Important limitations
- Individual claims and source links have not yet completed editorial verification.
- Evidence level, applicable study model, formulation, route and population remain unassigned.
Triptorelin
Triptorelin is a synthetic decapeptide analog of gonadotropin-releasing hormone (GnRH), used in advanced prostate cancer therapy, hormone-related treatments, and fertility preservation.
Dosing & scaling, explained
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Evidence context
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Storage, handling and interpretation
Product identity
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Storage & handling
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Prepared solutions
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Reported protocols for Triptorelin
What published studies and recent community write-ups report about amounts, timing and course length. 9 clinical, 1 preclinical and 3 community-reported rows, each linked to its source. These are descriptions of what others report, not instructions, and nothing here is medical advice.
| Context | Dose | Frequency | Route | Course | Source |
|---|---|---|---|---|---|
| Clinical9 rows | |||||
| FDA label, Trelstar depot for advanced prostate cancerMen with advanced prostate cancer | 3.75 mg, 11.25 mg or 22.5 mg (triptorelin pamoate) | One injection every 4 weeks (3.75 mg), every 12 weeks (11.25 mg) or every 24 weeks (22.5 mg) | Intramuscular, into either buttock, alternating sides | Continuous; usually continued after the cancer becomes castration-resistantNone described | DailyMed, National Library of Medicine2026 |
| The 2026 label stresses that the three strengths release at different rates and cannot be added together to make another schedule. Testosterone rises above baseline after the first injection and then drops below 50 ng/dL within four weeks in most men, and the label warns about tumor flare, metabolic changes, QT prolongation and loss of bone density during long treatment. | |||||
| Pivotal depot trials summarized in the Trelstar label277 men (3.75 mg trial), 346 men (11.25 mg trial) and 120 men (22.5 mg trial) with advanced prostate cancer, mean age 71 | 3.75 mg every 28 days (up to 9 doses), 11.25 mg every 12 weeks (up to 3 doses) or 22.5 mg every 24 weeks (2 doses) | As above | Intramuscular | 253 days (3.75 mg and 11.25 mg) or 337 days (22.5 mg)None | DailyMed, National Library of Medicine2026 |
| Castrate testosterone (50 ng/dL or less) was reached by day 29 in 91.2%, 97.7% and 97.5% of men on the monthly, 3-month and 6-month products, and was maintained from day 57 to the end of the study in 96.2%, 94.4% and 93.3%. Hot flushes were the most common adverse event (58.6% on 3.75 mg and 73.0% on 11.25 mg), and the 22.5 mg study had no comparator arm. | |||||
| FDA label, Triptodur for central precocious pubertyChildren aged 2 years and older with central precocious puberty | 22.5 mg in 2 mL diluent | Once every 24 weeks | Intramuscular, given only by a healthcare provider | Until the physician judges that puberty should be allowed to startNone described | DailyMed, National Library of Medicine2025 |
| The label asks for LH or sex-steroid checks 1 to 2 months after the first dose and with each later dose, height measurements every 3 to 6 months and periodic bone-age films. A 2025 revision added a warning for severe skin reactions; pregnancy is a contraindication. | |||||
| Phase 3 trial of the 6-month formulation in children44 treatment-naive children (39 girls aged 2-8 and 5 boys aged 2-9) with central precocious puberty at 18 centers in the US, Chile and Mexico | 22.5 mg | Two injections 24 weeks apart | Intramuscular | 48 weeksNone | Journal of Pediatric Endocrinology and Metabolism (PubMed)2016 |
| Stimulated LH fell to prepubertal levels (5 IU/L or less) in 93.2% of children at month 6 and in 97.7% at month 12, with no unexpected drug-related adverse events. The study was open-label with no comparison group, which is typical for this indication but limits what it can say about safety. | |||||
