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This is an approved / prescription medicine. Do not use without a prescription and medical supervision.

EMA-approvedaka Trelstar, Decapeptyl

Triptorelin — Complete Research Guide (2026)

Last updated 2026-06-30

TL;DR

Triptorelin (also known as Trelstar) is a peptide catalogued under Sexual Health (GnRH agonist). It is described as: GnRH receptor agonist. Documented context: Prostate cancer. Neutral reference entry; EU status: EU-approved prescription medicine.

What is Triptorelin?

Triptorelin (triptorelin pamoate/embonate; brands include Trelstar, Decapeptyl, Triptodur) is a long-acting GnRH-agonist analog given as a depot injection.

It is an approved human therapeutic for advanced prostate cancer and central precocious puberty in the US, with broader European approvals including endometriosis, uterine fibroids, and assisted-reproduction protocols.

Evidence level is high, with randomized comparative trials in prostate cancer and controlled data in endometriosis and precocious puberty.

How does Triptorelin work?

Sustained GnRH-receptor stimulation causes initial gonadotropin release followed by pituitary desensitization, suppressing LH and FSH.

This lowers testosterone (men) or estradiol (women) to castrate or postmenopausal ranges, reducing hormone-driven disease activity.

What does the research say about Triptorelin?

  • Triptorelin pamoate reliably lowers testosterone to castrate levels in advanced prostate cancer, comparable to leuprolide. [1]
  • Triptorelin depot suppresses the HPG axis and halts pubertal progression in children with central precocious puberty. [2]
  • In endometriosis, triptorelin suppresses estradiol and reduces associated pelvic pain in randomized trials. [3]

Clinical research & studies

The references below are the primary sources cited throughout this guide. Each links directly to PubMed or the regulator. Where evidence is preclinical (animal or in-vitro), that is stated rather than implied.

  • [1] Comparative efficacy of triptorelin pamoate and leuprolide acetate in men with advanced prostate cancer — Heyns CF et al., BJU International 2003. (Randomized controlled trial)
  • [2] Triptorelin depot for the treatment of children 2 years and older with central precocious puberty — Bertelloni S et al., Expert Review of Clinical Pharmacology 2018. (Review)
  • [3] Assessment of Two Formulations of Triptorelin in Chinese Patients with Endometriosis: A Phase 3, Randomized Controlled Trial — Li X et al., Advances in Therapy 2022. (Randomized controlled trial)
  • [4] A randomized study comparing triptorelin or expectant management following conservative laparoscopic surgery for symptomatic stage III-IV endometriosis — Loverro G et al., European Journal of Obstetrics, Gynecology, and Reproductive Biology 2008. (Randomized controlled trial)
  • [5] Letrozole and norethisterone acetate versus letrozole and triptorelin in the treatment of endometriosis related pain symptoms: a randomized controlled trial — Ferrero S et al., Reproductive Biology and Endocrinology 2011. (Randomized controlled trial)

Dosing context

This is not medical advice or a usage recommendation. Dosing figures are reported research context only, cited from the published literature.

Triptorelin is given as clinician-administered depot injections in 1-, 3-, or 6-month formulations, with the specific product and dose selected by indication (for example a 6-month pediatric depot for precocious puberty).

This is context only, not a dosing recommendation; regimens must be individualized and prescribed by a qualified clinician.

Side effects & safety profile

Consistent with the class, therapy begins with a transient testosterone/estradiol flare that can briefly worsen prostate-cancer symptoms before hormone levels fall.

Main adverse effects stem from hypogonadism: hot flushes and vasomotor symptoms and, over time, bone mineral density loss; androgen-deprivation therapy in men also carries cardiometabolic considerations.

It is prescription-only, clinician-administered, and contraindicated in pregnancy.

Stacking & combinations

In prostate cancer a short anti-androgen course is co-administered at initiation to blunt the testosterone flare; in gynecologic use, estrogen/progestin add-back can limit bone loss and vasomotor symptoms during extended treatment.

Finding Triptorelin vendors

Finding Triptorelin vendors

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Frequently asked questions

Advanced prostate cancer and central precocious puberty in the US, with additional European approvals for endometriosis, uterine fibroids, and assisted reproduction.

References

  1. [1] Comparative efficacy of triptorelin pamoate and leuprolide acetate in men with advanced prostate cancer — Heyns CF et al., BJU International 2003. PMID: 12887472. View sourceStudy: Randomized controlled trialTriptorelin pamoate achieved and maintained castrate testosterone levels comparable to leuprolide acetate.
  2. [2] Triptorelin depot for the treatment of children 2 years and older with central precocious puberty — Bertelloni S et al., Expert Review of Clinical Pharmacology 2018. PMID: 29957076. View sourceStudy: ReviewTriptorelin depot effectively suppresses the HPG axis and arrests pubertal progression in central precocious puberty.
  3. [3] Assessment of Two Formulations of Triptorelin in Chinese Patients with Endometriosis: A Phase 3, Randomized Controlled Trial — Li X et al., Advances in Therapy 2022. PMID: 35947347. View sourceStudy: Randomized controlled trialTriptorelin formulations effectively suppressed estradiol and controlled endometriosis-associated pain.
  4. [4] A randomized study comparing triptorelin or expectant management following conservative laparoscopic surgery for symptomatic stage III-IV endometriosis — Loverro G et al., European Journal of Obstetrics, Gynecology, and Reproductive Biology 2008. PMID: 17178185. View sourceStudy: Randomized controlled trialPostoperative triptorelin reduced pain recurrence compared with expectant management after conservative surgery.
  5. [5] Letrozole and norethisterone acetate versus letrozole and triptorelin in the treatment of endometriosis related pain symptoms: a randomized controlled trial — Ferrero S et al., Reproductive Biology and Endocrinology 2011. PMID: 21693037. View sourceStudy: Randomized controlled trialBoth regimens reduced endometriosis-related pain, with the triptorelin arm showing more hypoestrogenic effects.
This article is for educational and research purposes only. Peptides discussed here are not approved for human consumption by the FDA, EMA, or equivalent regulators outside of specific clinical contexts. Always consult a licensed medical professional before any therapeutic use.