Triptorelin

Also known as: Triptorelin Acetate; Triptorelin Pamoate; Triptorelin Embonate

Overview

Triptorelin is a GnRH analog that first increases, then suppresses LH and FSH to lower testosterone and estrogen levels. Used for hormone-sensitive cancers, endometriosis, and gender-affirming therapy.

Benefits

- Suppresses sex hormone production

- Reversible control of gonadal function

- Reduces tumor progression

- Treats early puberty

Consider This Peptide If You Want To

- Suppress hormones for cancer, reproductive, or gender-affirming treatment

Dosage & Administration

Dosage Guidelines

Recommended Dosage

• Amount:3.75 mg

• Frequency:every4weeks

• Duration:3 months

• Rest Period:

• Time of Day:morning

• Ingestion:intramuscular

Must be administered by a healthcare professional. Initial dose may cause hormone flare before suppression begins. Calcium and vitamin D supplementation recommended for extended use to prevent bone density loss.

Administration Routes:Intramuscular Injection

Research Findings on Dosage:

Intramuscular Injection: ● Commonly Reported Dosage: 3.75 mg every 4 weeks, or long-acting formulations of 11.25 mg every 12 weeks or 22.5 mg every 24 weeks ● Duration: Varies by treatment goal (e.g., 3–6 months for precocious puberty; indefinite use in advanced prostate cancer) Administration Notes: ● Injected deeply into the gluteal muscle under medical supervision ● The first dose may trigger a transient hormone flare; symptoms such as increased pain or swelling can occur before suppression begins ● Patients commonly report hot flashes, mood swings, and libido changes during the suppression phase ● Calcium and vitamin D supplementation is frequently recommended to offset bone density loss during extended use

Mechanism of Action

How this peptide works in the body

Initial Activation of the HPG Axis: Triptorelin mimics endogenous GnRH and binds to GnRH receptors on gonadotropes in the anterior pituitary. This activates the phospholipase C (PLC) pathway, leading to the generation of inositol triphosphate (IP3) and diacylglycerol (DAG). The resulting calcium influx promotes exocytosis of LH and FSH, causing a transient spike in testosterone or estrogen levels. Desensitization and Downregulation of GnRH Receptors: With continuous stimulation, GnRH receptors become internalized and degraded. This downregulation halts the pulsatile release of LH and FSH, disrupting the feedback loop between the hypothalamus, pituitary, and gonads. Reduced LH levels diminish Leydig cell stimulation in testes (lowering testosterone), while reduced FSH impairs Sertoli cell activity and gametogenesis. In ovaries, estrogen and progesterone synthesis also fall sharply. Suppression of Gonadal Steroidogenesis: In men, the suppression of LH halts testicular testosterone production, reducing stimulation of androgen-responsive tissues. In women, suppressed LH and FSH inhibit follicular maturation and estrogen production, leading to an anovulatory, hypoestrogenic state. This effectively "shuts down" the reproductive endocrine system. Downstream Physiological Effects: The resulting hormone deprivation has multiple clinical effects: ● In prostate cancer, the absence of androgens slows tumor growth and reduces PSA levels. ● In endometriosis and fibroids, hypoestrogenism leads to regression of ectopic endometrial tissue and fibroid shrinkage. ● In central precocious puberty, the delay of sexual maturation normalizes growth and bone age trajectory. ● In transgender healthcare, Triptorelin is used to block unwanted secondary sex characteristics before or alongside cross-sex hormone therapy.

Consider Stacking With

- Calcium + Vitamin D

- Bisphosphonates/SERMs

- NSAIDs

Side Effects & Cautions

Common Side Effects

- Hot flashes, mood swings, headache, fatigue, injection pain

Cautions

- Avoid in pregnancy

- Long-term use may require add-back therapy

Rare Side Effects

- Bone density loss, cardiovascular strain, allergic reactions

Research & References

Research Highlights

● Triptorelin reduced serum testosterone to castration levels in over 95% of prostate cancer patients within 4 weeks of treatment ● In girls with central precocious puberty, it normalized growth velocity and pubertal development after 3–6 months ● In endometriosis patients, Triptorelin significantly reduced pelvic pain and lesion size compared to placebo and other GnRH analogs

References

Neely EK, Hintz RL. "Management of central precocious puberty with long-acting GnRH analogs." Endocrinol Metab Clin North Am. 2005;34(3):655–669. PMID: 16160045

Santen RJ, Allred DC. "Prostate cancer: the role of estrogen and estrogen receptors." J Steroid Biochem Mol Biol.2007;106(1–5):190–195. PMID: 17825290

Donnez J, Nisolle M. "Triptorelin depot formulations in the treatment of endometriosis." Gynecol Obstet Invest.2000;50(Suppl 1):36–39. PMID: 11093063

Gillessen S, Attard G. "Management of patients with advanced prostate cancer." Eur Urol Suppl.2015;14(6):459–468. PMID: 25840038