months. The first one to three weeks produce the opposite of the intended effect — receptors are still responsive, so LH surges and sex hormone levels rise sharply. This is the flare, and in metastatic prostate cancer with spinal disease or urinary obstruction it can be dangerous enough to require antiandrogen cover or an antagonist instead.[1] After downregulation, levels fall to castrate range and stay there.
The same mechanism serves four unrelated purposes: androgen deprivation in prostate cancer, oestrogen suppression in endometriosis and fibroids, and — at the opposite end of life — halting central precocious puberty in children so that final adult height is not lost to premature epiphyseal closure.[2]
Leuprolide is a prescription medicine and this page publishes no unsupervised dosing for it. It is here because the conditions index names prostate cancer, and because it makes a point the rest of this library depends on: pulsatile and continuous exposure to the same peptide produce opposite outcomes. That is the same principle behind the no-DAC versus DAC argument on CJC-1295 and behind why teriparatide builds bone while continuous PTH destroys it. Here it is the entire therapeutic strategy.
Phase one — agonism and flare. Leuprolide binds pituitary GnRH receptors and stimulates them. LH and FSH rise, and testosterone or oestradiol rises with them, typically peaking in the first week or two. In prostate cancer this can transiently worsen bone pain, spinal cord compression or urinary obstruction; in endometriosis it can transiently worsen symptoms.
Phase two — receptor downregulation and desensitisation. Continuous occupancy causes GnRH receptor internalisation and uncoupling. Gonadotropin release falls, and sex steroid production follows it down to castrate levels within roughly two to four weeks.
Why an antagonist behaves differently. Degarelix and relugolix block the receptor rather than overstimulating it, producing suppression within days and no flare at all. That is the main clinical argument for choosing an antagonist where flare would be dangerous.
Why it is reversible in children and less so in adults. In central precocious puberty, suppression halts pubertal progression and the axis resumes on discontinuation. In adults, prolonged suppression carries cumulative consequences — bone loss in particular — that do not fully reverse.
Effects that have been reported. A study-tier entry means a result was published — not that the effect is established, reproducible, or transferable from a rodent to a person.
Highest confidenceReported in peer-reviewed literature, registered clinical trials, or regulatory filings. Note the model: much peptide literature is in vitro or rodent work, not human trial data.
Achieves and maintains castrate testosterone levels, which is the foundation of systemic treatment in hormone-sensitive advanced disease. Replaced surgical orchiectomy as the standard approach because it is reversible and acceptable to patients.
Randomised evidence supports reduction in pelvic pain through oestrogen suppression, generally with hormonal add-back therapy to limit bone loss and vasomotor symptoms.
Reduces uterine fibroid size and corrects anaemia preoperatively, making a less invasive surgical approach possible in some cases.
Halting premature pubertal progression prevents early epiphyseal fusion. One of the clearest paediatric endocrine indications, with decades of follow-up.
One-, three-, four- and six-monthly formulations exist, which substantially reduces treatment burden compared with daily administration.
Unproven — inference onlyExtrapolated from a known mechanism, receptor profile, or adjacent compound class. Biologically plausible but not directly demonstrated for this compound in this context.
GnRH agonists are used to pause puberty in gender-dysphoric adolescents. An established clinical practice in specialist services, with an evidence base that is developing and contested, and one that belongs in a clinical consultation rather than on a reference page.
Studied for preserving ovarian function during gonadotoxic chemotherapy, with mixed randomised results and continuing disagreement about the size of the effect.
Intermittent schedules have been trialled to reduce cumulative toxicity, with non-inferiority demonstrated in some settings and not others. A live clinical question rather than a settled one.
Uncontrolled reportsAggregated from research-community logs, forums, vendor literature and self-reported experience. Uncontrolled, unverified, subject to placebo, polypharmacy and product-purity confounds. Lowest evidentiary weight.
Patient reporting on androgen deprivation is dominated by hot flushes, fatigue, loss of libido, muscle loss and mood change. These are not adverse reactions in the ordinary sense — they are what removing testosterone does.
Transient worsening before improvement is widely described, and is the reason antiandrogen cover is given in high-risk prostate disease.
Patients consistently report that low-dose hormonal add-back is the difference between completing a course and abandoning it.
A depot formulation requiring specialist administration, in a drug whose effect is chemical castration, has no research-chemical market.
