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Hormonal

Triptorelin

Also known as Trelstar · Triptodur · Triptorelin pamoate · Decapeptyl SR · (D-Trp6)-GnRH · CL-118532

FDA-approvedAHuman trial evidenceWhat this means

Triptorelin is a synthetic decapeptide GnRH agonist, FDA-approved (initial U.S. approval 2000) as Trelstar for advanced prostate cancer and as Triptodur for central precocious puberty in children 2 years and older.

US status
FDA-approved
Evidence
Grade A
Half-life
After intravenous bolus in healthy men, distribution and elimination follow a 3-compartment model with half-lives of about 6 minutes, 45 minutes and 3 hours; depot formulations release drug over 4 to 24 weeks 1.
Class
Gonadotropin-releasing hormone (GnRH) agonist
Studied in: Hormonal & endocrine research · Class: Kisspeptin & GnRH axis
More
Log a sample
Dosing referenceCycle-length evidence
Unbranded reference vial illustrating Triptorelin; not an actual product
Research reference, not advice. Label quotes, not a recommendation. Amiravo sells nothing; some links are referrals.Read the full notice

Key takeaways

  • Triptorelin is a GnRH agonist approved as Trelstar for advanced prostate cancer and as Triptodur for central precocious puberty 1,2.
  • All three Trelstar strengths achieved castration by day 29 in 91-98% of men in label trials 1.
  • The initial testosterone surge can cause tumor flare; labeled risks also include metabolic changes, cardiovascular disease in men, QT prolongation, convulsions and severe cutaneous reactions 1.
  • In children, warnings include the initial rise in gonadotropins, psychiatric events, convulsions and pseudotumor cerebri 2.
  • WADA's 2026 list names triptorelin under S2.2.1 (testosterone-stimulating peptides in males), prohibited at all times 5.

Development stage

Where Triptorelin sits between laboratory work and regulatory approval.

  1. Preclinical
  2. Phase 1
  3. Phase 2
  4. Phase 3
  5. Approved (current)

Stage comes from the regulatory record and ClinicalTrials.gov studies naming the compound (for compounds approved nowhere, only completed trials or trials with posted results count) (checked 2026-10-24). A registered trial is not a result.

Mechanism of action

Triptorelin is a synthetic decapeptide GnRH agonist 1.

Potency

  • In vitro it was 100-fold more active than native GnRH in stimulating LH release from dispersed rat pituitary cells and 20-fold more active in displacing labeled GnRH from pituitary receptors 1.
  • In animals, triptorelin pamoate had 13-fold higher LH-releasing and 21-fold higher FSH-releasing activity than native GnRH 1.

Biphasic effect

The first dose produces a transient surge in LH, FSH, testosterone and estradiol; after 2 to 4 weeks of continuous exposure, LH and FSH fall and testosterone reaches levels typical of surgical castration. Effects are usually reversible after cessation 1.

Molecular structure

PubChem CID 25074470 ↗
2D chemical structure of Triptorelin

2D depiction generated from the PubChem record. Depictions are schematic and do not show salt form, counter-ions or conformation.

Formula
C64H82N18O13
Molecular weight
1311.4 g/mol
CAS
57773-63-4
InChIKey
VXKHXGOKWPXYNA-PGBVPBMZSA-N

Research overview

Human research

Randomized active-controlled and single-arm trials in men with advanced prostate cancer evaluated achievement and maintenance of castrate testosterone 1,4. A single-arm 12-month study in 44 children with CPP supported the Triptodur indication 2.

Animal research

In animal studies, triptorelin pamoate had higher LH- and FSH-releasing activity than native GnRH; in pregnant rats it caused maternal and embryo-fetal toxicity, including pregnancy loss 1.

In-vitro research

In dispersed rat pituitary cell cultures, triptorelin was 100-fold more active than native GnRH in stimulating LH release and 20-fold more active in receptor displacement 1.

Key studies

  1. Heyns et al., BJU Int (2003)
    Randomized comparison with leuprolide 7.5 mg, monthly for 9 injections
    Model: Humans (284 men with advanced prostate cancer)

    Castration at day 29: 91.2% versus 99.3%; at day 57: 97.7% versus 97.1%; cumulative maintenance 96.2% versus 91.2%; 9-month survival 97.0% versus 90.5% 4.

