Triptorelin vs leuprolide
Last updated: October 5, 2026 · 6 min read · By the Grey Peptides Editorial Board
- Both are approved GnRH agonists that, given continuously, shut down testosterone and oestrogen production.
- In the main head-to-head prostate cancer trial, triptorelin was slower to reach castrate testosterone at one month but equally effective from two months on.
- In children with early puberty, the comparisons available are retrospective and found the two similarly effective.
- The practical differences are formulations and dosing intervals, not effectiveness.
Side by side
Triptorelin High and leuprolide High are both modified versions of GnRH, the ten-amino-acid hormone that tells the pituitary to release LH and FSH 1. The table is read from our encyclopedia entries.
| Field | Triptorelin | Leuprolide |
|---|---|---|
| Encyclopedia entry | Triptorelin Full entry | Leuprolide Full entry |
| Molecule class | Peptide | Peptide |
| Category | Sexual Health | Sexual Health |
| FDA status | FDA Approved | FDA Approved |
| Approved elsewhere | None recorded | None recorded |
| Evidence grade | High | High |
| Half-life | Not reported in the sources read | ≈ 3 hours |
| Formula | C64H82N18O13 | C59H84N16O12 |
| Molecular weight | 1,311.5 g/mol | 1,209.4 g/mol |
| WADA 2026 | Prohibited in males, at all times (S2.2.1) | Prohibited in males, at all times (S2.2.1) |
| WADA 2027 | Prohibited in males, at all times (S2.2.1) | Prohibited in males, at all times (S2.2.1) |
| In one line | A widely used long-acting GnRH agonist — FDA-approved as Trelstar for advanced prostate cancer and as Triptodur for pediatric central precocious puberty; approved internationally (Decapeptyl, Gonapeptyl) for endometriosis, uterine fibroids, and female infertility protocols. | The prototypical long-acting GnRH agonist: after a brief flare it shuts down testosterone and oestrogen, FDA-approved since 1985 in forms from a daily pen to six-month depots for prostate cancer, endometriosis, fibroids and central precocious puberty. |
| Mechanism | Binds GnRHR on pituitary gonadotrophs; continuous exposure causes receptor desensitization and downregulation after an initial testosterone/estradiol flare. Results in medically reversible chemical castration. | Binds the pituitary GnRH receptor as an agonist. At the start gonadotropins and sex steroids rise (testosterone about 50% above baseline per the label); continuous exposure then suppresses ovarian and testicular steroid production, reversibly on stopping. With depot dosing testosterone reached castrate levels by about three weeks (median 22 days on the 30 mg four-month depot). |
| Sources in the entry | 10 | 21 |
| Study cards | 7 | 17 |
| Dosage page | None | None |
How GnRH agonists work
Natural GnRH is released in pulses. A long-acting agonist does the opposite of what its name suggests in the long run: after a brief surge, the constant signal makes the pituitary stop responding, so LH and FSH fall and the testes or ovaries stop making testosterone or oestrogen. That shutdown is the treatment, whether the aim is to starve a hormone-driven prostate cancer, pause early puberty or shrink endometriosis. Both drugs do this; they differ in their exact sequence and, more importantly, in their delivery forms.
Head to head in prostate cancer
The main randomised comparison, published in 2003, gave 284 men with advanced prostate cancer monthly intramuscular injections of triptorelin 3.75 mg (140 men) or leuprolide 7.5 mg (144) for nine months. At day 29, fewer men on triptorelin had reached castrate testosterone levels (91.2% against 99.3%), but by day 57 the two were equivalent (97.7% against 97.1%), and the rates of maintaining castration from day 29 to day 253 were equivalent. Nine-month survival was higher with triptorelin (97.0% against 90.5%), a secondary finding the trial was not designed to test, and both drugs were well tolerated (randomised trial) 2.
The fair reading is equivalence on the main goal, with a slower start for triptorelin. The survival difference in a nine-month secondary analysis is not evidence that one drug prolongs life, and longer trials have not been built around that question.
What long-acting forms achieve
Much of what separates the drugs is formulation. For leuprolide, a 30 mg four-month depot brought testosterone to castrate levels in 96% of 49 men within four weeks, with a median of 22 days (uncontrolled trial) 3. Eligard, an in-situ gel injected under the skin, brought 98% of men on its one-month form and 94% on its three-month form to target testosterone in trials (review) 4. Triptorelin's depots reach up to six months.
A newer comparison point is oral: in the HERO trial of 934 men, oral relugolix, a GnRH antagonist pill, kept testosterone suppressed in 97% against 89% on leuprolide injections (randomised trial) 5. That puts both agonists in a field that now includes an oral alternative.
In children with early puberty
GnRH agonists are the standard treatment for central precocious puberty, when puberty starts years early because the brain's signal switches on too soon. A 2023 retrospective study of 110 girls compared leuprolide (48) with triptorelin (62): both were effective, about 42% reported mild menopause-like side effects, at similar rates in each group, with headache more often reported on triptorelin and nausea on leuprolide (cohort study) 6. A 2025 study of 69 overweight or obese girls found both suppressed LH well, with similar predicted adult height at the end of treatment (cohort study) 7.
For triptorelin's six-month form, a phase 3 single-arm trial in Chinese children showed treatment effects maintained at 12 months (uncontrolled trial) 8, and a three-month triptorelin pamoate trial reported efficacy and safety similar to published data for other agonists (uncontrolled trial) 9. No large randomised head-to-head trial in children was found.
