Summary
Triptorelin is a ten amino acid GnRH agonist, a lab-made version of the brain hormone that controls sex hormones, that suppresses testosterone to castrate levels (as low as after removal of the testes) after an initial flare, a brief rise, given as a 1, 3, or 6 month intramuscular depot (slow release injection into muscle). It is FDA approved as Trelstar for palliative treatment (symptom control, not cure) of advanced prostate cancer (2000) and as Triptodur for central precocious puberty, puberty that starts too early, in children 2 years and older (2017), and it is widely used abroad for endometriosis and IVF. In a 284 patient randomized trial it produced castration rates comparable to leuprolide at 9 months. It is prescription only and not compounded.
What is Triptorelin?
Triptorelin is a synthetic decapeptide GnRH (LHRH) agonist analog. It is also known as Trelstar, Triptodur, Decapeptyl, Triptorelin pamoate, Triptorelin acetate, D-Trp6-LHRH.
How does it work?
Triptorelin is a GnRH receptor agonist with a D-tryptophan substitution at position 6 that resists degradation. Continuous exposure downregulates pituitary GnRH receptors, so LH and FSH fall and testosterone or estradiol drops to castrate or prepubertal levels within 2 to 4 weeks after a brief initial surge. In children with central precocious puberty it suppresses the premature pituitary gonadal axis until treatment stops.
| Cluster | Other peptides |
|---|---|
| Routes | Intramuscular depot every 4, 12, or 24 weeks (Trelstar); Intramuscular depot every 24 weeks (Triptodur, pediatric) |
| Conditions studied | Advanced prostate cancer |
| Record | v3, draft, verified Sep 23, 2026 |
FDA-approved uses of Triptorelin
Yes. The Trelstar label (approved 2000) covers the treatment of advanced prostate cancer, and the Triptodur label (approved 2017) covers central precocious puberty, puberty that starts too early, in children 2 years and older. Both are prescription only and given as a depot (slow release) injection in a clinic. [2] [4]
What does the evidence say about Triptorelin?
Heyns 2003 (n = 284) randomized men with advanced prostate cancer to triptorelin pamoate 3.75 mg or leuprolide 7.5 mg monthly for 9 months; both achieved castrate testosterone in the large majority of patients with comparable maintenance of castration through month 9. The pediatric indication rests on an open label single arm trial in which the 6 month depot suppressed LH to prepubertal levels in most children at month 6. Other indications rely on trials conducted outside the US and summarized in the labels.
| Evidence type | Indexed studies | Participants (human) |
|---|---|---|
| Human randomized trials | 1 | 284 |
| Human observational studies | 0 | n/a |
| Animal studies | 0 | n/a |
| All indexed studies | 1 | 284 |
Human evidence
Heyns 2003: 284 men with advanced prostate cancer randomized to monthly triptorelin pamoate or leuprolide acetate for 9 months. Castrate testosterone (50 ng/dL or below) was achieved by day 29 in a slightly smaller proportion on triptorelin, but maintenance of castration through month 9 was comparable, and 9 month survival was similar. Triptodur approval was based on a 44 patient open label trial in children with central precocious puberty in which peak stimulated LH fell to prepubertal levels in the large majority by month 6 and was maintained at month 12. The endometriosis and fertility uses common in Europe rest on trials of non US formulations.
Animal evidence
Preclinical studies established GnRH receptor agonism, reversible gonadal suppression, and depot pharmacokinetics. Rat carcinogenicity studies showed pituitary adenomas at high doses, a species specific finding shared by other GnRH agonists.
Key studies
| Study | Design and population | Outcome | Grade |
|---|---|---|---|
| Comparative efficacy of triptorelin pamoate and leuprolide acetate in men with advanced prostate cancer2003 PMID 12887472 | Randomized, open label, active comparator trial, 9 monthsn = 284 Men with advanced prostate cancer | Comparable maintenance of castrate testosterone through 9 months and similar 9 month survival; triptorelin reached castration slightly more slowly by day 29 | Evidence: Human RCT evidence |
Conditions studied
| Condition | Grade | Note |
|---|---|---|
| Advanced prostate cancer | Evidence: Human RCT evidence | Comparable castration and 9 month survival to leuprolide in 284 men; FDA approved as Trelstar. |
Is Triptorelin legal in the United States?
FDA and compounding status
FDA approved as Trelstar (triptorelin pamoate) in June 2000 for palliative treatment of advanced prostate cancer, with 3 month and 6 month depots added later, and as Triptodur in June 2017 for central precocious puberty in children 2 years and older. Triptorelin is approved in Europe for endometriosis, fibroids, breast cancer, and assisted reproduction, uses that are off label in the US. Compounding is not permitted beyond patient specific needs because approved products exist.
WADA status
WADA prohibited. Athletes subject to anti-doping testing should treat this as prohibited at all times unless the current prohibited list says otherwise.
Regulatory timeline
No regulatory events recorded.
Triptorelin dose on the FDA label
Doses below are quoted from the FDA label for its approved uses, plus the doses used in the pivotal trials where noted. The prescriber sets the dose; PeptideAgent does not recommend doses or protocols.
FDA labels (DailyMed). Trelstar, advanced prostate cancer: a single intramuscular injection in either buttock of 3.75 mg every 4 weeks, 11.25 mg every 12 weeks, or 22.5 mg every 24 weeks; the strengths are not additive. Triptodur, central precocious puberty in children 2 and older: 22.5 mg as a single intramuscular injection every 24 weeks, given by a healthcare provider, with LH or sex steroid levels checked 1 to 2 months after starting.
