Triptorelin is a synthetic GnRH agonist decapeptide analog (MW ~1311.4 g/mol) with a D-Trp substitution at position 6 of native GnRH. It is FDA-approved for the palliative treatment of advanced prostate cancer (Trelstar) and for central precocious puberty (Triptodur). Available as intramuscular depot injections in 1-month (3.75 mg), 3-month (11.25 mg), and 6-month (22.5 mg) formulations. Like other GnRH agonists, it operates through initial pituitary stimulation followed by receptor downregulation and gonadotropin suppression.
Category: Reproductive / Hormonal. Evidence rating: A (strong human clinical data).
Clinical status: FDA-approved (Trelstar for advanced prostate cancer; Triptodur for central precocious puberty)
Triptorelin is a potent GnRH agonist with approximately 100-fold greater potency than native GnRH due to the D-Trp6 substitution, which confers resistance to enzymatic degradation and enhanced receptor binding. The "flare then suppression" mechanism applies: initial doses stimulate pituitary…
Safety considerations: Hot flashes (58-73% of prostate cancer patients); Skeletal pain and disease flare during initial 1-2 weeks; Erectile dysfunction and decreased libido.
Reviewed by the PeptideAtlas Editorial Team. Last reviewed: 2026-08-12.
Related peptides: Kisspeptin, Gonadorelin, Oxytocin.
Compare: Triptorelin vs Kisspeptin, Triptorelin vs Gonadorelin, Triptorelin vs Oxytocin.
Triptorelin and leuprolide are both GnRH agonists with comparable efficacy for achieving castrate testosterone levels in prostate cancer. Head-to-head trials show non-inferiority. The choice is often based on formulation preference, available depot durations, and institutional formulary.
Like all GnRH agonists, triptorelin causes a transient increase in testosterone during the first 1-2 weeks of treatment. This can temporarily worsen prostate cancer symptoms (bone pain, urinary obstruction). Anti-androgen therapy (e.g., bicalutamide) is typically started before or with the first injection to block flare effects.
Yes, in Europe and other regions, triptorelin is widely used for endometriosis, uterine fibroids, IVF pituitary suppression, and central precocious puberty. In the US, it is FDA-approved for prostate cancer and central precocious puberty.