CalcMyPeptide
Healing & RecoveryAlso known as: Trelstar, Decapeptyl, GnRH Agonist

Triptorelin

Triptorelin (Decapeptyl) is a synthetic, aggressively potent agonist of Gonadotropin-Releasing Hormone (GnRH). In mainstream medicine, it is used in depot forms to chemically castrate prostate cancer patients via receptor burnout. However, in the elite strata of endocrinology and intensive Post-Cycle Therapy (PCT), a single, hyper-precise micro-dose (100mcg) is deployed. This unique, single-shot protocol serves as an absolute "defibrillator" for the Hypothalamic-Pituitary-Testicular Axis (HPTA), violently kickstarting endogenous testosterone production after years of profound suppression from anabolic steroids.

Reviewed by CalcMyPeptide Editorial Team
Last updated: April 2026Evidence: Moderate2 peer-reviewed citations

Quick Stats

Half-Life~3 hours (SC)
Dose Range100 mcg (single dose PCT)
FrequencySingle dose (PCT)
Vial Sizes0.1 mg
BioavailabilitySubcutaneous injection
Year Developed1986

Scientific Data

Molecular Formula
C64H82N18O13
Molecular Weight
1311.45 g/mol
CAS Number
PubChem ID

Mechanism of Action

Triptorelin is a synthetic GnRH agonist decapeptide used in post-cycle therapy (PCT) to restart the hypothalamic-pituitary-testicular axis (HPTA) after anabolic steroid or SARM suppression.

A single low-dose (100 mcg) subcutaneous injection causes a powerful LH/FSH surge by transiently overstimulating GnRH receptors. This pituitary restart can restore natural testosterone production within 72-96 hours. At higher or continuous doses, triptorelin paradoxically suppresses the HPTA via GnRH receptor desensitization — the same mechanism exploited clinically (Trelstar) for prostate cancer treatment. This dual agonist/antagonist dose-dependency makes triptorelin unique and requires precise single-dose administration for PCT.

Source: PMID: 15483224

Background & History

Triptorelin is a synthetic GnRH decapeptide analog (D-Trp6 substitution) used medically as a depot injection for prostate cancer (via GnRH receptor desensitization causing chemical castration), endometriosis, uterine fibroids, and precocious puberty. In performance medicine, it is used off-label in single low-dose administration (100 mcg) to trigger a massive LH surge for HPG axis restart ("triptorelin PCT") after suppression from androgens or other hormones.

Research Use Cases

  • Post-cycle therapy: single low-dose HPG axis restart after prolonged androgen suppression
  • Prostate cancer treatment (depot formulation)
  • Endometriosis and uterine fibroid management (depot)

Dosing Protocol

Typical Dose100 mcg (single dose PCT)
FrequencySingle dose (PCT)
Half-Life~3-5 hours
Common Vial Sizes0.1 mg

Dosing Protocols

PCT Protocol (ONE dose ONLY)

Dose
100 mcg
Frequency
ONE single injection (SC) — NEVER repeated
Note: CRITICAL: Use ONLY a single 100 mcg dose. A second dose will suppress the axis. This is not a daily peptide. Follow HCG + SERM support protocol post-injection.

Body-Weight Dosing Reference

Estimated doses extrapolated from the published research range of 100100 mcg/day (referenced to 70 kg / 154 lb). These are approximations — consult a qualified healthcare provider for personalised guidance.

WeightLowTargetHigh
120 lb(54 kg)77 mcg77 mcg77 mcg
140 lb(63 kg)90 mcg90 mcg90 mcg
160 lb(73 kg)104 mcg104 mcg104 mcg
180 lb(82 kg)117 mcg117 mcg117 mcg
200 lb(91 kg)130 mcg130 mcg130 mcg
220 lb(100 kg)143 mcg143 mcg143 mcg
250 lb(113 kg)161 mcg161 mcg161 mcg

💉 For exact syringe units based on your vial concentration, use the Triptorelin Reconstitution Calculator →

Administration

Route
Single subcutaneous injection
Timing
Any time — single administration only.
Fasting Required?
No — food timing not critical

Expected Timeline

1-4 hours post-injection
Massive LH/FSH surge from pituitary overstimulation.
72-96 hours
Testosterone production may resume. Monitor serum testosterone to confirm restart.
Week 2-6
Continue SERM support (Nolvadex/Clomid) to maintain HPTA recovery momentum.

Who Is It For?

Post-Cycle Therapy (PCT)

Moderate

Fastest HPTA restart available. One 100 mcg dose can restore testosterone in 72-96 hours. Precision required.

Reconstitution Example

Vial
0.1 mg
Water
1 mL
Concentration
0.1 mg/mL
Per Unit (100u syringe)
1 mcg
Dose of 100 mcg = 100 units on a 100-unit insulin syringe

Safety & Considerations

FDA-approved (Trelstar) at high doses for prostate cancer. For PCT: ONE 100 mcg dose ONLY. Repeated or higher doses will cause prolonged HPTA suppression (chemical castration). Do not exceed one dose. Consult an endocrinologist.

Regulatory & Legal Status

FDA Status (US)
Approved

FDA-approved as Trelstar® for prostate cancer; used off-label for PCT and gender-affirming care

WADA Status (2026)
Prohibited (S4)

Competitive athletes subject to anti-doping controls should not use Triptorelin.

Classification

Prescription Drug

US Compounding: Not eligible / not available

⚠️ This information is for educational purposes only and may not reflect the most current regulatory updates. Always verify with official FDA, WADA, and jurisdiction-specific sources before use.

Interactions & Contraindications

Single low-dose PCT use and depot therapeutic use have opposite mechanisms (pulsatile vs continuous GnRH → stimulation vs suppression). Antiandrogens interact with the testosterone response post-triptorelin. Do not combine with other GnRH analogs.

Synergies & Common Stacks

Triptorelin provides the initial LH surge for HPG restart; Gonadorelin pulsatile dosing then maintains axis activity through recovery phase.

Dosing Quick Reference

Triptorelin— Dosing Guide
Dose Range
100 mcg (single dose PCT)
Half-Life
~3-5 hours
Frequency
Single dose (PCT)
Route
Subcutaneous
0.1 mg vial
💧 1 mL BAC water📐 0.1 mg/mL concentration💉 1 mcg/unit (100u syringe)
Healing & Recoverycalcmypeptide.com

Frequently Asked Questions

Why is a single dose of triptorelin used for PCT?
A single 100 mcg dose creates a massive LH/FSH surge that restarts the suppressed HPTA. Repeated or higher doses paradoxically shut down the axis via receptor desensitization — so ONE dose only is CRITICAL. This is a powerful tool that requires precision.
Is triptorelin safer than Clomid/Nolvadex for PCT?
Different mechanism: triptorelin provides a single sharp restart vs SERMs requiring weeks of daily dosing. Triptorelin is faster but the margin for error is razor-thin. Consult with an endocrinologist before use.

References

  1. Conn PM, Crowley WF Jr "GnRH agonist-induced testosterone surge in hypogonadal men".” NEJM (1991). PMID: 1975842

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