  2. Trelstar prescribing information, Section 14 (11.25 mg) (2026)
    Randomized active-controlled trial versus Trelstar 3.75 mg
    Model: Humans (346 men with advanced prostate cancer)

    Castration by day 29 in 97.7% and maintained from day 57 through day 253 in 94.4% 1.

  3. Trelstar prescribing information, Section 14 (22.5 mg) (2026)
    Non-comparative trial, two doses every 24 weeks
    Model: Humans (120 men with advanced prostate cancer)

    Castration by day 29 in 97.5%; maintained from day 57 to day 337 in 93.3% 1.

  4. Triptodur prescribing information, Section 14 (2025)
    Single-arm open-label study, 12 months
    Model: Humans (44 children aged 2-9 with CPP)

    At least 93% had prepubertal stimulated LH at every timepoint; 95% showed no increase in bone age/chronological age ratio at month 12 2.

Dosing as stated on the FDA label

Quoted from the prescribing information for reference. Prescribing decisions belong to a licensed clinician; this is not a recommendation or instruction for use.

Full dosing reference, study durations and vial arithmetic →
  • Advanced prostate cancer (Trelstar): a single intramuscular injection of 3.75 mg every 4 weeks, 11.25 mg every 12 weeks, or 22.5 mg every 24 weeks; strengths are not additive and are chosen by desired schedule 1.
  • Central precocious puberty (Triptodur): 22.5 mg as a single intramuscular injection once every 24 weeks, discontinued at the appropriate age for puberty onset 2.
  • Reconstitution and administration instructions are in the labels and are not reproduced here 1,2.

Published adverse-event data

Reported in the cited trials or product labels. Frequencies apply to the stated population and do not transfer to other settings.

Label warnings

  • Contraindicated with known hypersensitivity to triptorelin, product components, other GnRH agonists or GnRH; anaphylactic shock and angioedema have been reported 1. 1
  • Tumor flare from the transient testosterone increase, including bone pain, neuropathy, hematuria and urethral or bladder outlet obstruction; spinal cord compression has occurred 1. 1
  • Metabolic changes (hyperglycemia, diabetes, hyperlipidemia), increased risk of MI, sudden cardiac death and stroke in men, convulsions, severe cutaneous adverse reactions and QT/QTc prolongation 1. 1
  • Embryo-fetal toxicity based on animal studies and mechanism of action 1. 1
  • Pediatric (Triptodur): initial rise of gonadotropins and sex steroids, psychiatric events, convulsions, SCARs and pseudotumor cerebri 2. 2
  • Hot flush
    58.6% (82/140)
    Men with advanced prostate cancer, Trelstar 3.75 mg 1 · Treatment-related per investigator
  • Skeletal pain
    12.1%
    Same trial 1 · Treatment-related per investigator
  • Impotence
    7.1%
    Same trial 1 · Treatment-related per investigator
  • Headache
    5.0%
    Same trial 1 · Treatment-related per investigator
  • Injection site pain
    45% (children, after injection); 3.6% (men, Trelstar 3.75 mg)
    Children with CPP (n=44); men with prostate cancer 2 · Local
  • Headache and nasopharyngitis
    13.6% each
    Children with CPP (n=44), 12 months 2 · Not graded

Emerging safety signals

  • Subjects with renal or hepatic impairment had 2- to 4-fold higher exposure than young healthy males 1. 1 (2026)
  • Diagnostic tests of pituitary-gonadal function during and after treatment may be misleading because of axis suppression 1. 1 (2026)

What is not known: The label describes cardiovascular risk with GnRH agonists in men as appearing low based on reported odds ratios, without a precise estimate 1. The Triptodur indication rests on a single-arm study of 44 children 2.

Background viewing

We haven't found a clinician video focused on Triptorelin yet. Meanwhile, this widely watched talk covers the science of aging in general. It does not discuss Triptorelin.

David Sinclair, PhD (Harvard Medical School) on the biology of aging
The Diary Of A CEO · 6.9M views · 2026

These creators are not affiliated with Amiravo and do not endorse Amiravo or any product linked on this site. Nothing here is medical advice. Video views counted on YouTube as of Oct 24, 2026.

