Triptorelin is a synthetic decapeptide that mimics gonadotropin-releasing hormone (GnRH). Its structure copies natural GnRH but swaps the glycine at position 6 for D-tryptophan, which is why you'll see it written as (D-Trp6)-GnRH or D-Trp6-LHRH. That single change makes the molecule resist enzymatic breakdown and bind the pituitary receptor more tightly, so it lasts far longer than the natural hormone. It was patented in 1975 and approved for medical use in 1986, and it's sold under brand names including Decapeptyl, Trelstar, Triptodur, Diphereline, and Gonapeptyl (DrugBank; Wikipedia).
This is an approved prescription drug, not a research chemical. Nothing here is medical or dosing advice.
How it works
GnRH agonists do something that sounds backwards: a drug that ultimately suppresses sex hormones starts by raising them. After the first dose there's a transient surge in luteinizing hormone (LH), follicle-stimulating hormone (FSH), testosterone, and estradiol, sometimes called the flare. With continuous exposure the pituitary GnRH receptors down-regulate and desensitize. By roughly four weeks of therapy, LH and FSH secretion falls and sex-steroid levels drop sharply, producing what the literature calls reversible chemical (or biochemical) castration (DrugBank). Because the effect runs through the pituitary, it's used in both sexes: lowering testosterone in men, lowering estradiol in women.
What the research and approvals cover
Triptorelin is established across several indications:
- Advanced prostate cancer. As androgen-deprivation therapy, it suppresses testosterone to treat hormone-dependent prostate cancer.
- Central precocious puberty. The Triptodur formulation (22.5 mg, one intramuscular injection every 24 weeks) is approved in the U.S. for children with central precocious puberty, where it halts the premature activation of the hypothalamic-pituitary-gonadal axis (Drugs.com FDA history).
- Endometriosis and uterine fibroids. By cutting ovarian estrogen output, it's used to manage these estrogen-dependent conditions.
The endometriosis evidence is solid. A phase 3 randomized controlled trial in Chinese patients compared a 3-month depot against a 1-month formulation. At week 12, more than 98% of patients in both arms had reached chemical castration (estradiol ≤184 pmol/L): 98.6% on the 3-month version and 99.3% on the 1-month version, and the longer-acting depot was non-inferior while needing only two injections over 24 weeks instead of six (Liu et al., *Advances in Therapy*, 2022). Triptorelin is also used in assisted-reproduction protocols, where a short course controls the timing of ovulation.
Doping status
GnRH and its agonist analogues, triptorelin among them (also buserelin, goserelin, histrelin, leuprorelin, nafarelin, deslorelin), sit on the WADA Prohibited List under section S2. They are banned in males, because the initial flare stimulates endogenous testosterone. WADA has listed GnRH analogues since January 2016, and metabolites count too: anti-doping labs have characterized triptorelin urinary metabolites specifically for detection (WADA Prohibited List).
The quality angle for buyers
If you're sourcing triptorelin as a research peptide rather than a pharmacy product, identity and purity are the things a certificate of analysis (COA) should actually demonstrate, typically by mass spectrometry for identity and HPLC for purity. A peptide this well-characterized has a real reference standard to check against. peptideone aggregates third-party COAs and independent vendor ratings so you can compare what sellers publish; we don't sell it, test it, or recommend a use. Treat any non-pharmaceutical material as research-use-only and not for human consumption.