| Decapeptyl 0.1 mg daily for IVF downregulation (Canadian product monograph)Women undergoing controlled ovarian stimulation for assisted reproduction | 0.1 mg (100 mcg triptorelin acetate, 95.6 mcg free base) in 1 mL | Once daily | Subcutaneous, lower abdominal wall, rotating sites; first injection under 30 minutes of medical observation | Usually 4-7 weeks; gonadotropins are added after 2-4 weeks and treatment stops when follicles are matureNot applicable; discontinuation considered if downregulation is not confirmed after 4 weeks | Ferring Inc. (Health Canada product monograph)2025 |
| The 2025 monograph describes starting on cycle day 2 or 3 or on day 21 to 23, and reports an elimination half-life of roughly 3 to 5 hours, so the drug is cleared well before embryo transfer. This daily low-dose form is a different product from the depot injections and is not approved in the United States. | |||||
| Single-dose ovulation trigger, randomized IVF trial510 women aged 35 and older undergoing IVF or ICSI on a non-downregulation protocol with low OHSS risk | 0.2 mg alone, or 0.2 mg plus 2,000 IU hCG (dual trigger), versus 6,000 IU hCG alone | Single injection on the trigger day | Subcutaneous | One stimulation cycleNot applicable | Human Reproduction (PubMed)2022 |
| The number of eggs retrieved did not differ between the three triggers, but the dual trigger produced more good-quality and viable embryos than either single trigger. Live birth after frozen transfer was higher with the dual trigger than with triptorelin alone (32.6% versus 14.1%) but not better than hCG alone. | |||||
| Ovarian protection during chemotherapy (PROMISE-GIM6)281 premenopausal women with stage I to III breast cancer at 16 Italian centers | 3.75 mg | Every 4 weeks, starting at least 1 week before chemotherapy | Intramuscular | For the duration of chemotherapyStopped when chemotherapy ended | JAMA (PubMed)2011 |
| Early menopause one year after chemotherapy occurred in 8.9% of women who received triptorelin versus 25.9% with chemotherapy alone. At a median of 12.4 years, disease-free and overall survival were no different between arms, including in hormone-receptor-positive disease, and 9 versus 4 women had a later pregnancy. | |||||
| Adjuvant ovarian suppression for 5 years (SOFT and TEXT)4,690 premenopausal women with hormone-receptor-positive early breast cancer | 3.75 mg (Decapeptyl Depot or Trelstar Depot) | Every 28 days | Intramuscular | 5 years, unless oophorectomy or ovarian irradiation replaced it after at least 6 monthsNone | New England Journal of Medicine2014 |
| Triptorelin was the main method of ovarian suppression alongside daily exemestane 25 mg or tamoxifen 20 mg. Exemestane plus ovarian suppression gave 91.1% disease-free survival at 5 years against 87.3% with tamoxifen plus suppression, with grade 3 or 4 adverse events in about 30% of both groups. | |||||
| Single 100 mcg dose after anabolic steroid use, case reportOne 34-year-old man with hypogonadotropic hypogonadism months after stopping internet-bought anabolic steroids | 100 mcg | Single injection (a standard triptorelin stimulation test) | Injection; the abstract does not specify the site | One dose, followed for one monthNot applicable | Fertility and Sterility (PubMed)2010 |
| Ten days after the test dose his testosterone was 7.0 ng/mL, up from 1.7 ng/mL (laboratory range 2.7-10) just before it, and within a month it was in the normal range with energy and libido reported back to normal. This is a single case published mainly as a warning about online steroid sales; it cannot show that the dose, rather than time, produced the recovery. | |||||
| Preclinical1 row | |||||
| Animal carcinogenicity and fertility studies reported in the labelRats and mice (carcinogenicity); female rats (fertility) | 120, 600 or 3,000 mcg/kg every 28 days (rats); up to 6,000 mcg/kg every 28 days (mice); 2, 20 or 200 mcg/kg per day (rat fertility) | Every 28 days for 13-19 months (rats) or 18 months (mice); daily for 60 days (fertility) | Injection (slow-release microspheres for the fertility arm) | Up to 19 monthsNot applicable | DailyMed, National Library of Medicine2026 |
| Rats given 0.3 to 8 times the human monthly dose had higher mortality and a dose-related rise in benign and malignant pituitary tumors, an effect not seen in mice at 8 times the human dose. The female rat doses, equal to 0.2 to 16 times the estimated human daily dose, did not affect fertility after a recovery period of at least four estrous cycles. | |||||
