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Triptorelin

moderate risk

Also: Trelstar · Decapeptyl · GnRH agonist

Strong Evidence FDA Approved

Triptorelin is an FDA-approved GnRH agonist that paradoxically causes chemical castration through pituitary desensitization with continuous dosing. Approved for prostate cancer, endometriosis, and precocious puberty. Also used off-label post-cycle in performance enhancement contexts.

Molecular Weight
1311.5 Da
Formula
C64H82N18O13
Common Dosing
3.75 mg IM monthly; 11.25 mg IM every 3 months; 22.5 mg IM every 6 months (depot formulations)
Category
therapeutic
Last Reviewed
2025-01-15

Reported Benefits

Prostate cancer (androgen suppression)

Strong Evidence 145 studies

FDA-approved standard of care for advanced prostate cancer; achieves castrate testosterone levels.

Endometriosis

Strong Evidence 67 studies

Reduces endometriosis lesion size and pain scores via estrogen suppression.

PCT (off-label)

Preliminary 5 studies

Used in performance enhancement PCT to restart HPG axis; limited formal study but mechanistically rational.

Mechanism of Action

Long-acting GnRH agonist — initial stimulation followed by sustained pituitary GnRH receptor downregulation, profoundly suppressing LH, FSH, testosterone/estrogen to castrate levels.

Key Clinical Studies

Crawford et al. (1989)

Phase III RCT · n=244

PubMed →

Castrate testosterone levels in advanced prostate cancer; comparable to orchiectomy

Paradoxical Mechanism

GnRH agonists cause hypogonadism by flooding the pituitary with continuous stimulation — the opposite of pulsatile physiologic GnRH. This downregulation is the therapeutic mechanism in prostate cancer and endometriosis.

Off-Label PCT Use

In performance enhancement contexts, triptorelin has been used to rapidly restart the HPG axis post-anabolic steroid cycle. This use is not FDA-approved and carries significant risk due to the biphasic agonist/antagonist nature of the compound.

Regulatory Status

FDA Approved

FDA approved (Trelstar) for prostate cancer and other indications

Safety Profile

Side Effects

  • •Hot flashes
  • •Bone density loss
  • •Sexual dysfunction
  • •Fatigue
  • •Initial testosterone surge ('flare effect')

Contraindications

  • •Pregnancy
  • •Hormone-sensitive conditions not being treated

Drug Interactions

  • •QT-prolonging drugs
  • •Sex steroid supplements

Primary Uses

Prostate cancerEndometriosisUterine fibroidsPrecocious puberty

Related Peptides

gonadorelinkisspeptin-10

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Disclaimer: This information is for educational and research purposes only. Not medical advice. Consult a qualified healthcare provider before using any compound.