Adverse effects, contraindications and unknowns. The grey-market tier is where under-reporting is worst: uncontrolled use produces no systematic safety surveillance at all, so absence of a reported harm is not evidence of safety.
Highest confidenceReported in peer-reviewed literature, registered clinical trials, or regulatory filings. Note the model: much peptide literature is in vitro or rodent work, not human trial data.
The initial testosterone surge can worsen bone pain, precipitate spinal cord compression in vertebral metastases, or cause urinary obstruction. Antiandrogen cover before and during initiation, or a GnRH antagonist instead, is standard where this risk is present.
Sustained hypogonadism causes progressive bone loss and increases fracture risk. Densitometry, calcium and vitamin D, and antiresorptive or anabolic therapy where indicated are part of long-term management rather than optional additions.
Androgen deprivation is associated with insulin resistance, increased fat mass, dyslipidaemia and — in observational data — cardiovascular events, particularly in men with pre-existing cardiac disease.
Hot flushes affect the large majority of patients on androgen or oestrogen deprivation, and are the most commonly reported effect in every indication.
Depression and cognitive difficulty are reported across indications and populations, including in paediatric use.
Can cause fetal harm; pregnancy must be excluded before starting and non-hormonal contraception used, since ovulation can occur before full suppression.
The gel-based depot formulations produce local reactions more often than the microsphere ones.
Unproven — inference onlyExtrapolated from a known mechanism, receptor profile, or adjacent compound class. Biologically plausible but not directly demonstrated for this compound in this context.
Testosterone recovery after prolonged androgen deprivation can be slow and, in older men, incomplete. Duration is a determinant.
Muscle loss on androgen deprivation is real and contributes to falls and fracture alongside the bone effect. Resistance training is the countermeasure with actual evidence.
Bone density accrual and other long-term outcomes in children treated for precocious puberty continue to be followed. The height benefit is established; the full long-term picture is still accumulating.
Uncontrolled reportsAggregated from research-community logs, forums, vendor literature and self-reported experience. Uncontrolled, unverified, subject to placebo, polypharmacy and product-purity confounds. Lowest evidentiary weight.
The universal complaint across every indication.
Consistently described and frequently underestimated before starting.
Fat gain with muscle loss is the typical pattern reported.
Frequently mentioned, particularly in the first months.
Figures below are documented, not recommended. Study ranges come from published protocols in the stated model; grey-market ranges are what the research community reports using and carry no safety validation of any kind.
Highest confidenceReported in peer-reviewed literature, registered clinical trials, or regulatory filings. Note the model: much peptide literature is in vitro or rodent work, not human trial data.
Doses and intervals are formulation-specific and not interchangeable — the microsphere intramuscular depots, the polymer subcutaneous gels and the ready-to-use suspensions each have their own strengths and schedules defined in their labels.
Where flare would be dangerous, an antiandrogen is started before the first depot and continued for several weeks, or a GnRH antagonist is used instead.
Low-dose hormonal add-back is standard for courses beyond six months, limiting bone loss and vasomotor symptoms without abolishing the therapeutic effect.
Suppression is confirmed by stimulated LH testing and by clinical assessment of pubertal progression, not assumed from the dose.
| Aspect | Detail | Note |
|---|---|---|
| Depot intervals | 1, 3, 4 or 6 months | Formulation-specific, not interchangeable |
| Time to castrate levels | ~2–4 weeks | Preceded by the flare |
| Flare window | First 1–3 weeks | Antiandrogen cover or use an antagonist |
| Bone monitoring | Densitometry, calcium, vitamin D | Long-term use |
| Endometriosis courses | Add-back beyond ~6 months | Limits bone loss and vasomotor symptoms |
| Paediatric | Weight-based, biochemically confirmed | Stimulated LH testing |
| Pregnancy | Contraindicated | Exclude before starting |
Unproven — inference onlyExtrapolated from a known mechanism, receptor profile, or adjacent compound class. Biologically plausible but not directly demonstrated for this compound in this context.
Cumulative bone, metabolic and cardiovascular consequences scale with time on treatment, which is what intermittent schedules were designed to address.
Uncontrolled reportsAggregated from research-community logs, forums, vendor literature and self-reported experience. Uncontrolled, unverified, subject to placebo, polypharmacy and product-purity confounds. Lowest evidentiary weight.
