Reviewed & approved by Dr. Nova Reyes · Last checked 2026-10-25. ← Back to Evidence Library
Triptorelin: what the evidence says
At a glance
Triptorelin is a prescription drug. US labels are on DailyMed for advanced prostate cancer (Trelstar) and central precocious puberty in children (Triptodur). R5, R6 Gray-market vials are sold for "post-cycle therapy", which has never been tested.
What it is: a lab-made version of GnRH, the brain hormone that tells the pituitary to release LH and FSH. Long-acting forms first briefly raise and then shut down testosterone and estrogen production. R1, R2
What the evidence says: good trial evidence for shutting down testosterone in prostate cancer and for pausing early puberty. No trials found for the gray-market use as "PCT" (post-cycle therapy to restart a man's own testosterone after steroids). That use is anecdotal. R1, R2
Biggest risks: it is meant to lower sex hormones, so hot flashes, erectile problems and bone loss are expected. The US label also warns of an early testosterone surge ("flare"), allergic reactions including anaphylaxis, raised blood sugar and lipids, heart attack and stroke risk in men, seizures, severe skin reactions and QT prolongation. R1, R3, R5
Rating
| Human Human (prostate cancer: testosterone suppression) | Moderate: one active-comparator RCT cited on this page (284 men vs leuprolide) R1; FDA-approved prescription drug (Trelstar, NDA 020715 / 021288 / 022437) R5 |
| Human Human (central precocious puberty) | Limited: one open-label 6-month formulation study cited on this page (66 children) R2; FDA-approved prescription drug (Triptodur, NDA 208956) R6 |
| Human Human (gray-market "PCT" / testosterone restart) | No human data: no trials found |
| Animal Animal evidence | Not rated here |
| Regulatory | FDA-approved prescription drug: Trelstar (NDA 020715, 021288, 022437) and Triptodur (NDA 208956) R5, R6 · Not approved for PCT · WADA 2026: prohibited at all times in males (S2.2.1, named) R4 |
| Established human dose | For labeled uses only, see the product label. Trial arms are in Study details. No studied amount exists for PCT use |
Evidence verdict: Human (prostate cancer): Moderate · Human (precocious puberty): Limited · Human (gray-market PCT): No human data Card verdict: Moderate (prostate cancer testosterone suppression) · Early puberty: Limited · Post-cycle therapy: No human data Card note: Varies by use, see page
This page reports what studies used. It is not dosing advice.
Legend: HUMAN data · ANIMAL / LAB data · UNKNOWN · UNVERIFIED: not yet confirmed against a primary source
What is it?
Triptorelin is a GnRH agonist: a modified version of the natural hormone that controls the reproductive axis. Given continuously as a long-acting injection, it first causes a brief surge in LH and testosterone ("flare") and then switches the system off. R1 Doctors use it to lower testosterone in prostate cancer R1 and to pause early puberty in children. R2
Does it work?
- Human Prostate cancer: in 284 men, triptorelin kept testosterone at castrate level as well as leuprolide (96.2% vs 91.2% cumulative maintenance), though it got there slightly more slowly in the first month (91.2% vs 99.3% at day 29). R1
- Human Early puberty: in 66 Chinese children, all had suppressed LH at month 6 with a six-month formulation, and 98.5% still did at month 12. Funded by the maker (Ipsen). R2
- Unknown Gray-market "PCT": online forums describe a single small injection to "restart" testosterone after steroid use. We found no published trial of this. Its approved effect is the opposite: long-term use shuts testosterone down. R1 Anecdotal claims only.
Is it safe?
What the US labels warn about (labeled uses):
- Caution Trelstar (prostate cancer): anaphylaxis, allergic reactions and angioedema; a testosterone "flare" early in treatment that can worsen prostate cancer, including spinal cord compression and urinary blockage; metabolic changes (high blood sugar, diabetes, high lipids, fatty liver); higher risk of heart attack, sudden cardiac death and stroke in men; convulsions; severe skin reactions (SCARs); QT prolongation; possible fetal harm. Most common side effects: hot flushes, bone and muscle pain, erectile dysfunction, headache, leg swelling and testicular shrinkage. R5
- Caution Triptodur (children with precocious puberty): a temporary rise in puberty signs (including vaginal bleeding) early in treatment; psychiatric effects such as mood swings, irritability and aggression; convulsions; severe skin reactions; and pseudotumor cerebri (raised pressure in the skull: headache, vision changes). R6
What trials and reports add:
- Caution In the prostate cancer trial, both drugs were "well tolerated" per the authors. R1
- Caution Bone: a report of long-term triptorelin in men treated for paraphilia describes bone-loss side effects. R3
- Unknown Effects of one-off gray-market use in healthy men have not been studied.