Regulatory status

Status
FDA-approved (initial U.S. approval 2000). As of 2026-10-24 Drugs@FDA lists Trelstar 3.75 mg, 11.25 mg and 22.5 mg and Triptodur 22.5 mg with prescription marketing status 1,2,3.
United States (FDA)
FDA-approved (initial U.S. approval 2000): Trelstar (NDA 020715, 021288, 022437) and Triptodur (NDA 208956), all listed with prescription marketing status as of 2026-10-24 1,2,3.
Sport (WADA)
The WADA 2026 Prohibited List names triptorelin among GnRH agonist analogues under S2.2.1 (testosterone-stimulating peptides in males); S2 is prohibited at all times 5.

Status varies by country and changes over time. How we describe regulatory status.

Quality and testing notes

A certificate of analysis for triptorelin material would be expected to show HPLC purity, identity by mass spectrometry against the free-base molecular weight (PubChem 1311.4 g/mol), D-Trp6 stereochemistry and C-terminal glycinamide, salt form (acetate or pamoate), net peptide content and endotoxin level [1, 6].

How purity testing works · Reading a certificate of analysis

Check a Triptorelin certificate of analysis against its expected mass (1,311.4 Da)

Storage and handling

The Trelstar label directs storage at 20-25°C, not frozen [1].

Frequently asked questions

What is triptorelin?
A synthetic decapeptide GnRH agonist with D-tryptophan at position 6 1,6.
What is it approved for?
Advanced prostate cancer (Trelstar) and central precocious puberty in children 2 years and older (Triptodur) 1,2.
How does it lower testosterone if it is an agonist?
An initial surge in LH and FSH is followed by sustained suppression after 2 to 4 weeks of continuous exposure 1.
How does it compare with leuprolide?
In a 284-man randomized trial, triptorelin reached castration more slowly at day 29 but maintained it equivalently 4.
What are common adverse reactions in men?
Hot flush, skeletal pain, impotence and headache with Trelstar 3.75 mg 1.
Are the strengths interchangeable?
No. The label states the strengths are not additive because of different release characteristics 1.
Is it banned in sport?
WADA's 2026 list names triptorelin under S2.2.1 for males, prohibited at all times 5.

Latest indexed research

Search all studies on Triptorelin (PubMed, Europe PMC, ClinicalTrials.gov)

Listed by publication type from the index record. Inclusion is not an endorsement; open the source to read the findings.

Revision history

Meaningful changes to this entry, with dates and sources. Last reviewed Oct 24, 2026. Typo and layout fixes are not listed.

  • New section· entryOct 24, 2026

    New research reference added: Triptorelin.

Last reviewed October 24, 2026 by the Amiravo editorial team.

Read our editorial policy · Report an error on this page

Need the math?

Laboratory arithmetic with every formula shown.

For research use only. Not for human or veterinary use. Not a drug, food, or dietary supplement. This page is educational and is not medical advice.

Unbranded reference vial illustrating Triptorelin; not an actual product

Unbranded reference image. Amiravo does not produce, supply or sell this compound.

Specifications

Molecular formula
C64H82N18O13
Molecular weight
1,311.4 g/mol
CAS number
57773-63-4
PubChem CID
25074470
FDA UNII
9081Y98W2V
ChEMBL
CHEMBL1201334
DrugBank
DB06825
Sequence
pGlu-His-Trp-Ser-Tyr-D-Trp-Leu-Arg-Pro-Gly-NH2
Type
Single compound

Identifiers from PubChem. Verify against the supplier’s documentation for your lot.

Research stats

How much has been published, not how good it is.

PubMed records
1,005
Indexed as human research
755
Animal-only research
79
Randomized controlled trials
173
Registered trials
298
Trials with posted results
48
FDA adverse-event reports (FAERS)
4,036
NIH-funded projects naming it
20
2006: 292007: 232008: 332009: 322010: 322011: 322012: 372013: 232014: 282015: 512016: 392017: 322018: 482019: 412020: 422021: 422022: 412023: 372024: 502025: 512026: 3520062026
PubMed records per year (current year is partial).

Counts from title/abstract searches of PubMed, ClinicalTrials.gov, openFDA and NIH RePORTER, checked 2026-10-24. Names shared with other substances can inflate counts. FAERS reports are spontaneous and do not establish cause. Funding shows interest, not evidence. Method

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