This is a depot that produces chemical castration for months at a time and cannot be reversed once administered. There is no version of unsupervised use that this site would document.
Combination effects. Almost no peptide combination has been studied as a combination in humans; stack logic is overwhelmingly mechanistic inference and community practice. Each linked compound has its own page.
Highest confidenceReported in peer-reviewed literature, registered clinical trials, or regulatory filings. Note the model: much peptide literature is in vitro or rodent work, not human trial data.
Combined androgen blockade, and subsequently the addition of abiraterone, enzalutamide, apalutamide or docetaxel to androgen deprivation, are supported by randomised survival data. Androgen deprivation is the backbone rather than the whole treatment.
Randomised trials support adding androgen deprivation to radiotherapy, with survival benefit that neither achieves alone.
Denosumab, bisphosphonates and — where fracture risk is high — anabolic therapy are used to counter treatment-induced bone loss.
Unproven — inference onlyExtrapolated from a known mechanism, receptor profile, or adjacent compound class. Biologically plausible but not directly demonstrated for this compound in this context.
Kisspeptin sits upstream of GnRH and switches the axis on; continuous leuprolide switches it off. Reading the two pages together is the shortest route to understanding how the reproductive axis is actually controlled.
Structured resistance exercise during androgen deprivation has trial support for preserving lean mass and function, and is under-prescribed.
GnRH analogues are used in assisted reproduction — but as short protocols exploiting the flare, or as antagonists preventing premature LH surge. Continuous depot suppression is the opposite intent.
Uncontrolled reportsAggregated from research-community logs, forums, vendor literature and self-reported experience. Uncontrolled, unverified, subject to placebo, polypharmacy and product-purity confounds. Lowest evidentiary weight.
Patients who maintain resistance training through androgen deprivation consistently report better function, which matches the trial evidence.
Whole schedules — dosing, titration, cycle length, and off-time — as documented in trials, as proposed from mechanism, and as circulated in the research community. Reproduced for study and comparison only.
Highest confidenceReported in peer-reviewed literature, registered clinical trials, or regulatory filings. Note the model: much peptide literature is in vitro or rodent work, not human trial data.
Antiandrogen started before the first depot and continued through the flare window in patients with metastatic disease at risk of cord compression or obstruction.
Depot with low-dose hormonal add-back for courses beyond six months, with bone density assessment for repeat or extended courses.
Suppression confirmed biochemically, growth velocity and bone age followed, and treatment discontinued at an age-appropriate point to allow puberty to resume.
Unproven — inference onlyExtrapolated from a known mechanism, receptor profile, or adjacent compound class. Biologically plausible but not directly demonstrated for this compound in this context.
Densitometry before starting long-term suppression and at intervals thereafter is the standard reasoning, given how predictable the bone effect is.
Uncontrolled reportsAggregated from research-community logs, forums, vendor literature and self-reported experience. Uncontrolled, unverified, subject to placebo, polypharmacy and product-purity confounds. Lowest evidentiary weight.
Patients describe planning around injection dates and around the symptom pattern that follows them.
The approved indications are covered above. This section covers the off-label uses, the consequence that outlasts treatment, and the principle this drug demonstrates more cleanly than anything else in the library.
Approved for advanced prostate cancer, endometriosis, uterine fibroids and central precocious puberty. Contraindicated in pregnancy — ovulation can occur before suppression is complete, so non-hormonal contraception is required from the outset.
Pathophysiology
GnRH is released in pulses roughly every 60 to 120 minutes, and the pituitary responds to the pattern rather than to the hormone.
Mechanistic rationale
Flatten the pattern into a continuous signal and the axis shuts down. That is not a side effect of leuprolide — it is the entire therapeutic strategy. The same principle explains why no-DAC CJC-1295 is preferred over the DAC form, why teriparatide builds bone while continuous parathyroid hormone destroys it, and why kisspeptin infusions are not the same as a subcutaneous bolus. Four compounds, one principle, and this is where it is used deliberately.
Community reports
The principle is under-appreciated across community protocols, where dosing frequency is usually treated as a convenience question.
Components carrying the argument: GnRH receptor downregulation
Pathophysiology
Sustained hypogonadism causes progressive bone mineral density loss and increases fracture risk, in both sexes.