| Community-reported3 rows | |||||
| Community single-shot restart protocol | 100 mcg (10 units of a 2 mg vial reconstituted in 2 mL) | Once, never repeated | Subcutaneous | One injectionNo repeat; the guide warns that daily use would suppress testosterone within 10-14 days | Community resource2025 |
| This 2025 dosing page frames the 100 mcg shot as a last resort when SERMs or hCG have failed, and sets it against the 3.75 to 22.5 mg depot doses that are designed to shut the axis down. It states that even one clinical-sized dose can desensitize the pituitary and that recovery after depot therapy can take months. | |||||
| Vendor-affiliated research guide to the flare-based restart | 100 mcg | Single injection | Subcutaneous | One dose, with labs at about 3 monthsNone; repeated dosing described as the route to suppression | Community resource2026 |
| A March 2026 guide from a peptide retailer describes the LH and FSH flare lasting 1 to 3 days as the only part of the pharmacology the restart relies on, and lists the 3.75 mg monthly and 11.25 mg quarterly oncology schedules for contrast. It concedes that the restart rests on case reports with no randomized trial and that the best timing after steroid cessation is unknown. | |||||
| Bodybuilding overview of informal use | 100 mcg | Single injection, described as a last-resort option | Injection | One doseRe-dosing discouraged | Community resource2025 |
| A December 2025 bodybuilding article summarizes the informal practice as one 100 mcg injection when SERM or hCG regimens have failed, with LH, FSH and testosterone checked before and after. It lists suppression, estrogen imbalance and unreliable grey-market product as the main risks and notes that possession without a prescription is illegal in many countries. | |||||
How a course is commonly described
- Days 1-3: flareClinical
After the first injection of any formulation, LH, FSH, testosterone and estradiol rise above baseline for a few days. In prostate cancer this surge can worsen symptoms, which is why at-risk men are monitored; in the community restart protocol this surge is the whole point.
- Weeks 2-4: suppressionClinical
With a depot in place, pituitary GnRH receptors desensitize and testosterone falls to castrate levels (50 ng/dL or less) by day 29 in more than 91% of men. In the IVF protocol, downregulation is confirmed after 2 to 4 weeks before gonadotropins are started.
- Months 1-12: maintenanceClinical
Repeat depot injections every 4, 12 or 24 weeks hold suppression in 93% to 96% of men through 9 to 11 months, and triptorelin did not accumulate over 9 to 12 months of dosing. In children with precocious puberty, LH suppression held in at least 93% at every visit through month 12.
- Years 1-5: long-term adjuvant useClinical
In the SOFT and TEXT breast cancer trials, 3.75 mg every 28 days continued for five years alongside oral endocrine therapy, with oophorectomy allowed as a replacement after at least six months. This is the longest planned course in the triptorelin literature.
- Stopping and recoveryCommunity-reported
The label describes the hormonal effects as usually reversible after treatment ends, and community guides say recovery after depot therapy can take months. The single-dose restart is described as one injection with bloodwork afterwards and no second dose, because repeating it would move the user from the flare phase into suppression.
- Every schedule above except the community restart comes from prescription use under medical monitoring, and the depot products exist to suppress sex hormones, not to raise them. Dose and frequency decide which effect a person gets.
- The 100 mcg single-dose restart rests on one published case report and on the long-standing use of 100 mcg as a diagnostic stimulation test. No controlled trial has compared it with SERMs, hCG or simply waiting after anabolic steroid use.
- Triptorelin is prescription-only everywhere and is named under S2.2.1 of the 2026 WADA Prohibited List as a testosterone-stimulating peptide banned at all times in male athletes.
