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evidence · mechanism · dose
Experimental/GnRH AgonistResearch peptide

Leuprolide

aka Lupron

Long-acting GnRH agonist used in prostate cancer, endometriosis, and precocious puberty.

Educational explainer of a research peptide. Profiles in this section deliberately omit clinical-trial citations, dosing protocols, and purchase links. Not FDA-approved as a supplement; not a recommendation to use.

Overview

Leuprolide is a nonapeptide GnRH agonist used clinically as a depot injection to suppress the HPG axis in hormone-responsive disease.

Source
  • Approved pharmaceutical
Forms
  • Depot intramuscular and subcutaneous injection

Mechanism of action

Continuous receptor stimulation desensitizes the pituitary, suppressing LH, FSH, and downstream sex steroids after an initial flare.

Pathways
  • · GnRH receptor desensitization
  • · LH and FSH suppression
  • · Gonadal steroid suppression
Hormones
  • · GnRH
  • · LH
  • · FSH
  • · Testosterone
  • · Estradiol

How it acts on the body

Leuprolide produces medical castration after an initial 1-2 week flare. In prostate cancer it suppresses androgen-driven growth; in endometriosis and uterine fibroids it suppresses estrogen-driven lesion activity; in central precocious puberty it halts premature pubertal progression.

Flare prophylaxis (e.g. with an androgen receptor antagonist in prostate cancer) is essential because rising testosterone in the first weeks can worsen disease before suppression begins.

Hormonal & endocrine impact

How this peptide is reported to shift specific hormones and signaling molecules. Directionality reflects research literature and preclinical models, not clinical prescribing data.

Projected hormonal trajectory
Illustrative curves derived from reported direction of effect. Not measured patient data.

Curves are schematic shapes (sigmoid for increases/decreases, damped oscillation for modulation/stabilization) anchored to a 100% baseline. They communicate direction and tempo of change reported in research literature — not absolute hormone concentrations.

TestosteroneDecreases
Castrate range after flare.
EstradiolDecreases
Postmenopausal range.
LH and FSHDecreases
Pituitary downregulation.

Effects on the body

Decreases
Androgen-driven prostate cancer activity
Decreases
Estrogen-driven endometriosis and fibroid activity
Decreases
Pubertal progression in CPP

Organ system effects

Endocrine

Pituitary downregulation.

Reproductive

HPG suppression.

Bones

Density loss with chronic use without add-back.

Reported effects

Drawn from preclinical research, anecdote, and small-scale clinical observation. No evidence grades are assigned — most peptides on this page lack rigorous human trials.

  • Depot dosing for convenience
  • Strong evidence base across indications

Potential side effects

Common
  • · Hot flashes
  • · Decreased libido
  • · Mood changes
Rare
  • · Injection-site reactions
Serious
  • · Tumor flare
  • · Bone loss
  • · QT prolongation with some formulations

Drug interactions

QT-prolonging agents
Caution with combinations.
moderate

Pairing context

Often combined with
  • Add-back therapy in benign indications
    Mitigates bone and vasomotor effects.
Avoid combining with
  • Pregnancy
    Contraindicated.
Important. Research peptides described here are not FDA-approved supplements. Supplement Scholar does not endorse, recommend, or link to any source for purchase. Consult a qualified clinician before considering any peptide therapy.