US formulations, as of October 2026
Leuprolide has the larger US range: Lupron Depot for prostate cancer and, at lower doses, endometriosis and fibroids before surgery; Lupron Depot-Ped, Fensolvi and, since August 2026, Vobrig, a daily pen, for central precocious puberty; and Eligard and Camcevi for prostate cancer. Triptorelin is marketed in the US as Trelstar for advanced prostate cancer and Triptodur, approved in 2017, for central precocious puberty (dataset) 1.
A 2024 survey of 223 US paediatric endocrinologists found most were very familiar with monthly and three-monthly leuprolide and the histrelin implant, but fewer with six-monthly triptorelin (65%) or six-monthly leuprolide (45%), and a quarter were unaware of cost differences between paediatric and adult preparations (survey) 10. Familiarity and cost, rather than proven differences in effect, often decide which a family is offered.
Side effects in common
Because both work by lowering sex hormones, their side effects come from the same mechanism and largely overlap, including the brief hormone 'flare' before suppression sets in that every GnRH agonist produces. Where the two were compared directly in children, mild menopause-like symptoms were reported at similar rates with each, with headache somewhat more common on triptorelin and nausea on leuprolide (cohort study) 6. In the prostate cancer trial, both were well tolerated (randomised trial) 2. Each drug's label lists its side effects in full, and our entries summarise them.
How they compare (as of October 5, 2026)
Triptorelin and leuprolide are approved GnRH agonists that do the same job. In the 284-man head-to-head prostate cancer trial, triptorelin reached castrate testosterone more slowly at one month but was equivalent from two months on; in children with early puberty, retrospective comparisons found them similarly effective. The meaningful differences are which formulations are available, how often they are given and what they cost, which is why the choice usually comes down to the clinic's experience and the patient's circumstances.
Frequently asked questions
Is triptorelin better than leuprolide?
In the main prostate cancer trial they were equivalent at maintaining castrate testosterone; triptorelin was slower at day 29 (91.2% vs 99.3%) but equal by day 57.
Which is used for precocious puberty?
Both. Leuprolide (Lupron Depot-Ped, Fensolvi, Vobrig) and triptorelin (Triptodur) are approved in the US for central precocious puberty.
Do triptorelin and leuprolide have the same side effects?
Largely, because both work by lowering sex hormones; in a 110-girl comparison, mild menopause-like symptoms occurred at similar rates with each.
Is there an oral alternative?
For prostate cancer, oral relugolix, a GnRH antagonist, kept testosterone suppressed in 97% vs 89% on leuprolide in the HERO trial.
Related on Grey Peptides
Sources
- Grey Peptides dataset rows for triptorelin (Trelstar, NDA 021288, June 29, 2001, advanced prostate cancer; Triptodur, NDA 208956, June 29, 2017) and leuprolide (Lupron Depot 1989 for prostate cancer and, at 3.75 and 11.25 mg, endometriosis and fibroids; Lupron Depot-Ped 1993, Fensolvi 2020 and Vobrig 2026 for central precocious puberty; Eligard 2002, Camcevi 2021); read September 28 to October 1, 2026.
- Heyns, C. F., et al. (2003). Comparative efficacy of triptorelin pamoate and leuprolide acetate in men with advanced prostate cancer. BJU Int, 92(3), 226-31. PMID: 12887472
- Sharifi, R., et al. (1998). Leuprolide acetate (30-mg depot every four months) in the treatment of advanced prostate cancer. Urology, 51(2), 271-6. PMID: 9495710
- Sartor, O. (2003). Eligard: leuprolide acetate in a novel sustained-release delivery system. Urology, 61(2 Suppl 1), 25-31. PMID: 12667884
- Tutrone, R., et al. (2024). Testosterone Recovery for Relugolix Versus Leuprolide in Men with Advanced Prostate Cancer: Results from the Phase 3 HERO Study. Eur Urol Oncol, 7(4), 906-913. PMID: 38143206
- Valenzise, M., et al. (2023). Leuprolide and triptorelin treatment in children with idiopathic central precocious puberty: an efficacy/tolerability comparison study. Front Pediatr, 11, 1170025. PMID: 37266535
- Thaneetrakool, T., et al. (2025). Treatment of overweight and obese girls experiencing central precocious puberty: a comparison of the effectiveness of leuprolide acetate and triptorelin pamoate. Ann Pediatr Endocrinol Metab, 30(4), 207-212. PMID: 40916129
- Yu, X., et al. (2024). A Phase 3, Open-Label, Single-Arm Trial of the Efficacy and Safety of Triptorelin 6-Month Formulation in Chinese Children with Central Precocious Puberty. Adv Ther, 41(12), 4537-4556. PMID: 39412628
- Zenaty, D., et al. (2016). A 6-Month Trial of the Efficacy and Safety of Triptorelin Pamoate (11.25 mg) Every 3 Months in Children with Precocious Puberty: A Retrospective Comparison with Triptorelin Acetate. Horm Res Paediatr, 86(3), 188-195. PMID: 27603324
- Breidbart, E., et al. (2025). Precocious Puberty and GnRH Analogs: Current Treatment Practices and Perspectives among US Pediatric Endocrinologists. Horm Res Paediatr, 98(5), 491-502. PMID: 38718766
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