Sources for this section (12)
- TRELSTAR (triptorelin pamoate for injectable suspension): Prescribing Information
- TRIPTODUR (triptorelin) for extended-release injectable suspension: Prescribing Information
- Efficacy and safety of triptorelin 6-month formulation in patients with central precocious puberty
- DECAPEPTYL (triptorelin acetate injection 0.1 mg/mL): Product Monograph Including Patient Medication Information
- Ovulation triggering with hCG alone, GnRH agonist alone or in combination? A randomized controlled trial in advanced-age women undergoing IVF/ICSI cycles
- Effect of the gonadotropin-releasing hormone analogue triptorelin on the occurrence of chemotherapy-induced early menopause in premenopausal women with breast cancer: a randomized trial
- Long-Term Outcomes With Pharmacological Ovarian Suppression During Chemotherapy in Premenopausal Early Breast Cancer Patients
- Adjuvant Exemestane with Ovarian Suppression in Premenopausal Breast Cancer
- Anabolic steroids purchased on the Internet as a cause of prolonged hypogonadotropic hypogonadism
Plus 3 community resources (dosing guides, forum threads and vendor write-ups), reported above but not linked.
Overview
Triptorelin is a synthetic analog of gonadotropin-releasing hormone in which the glycine at position 6 is replaced by D-tryptophan, which makes it far more resistant to breakdown and more potent at the pituitary GnRH receptor than the natural hormone. A first dose causes a short surge of LH, FSH and sex steroids; with continuous exposure the receptor desensitizes and testosterone or estradiol fall to castrate levels within two to four weeks. In the United States it is approved as Trelstar (2000) for advanced prostate cancer and as Triptodur (2017) for central precocious puberty, and outside the United States Decapeptyl formulations are also licensed for endometriosis, fibroids, breast cancer and, as a 0.1 mg daily injection, for pituitary downregulation in IVF. It has been used in large breast cancer trials to suppress ovarian function, as a single 0.2 mg trigger for egg maturation, and in bodybuilding circles as a one-time 100 mcg injection meant to restart testosterone after anabolic steroid use; triptorelin is prescription-only and is named on the WADA Prohibited List for male athletes.
What researchers are exploring
These themes organize the educational information currently available. Individual claims remain under source review and are not treatment claims.
- 1
Research on Triptorelin
Triptorelin is used in cancer treatment, fertility preservation, and hormone-related conditions. It can stimulate testosterone and estrogen suppression, aid in breast cancer treatment, manage prostate cancer, and assist…
What is known and what still needs verification
Available context is organized without assigning unsupported study models or evidence grades.
- Not graded
Research on Triptorelin
Triptorelin is used in cancer treatment, fertility preservation, and hormone-related conditions. It can stimulate testosterone and estrogen suppression, aid in breast cancer treatment, manage prostate cancer, and assist in fertility preservatTriptorelin, an…
Chemistry identifiers
Sequence, synonyms and registry identifiers as recorded in PubChem, the National Library of Medicine's open chemistry database. Formula, mass and CAS number are summarized at the top of the page.
Sequence
pGlu-His-Trp-Ser-Tyr-D-Trp-Leu-Arg-Pro-Gly-NH2
Also listed as
Trelstar, Decapeptyl, Triptodur, Gonapeptyl, (D-Trp6)-GnRH, CL-118532, UNII 9081Y98W2V, CHEBI:63633
InChIKey
VXKHXGOKWPXYNA-PGBVPBMZSA-N
IUPAC name
(2S)-N-[(2S)-1-[[(2S)-1-[[(2S)-1-[[(2S)-1-[[(2R)-1-[[(2S)-1-[[(2S)-1-[(2S)-2-[(2-amino-2-oxoethyl)carbamoyl]pyrrolidin-1-yl]-5-(diaminomethylideneamino)-1-oxopentan-2-yl]amino]-4-methyl-1-oxopentan-2-yl]amino]-3-(1H-indol-3-yl)-1-oxopropan-2-yl]amino]-3-(4-hydroxyphenyl)-1-oxopropan-2-yl]amino]-3-hydroxy-1-oxopropan-2-yl]amino]-3-(1H-indol-3-yl)-1-oxopropan-2-yl]amino]-3-(1H-imidazol-5-yl)-1-oxopropan-2-yl]-5-oxopyrrolidine-2-carboxamide
Limitations and unknowns
Sources
1 link carried over from the earlier page, awaiting verification.