Mechanistic rationale
This is the predictable long-term cost of androgen or oestrogen deprivation, and it accumulates with time on treatment. Densitometry, calcium and vitamin D, and antiresorptive or anabolic therapy where indicated are part of management rather than optional additions. In endometriosis, hormonal add-back exists specifically to limit it. Resistance training addresses the accompanying muscle loss and is under-prescribed.
Community reports
Patients frequently describe the vasomotor and fatigue effects and are less often told about the bone trajectory, which is the one that matters over years.
Components carrying the argument: Sex steroid deprivation
Pathophysiology
GnRH analogues pause pubertal progression reversibly; separately, ovarian suppression during gonadotoxic chemotherapy has been studied for preserving ovarian function.
Mechanistic rationale
Pubertal suppression is established practice in specialist gender services, with a developing and contested evidence base that belongs in a clinical consultation rather than on a reference page. Ovarian protection during chemotherapy has mixed randomised results and continuing disagreement about effect size.
Community reports
Both are specialist-supervised uses. Neither is a self-directed application.
Components carrying the argument: Axis suppression
| Question | Position |
|---|---|
| Why continuous dosing? | To shut the axis down — the strategy, not a flaw |
| Same principle elsewhere | CJC-1295 DAC, teriparatide, kisspeptin |
| Long-term cost | Bone density loss — accumulates with duration |
| Endometriosis courses | Add-back beyond ~6 months |
| Flare | First 1–3 weeks — antiandrogen cover or use an antagonist |
| Pregnancy | Contraindicated |
For advanced prostate cancer: androgen deprivation as the backbone, with abiraterone, enzalutamide, apalutamide or docetaxel added on randomised survival data, plus bone-protective therapy and resistance training during treatment. For endometriosis: hormonal contraceptives, progestins, GnRH analogues with add-back, and surgery in selected cases. For precocious puberty: specialist paediatric endocrinology with biochemical confirmation of suppression.
Physical-chemistry reference for laboratory handling of the lyophilised material. Reproduced so that stability and concentration mathematics can be studied — see the calculator for the arithmetic and the reconstitution guide for sterile technique.
Formulation-dependent and performed by a healthcare professional. The microsphere depots are reconstituted with a supplied diluent immediately before intramuscular injection; the polymer gel systems are mixed between two coupled syringes; ready-to-use suspensions require no preparation. This site publishes no reconstitution arithmetic for any of them.
Formulation-specific. Some depot kits are stored at room temperature, others refrigerated and allowed to warm before mixing. Follow the individual product label — the presentations differ more than they appear to.
Supplied as depot kits at strengths matched to their dosing interval, plus a daily subcutaneous injection formulation used in limited settings.
Reconstituted depot must be administered immediately; the polymer systems begin to set on contact with tissue fluid and cannot be held or divided.
Regulatory status changes and differs by country. This is a summary for orientation, not legal advice — check your own jurisdiction.
Approved prescription medicine. Licensed as Lupron Depot, Eligard, Camcevi and others for palliative treatment of advanced prostate cancer, management of endometriosis, preoperative treatment of anaemia associated with uterine fibroids, and central precocious puberty in children.
Contraindicated in pregnancy. Ovulation and conception can occur before suppression is complete, so non-hormonal contraception is required from the outset in anyone who could become pregnant.
Related approved agents: goserelin and triptorelin are GnRH agonists with the same flare behaviour; degarelix (injectable) and relugolix (oral) are antagonists producing suppression without a flare; cetrorelix and ganirelix are short-acting antagonists used in assisted reproduction. No legitimate unlicensed supply of any of them exists.
Regulatory and trial claims re-checked against primary sources on 16 August 2026. Checked: approved depot products and indications unchanged. Approvals, trial readouts and compounding decisions move faster than anything else on this page — a date here means someone looked, not that nothing has changed since.
GnRH agonists and antagonists are addressed under the WADA Prohibited List in the context of hormone and metabolic modulation. Verify against the current list.
Links resolve to PubMed records, trial registries, publisher pages or primary documents. Where a body of work rather than a single paper is cited, the link opens a PubMed query so the full result set — including newer papers than this page — can be reviewed. Verify every claim against the primary source before relying on it.
For educational and research reference only. Nothing on this site is medical advice, a recommendation, or an instruction to administer any substance to a human being. Every figure on this page is a record of what has been reported, not a recommendation. Full disclaimer.