Routes reported
| # | Route |
|---|---|
| 1 | Intramuscular depot every 4, 12, or 24 weeks (Trelstar) |
| 2 | Intramuscular depot every 24 weeks (Triptodur, pediatric) |
What are the side effects and interactions of Triptorelin?
Side effects
| # | Reported side effect |
|---|---|
| 1 | Hot flashes (the most common effect in men, over half of patients) |
| 2 | Testosterone flare in the first 1 to 2 weeks, which can worsen bone pain, ureteral obstruction, or spinal cord compression in metastatic prostate cancer |
| 3 | Erectile dysfunction, decreased libido, fatigue |
| 4 | Bone density loss with prolonged use |
| 5 | Hyperglycemia, weight gain, and increased cardiovascular risk with long term androgen deprivation |
| 6 | QT prolongation |
| 7 | Injection site pain; in children, injection site reactions and transient vaginal bleeding after the first dose |
| 8 | Anaphylaxis and pituitary apoplexy (rare) |
Interactions
| # | Interaction |
|---|---|
| 1 | QT prolonging drugs: additive risk during androgen deprivation |
| 2 | Hyperprolactinemic drugs: high prolactin reduces pituitary GnRH receptors and may blunt the effect |
| 3 | Antidiabetic drugs: glucose control may worsen and require adjustment |
| 4 | Interferes with pituitary gonadal diagnostic tests during and after treatment |
Contraindications
| # | Contraindication |
|---|---|
| 1 | Pregnancy (fetal harm) and breastfeeding |
| 2 | Hypersensitivity to triptorelin, GnRH, or other GnRH analogs |
| 3 | Use with caution where flare could cause spinal cord compression or urinary obstruction unless an antiandrogen is given |
How do people access Triptorelin legally?
Typical cost: Trelstar lists at roughly 1,500 to 2,500 USD per monthly 3.75 mg injection and roughly 4,500 to 7,000 USD for the 3 month 11.25 mg depot. Insurance and Medicare Part B typically cover it for prostate cancer; Triptodur for children is covered with prior authorization.
Verified access options
Step 1
Prescription from a urologist, oncologist, or pediatric endocrinologist, administered in clinic as a depot injection.
Step 2
Fertility clinics prescribe triptorelin off label (often imported or compounded acetate) as an IVF trigger.
Step 3
Not available through telehealth peptide clinics.
Access paths are verified against public regulatory records and prescriber licensing. We never list unlicensed vendors.
Frequently asked questions
Does triptorelin work as well as leuprolide for prostate cancer?
Comparably. In a 284 patient randomized trial, monthly triptorelin 3.75 mg and leuprolide 7.5 mg both brought testosterone to castrate levels in the large majority of men, with similar maintenance of castration and 9 month survival. Triptorelin was slightly slower to reach castration at day 29 in that trial. [1]
What are the side effects of triptorelin?
The expected effects of low testosterone: hot flashes, loss of libido, erectile dysfunction, fatigue, weight gain, and bone loss over time. A testosterone flare in the first 1 to 2 weeks can temporarily worsen bone pain or urinary obstruction in men with metastatic cancer, so an antiandrogen is often given at the start. Long term use raises diabetes and cardiovascular risk and can prolong the QT interval. [1] [2]
What is the triptorelin (Trelstar) dose on the FDA label?
Trelstar for advanced prostate cancer is one intramuscular injection of 3.75 mg every 4 weeks, 11.25 mg every 12 weeks, or 22.5 mg every 24 weeks. Triptodur for central precocious puberty is 22.5 mg every 24 weeks. A clinician gives every dose, and the strengths are not interchangeable. [2] [4]
How much does triptorelin cost?
Roughly 1,500 to 2,500 USD per monthly 3.75 mg Trelstar injection and 4,500 to 7,000 USD for the 3 month depot at list price. Insurance and Medicare Part B cover it for prostate cancer, and Triptodur is covered for precocious puberty with prior authorization. Prices were checked on the last verified date. [2]
Is triptorelin banned by WADA?
Yes for male athletes. WADA's section S2 names triptorelin among the GnRH analogs prohibited in males at all times. A therapeutic use exemption is required for medical use. [3]
Why do IVF clinics use triptorelin?
A single low dose of a GnRH agonist such as triptorelin triggers an LH surge that matures eggs before retrieval, and it lowers the risk of ovarian hyperstimulation syndrome compared with an HCG trigger. This use is off label in the US and relies on non US formulations or compounded triptorelin acetate. [2]
Triptorelin vs leuprolide vs degarelix: how do they differ?
Triptorelin and leuprolide are GnRH agonists with a testosterone flare and comparable castration rates; degarelix is a GnRH antagonist with no flare and suppression within 3 days, at the cost of frequent injection site reactions. Triptorelin has the pediatric 6 month depot; leuprolide has more formulations; degarelix is preferred when a flare would be dangerous. [1]
Decisions about starting, stopping, or combining any treatment belong with a licensed clinician who knows your history.
Sources
Numbered citations above point to these primary sources. PubMed entries link to the indexed abstract.
- [1]Heyns CF et al. Comparative efficacy of triptorelin pamoate and leuprolide acetate in men with advanced prostate cancer. BJU Int 2003PubMed 12887472, 2003
- [2]FDA prescribing information for Trelstar (triptorelin pamoate for injectable suspension), via DailyMedFDA, 2026
- [3]WADA Prohibited List, section S2 (GnRH and its analogs in males)WADA, 2026
- [4]FDA prescribing information for Triptodur (triptorelin) for extended-release injectable suspension, via DailyMedFDA, 2025
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<a href="https://peptideagent.ai/peptides/triptorelin">Triptorelin: evidence, legality, and access</a>, PeptideAgent, updated September 23, 2026.