Gray-market "research use only" Triptorelin: extra risks
Unknown contents. Products sold online as "research use only" or "not for human use" are not made under drug-quality rules, so identity, strength and sterility are unknown. This is a general caution; we have not found testing data for this product specifically. Unknown
Opposite effect risk. Repeated or long-acting use lowers testosterone rather than raising it. R1
What we don't know
- Unknown Whether any amount reliably restarts testosterone after steroid use
- Unknown Safety of gray-market products
- Unknown Long-term effects of one-off use in healthy men
Is it legal?
US FDA: Approved prescription drug — Trelstar (triptorelin pamoate for injectable suspension, NDA 020715, NDA 021288, NDA 022437) for palliative treatment of advanced prostate cancer and Triptodur (triptorelin extended-release injectable suspension, NDA 208956) for central precocious puberty (verified via openFDA / Drugs@FDA and DailyMed, Oct 24, 2026). R5, R6 EU brand (Decapeptyl): UNVERIFIED, not checked against EMA. Using it for PCT would be off-label and needs a prescription where it is approved. UK, Japan, China: UNVERIFIED not checked against MHRA, PMDA or NMPA. WADA: prohibited at all times (in and out of competition) in males under S2.2.1, "testosterone-stimulating peptides in males", which names triptorelin; S2 substances are non-Specified R4.
Study details
These are doses researchers used, not recommendations.
R1 Human Human: Triptorelin vs leuprolide in advanced prostate cancer (Heyns 2003)
| Study | People / model | Route | Dose used | Follow-up | Reported | Side effects / dropouts | Citation |
|---|---|---|---|---|---|---|---|
| Heyns 2003 | 140 triptorelin, 144 leuprolide | Intramuscular | Triptorelin 3.75 mg vs leuprolide 7.5 mg every 28 days, 9 injections | 253 days | Castrate testosterone at day 29: 91.2% vs 99.3%; equivalent at day 57 (97.7% vs 97.1%); cumulative maintenance 96.2% vs 91.2% | "Both treatments were well tolerated" | PMID 12887472 |
R2 Human Human: Six-month formulation in central precocious puberty (Yu 2024)
Ipsen-funded, open-label, single-arm. NCT05029622.
| Study | People / model | Route | Dose used | Follow-up | Reported | Side effects / dropouts | Citation |
|---|---|---|---|---|---|---|---|
| Yu 2024 | 66 children (93.9% girls) | Injection | Triptorelin pamoate 22.5 mg on day 1 and month 6 | 12 months | LH suppression 100% at month 6; 98.5% at month 12 | Not detailed in abstract excerpt | PMID 39412628 |
R3 Human Human: Bone side effects with long-term triptorelin for paraphilia
Title-level reference only; full text not reviewed. PMID 17971105
R5–R6 Labels
- R5 Trelstar label on DailyMed: indication, Warnings and Precautions 5.1–5.10, common adverse reactions. Read Oct 24, 2026.
- R6 Triptodur label on DailyMed: Warnings and Precautions 5.1–5.5. Read Oct 24, 2026.
Full reference list (PubMed entries verified Oct 24, 2026)
- R1 Heyns CF, et al. BJU Int. 2003;92(3):226-31. PMID 12887472
- R2 Yu X, et al. Adv Ther. 2024;41(12):4537-4556. PMID 39412628
- R3 Side effects of pharmacotherapy on bone with long-acting gonadorelin agonist triptorelin for paraphilia. J Sex Med. 2008. PMID 17971105
- R4 WADA. World Anti-Doping Code International Standard: Prohibited List 2026 (in force Jan 1, 2026). https://www.wada-ama.org/sites/default/files/2025-09/2026list_en_final_clean_september_2025.pdf (text read Oct 24, 2026)
- R5 Trelstar (triptorelin pamoate) prescribing information, Verity Pharmaceuticals, DailyMed (published Jul 10, 2026). https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=b1b84d62-a369-a4b7-5c41-dd1f553a18f3
- R6 Triptodur (triptorelin) prescribing information, Azurity Pharmaceuticals, DailyMed (published Sep 29, 2025). https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=f41380e7-b830-432d-a5f5-a872932f107e
Disclaimer
This page summarizes published research for education and harm reduction; it is not medical advice or a recommendation to use Triptorelin. Talk to a clinician you trust before using any drug, and report side effects to FDA MedWatch.
Approved for Adam Greene by Dr. Nova Reyes, 2026-10-25.