Triptorelin

In simple words

Triptorelin is an enhanced, long-acting version of the brain hormone that controls the sex glands. It is an approved drug: with continuous administration, it temporarily "switches off" sex hormone production, which is used in prostate cancer, endometriosis, and puberty that starts too early.

What this molecule is

pGlu-His-Trp-Ser-Tyr-D-Trp⁶-Leu-Arg-Pro-Gly-NH₂ — 10 aa. GnRH + Gly⁶→D-Trp⁶ substitution → affinity ×100 + resistance to proteolysis.

Why it is studied

Long-acting GnRH superagonist. FDA/EMA-approved: prostate cancer, endometriosis, uterine fibroids, central precocious puberty (CPP). Phase 3-4 meta-analyses (2022-2024). Achieves castrate testosterone levels (<50 ng/dL) more reliably than surgical castration.

How it works

Flare effect (1-2 weeks): ↑LH/FSH/testosterone. Then: continuously high concentration → GnRH-R desensitization → ↓LH/FSH → castrate testosterone levels. Reversible after discontinuation.

Doses used in studies

Studies and approved regimens used: in prostate cancer — 3.75 mg IM monthly / 11.25 mg every 3 months / 22.5 mg every 6 months; in CPP — 3.75–11.25 mg IM; in endometriosis — 3.75 mg monthly for up to 6 months.

Combined with in studies

• Antiandrogens (bicalutamide) — combined blockade in prostate cancer
• Add-back therapy — low estrogen in endometriosis
• Other GnRH agonists — NOT compatible

Level of evidence

Level A Human clinical trials. There are randomized controlled trials (RCTs), or the compound has been approved by a regulatory agency. The most reliable level. FDA/EMA-approved. Multiple RCTs. Decades of use.

Important to know

🔴 Prescription drug prescribed by an oncologist / endocrinologist / gynecologist. Requires monitoring of testosterone and BMD (risk of osteoporosis with long-term use).

Studies in PubMed

1. [Multicentre randomized trial comparing triptorelin medical castration versus surgical castration in the treatment of locally advanced or metastatic prostate cancer]. (Prog Urol, 2007)
2. Luteinizing Hormone-Releasing Hormone Agonists are Superior to Subcapsular Orchiectomy in Lowering Testosterone Levels of Men with Prostate Cancer: Results from a Randomized Clinical Trial. (J Urol, 2017)
3. Fertility of Women Treated during Childhood with Triptorelin (Depot Formulation) for Central Precocious Puberty: The PREFER Study. (Horm Res Paediatr, 2020)
4. Central precocious puberty: treatment with triptorelin 11.25 mg. (ScientificWorldJournal, 2012)
5. An Update on Triptorelin: Current Thinking on Androgen Deprivation Therapy for Prostate Cancer. (Adv Ther, 2016)
6. Triptorelin therapy for lower urinary tract symptoms (LUTS) in prostate cancer patients: A systematic meta-analysis. (BJUI Compass, 2024)