Is triptorelin FDA-approved, and what does the research show?

What is triptorelin?

Triptorelin is a prescription hormone drug for prostate cancer and for early puberty in children, not a wellness peptide ¹, ³. It is a man-made analog of gonadotropin-releasing hormone, GnRH ¹. GnRH is the hormone the base of the brain sends to the pituitary gland, which in turn drives the testes and ovaries.

The Trelstar label calls it "a synthetic decapeptide agonist analog of gonadotropin releasing hormone (GnRH)" ¹. A decapeptide is a chain of ten amino acids, and an agonist is a molecule that switches a receptor on, as the body's own hormone does. Its sixth amino acid is a mirror-image form of tryptophan ¹.

In the United States it is sold as a pamoate salt in two products, Trelstar and Triptodur ¹, ³. In both, the drug sits in biodegradable microgranules that release it slowly after an injection into a muscle ¹, ³.

Is triptorelin FDA-approved?

Yes. Triptorelin is approved by FDA as two prescription medicines, Trelstar and Triptodur, each for one use ¹, ³. Drugs@FDA, FDA's public record of approved drugs, lists Trelstar under new drug application (NDA) 020715, approved on June 15, 2000, with marketing status "Prescription" ². FDA classed it as a new molecular entity, a drug it had never approved before ². The two later Trelstar strengths hold their own applications, approved in 2001 and 2010, also "Prescription" ².

Triptodur holds NDA 208956, approved on June 29, 2017, with the same status ⁴. All four applications were listed as of November 6, 2026, the date of the dataset's last update ², ⁴.

The Trelstar label approves it "for the treatment of advanced prostate cancer" ¹. The label calls the treatment androgen deprivation therapy ¹. Androgens are the male hormones, and the label says the tissues that depend on them "become quiescent" once they are withdrawn ¹. The Triptodur label approves it "for the treatment of pediatric patients 2 years of age and older with central precocious puberty (CPP)" ³. Central precocious puberty is puberty that starts too early because the brain's GnRH signal switches on ahead of time; the label's trial enrolled children aged 2 to 9 ³.

Both products are prescription-only, and both labels place the injection in a professional's hands ¹, ³. Trelstar "must be administered under the supervision of a physician," and Triptodur "must only be administered by a healthcare provider" ¹, ³. Neither label lists a weight-loss, muscle-building, anti-aging or performance use ¹, ³. The Trelstar label adds that safety and efficacy "have not been established in females," and that safety and effectiveness "in pediatric patients have not been established" ¹. The Trelstar label was revised in June 2026 and the Triptodur label in September 2025 ¹, ³.

See the FDA status of every peptide, updated weekly.

How does triptorelin work?

Triptorelin acts in two phases, and the second phase is the treatment ¹. Like GnRH itself, it binds the pituitary's GnRH receptors and at first stimulates them ¹. The Trelstar label describes "a transient surge in circulating levels of luteinizing hormone (LH), follicle-stimulating hormone (FSH), testosterone, and estradiol" after the first injection ¹. LH and FSH carry the pituitary's orders to the testes and ovaries, which answer with testosterone and estradiol ³. In the Trelstar trials, mean testosterone rose above baseline "during the first week following the initial injection" and was back at baseline or below "by the end of the second week of treatment" ¹.

The label calls this first rise the tumor flare, and in men with prostate cancer it can briefly worsen the disease ¹. In children it can bring a brief increase in the signs of puberty, including vaginal bleeding, in the first weeks or after a later dose ³.

Continued without a break, the stimulation has the reverse effect: the pituitary's receptors are desensitized and the gland stops answering ¹. The label says that "usually 2 to 4 weeks after initiation of therapy, a sustained decrease in LH and FSH secretion and marked reduction of testicular steroidogenesis are observed" ¹. Steroidogenesis is the making of steroid hormones, testosterone among them. Testosterone falls to "a level typically seen in surgically castrated men," which the label sets at under 50 ng/dL, nanograms per deciliter of blood, and calls the castrate level ¹. The effects "are usually reversible after cessation of therapy" ¹.

In children with early puberty, Triptodur's label reports the suppression bringing stimulated LH, estradiol and testosterone down to prepubertal levels, with FSH suppressed ³. It puts the fall at four weeks and expects pituitary and gonadal function to return within six to twelve months of stopping ³. Leuprolide and goserelin, two other GnRH agonists WADA lists beside triptorelin, are different molecules with their own pages ⁶. A randomized trial compared triptorelin with leuprolide in men with advanced prostate cancer ⁵.

What does the research show?

The outcome in the prostate trials was not survival or tumor size but testosterone ¹. The label's primary endpoints were "achievement of castration by Day 29 and maintenance of castration from Day 57 through Day 253" ¹.

Studied in people, head to head with leuprolide: a randomized, multicenter trial published in August 2003 compared the two in men with advanced prostate cancer ⁵. The paper reports 284 men treated, 140 on triptorelin and 144 on leuprolide, each injected monthly for nine months ⁵.

At day 29, 91.2 percent of the triptorelin arm had castrate testosterone against 99.3 percent of the leuprolide arm ⁵. That is a difference of 8.0 points in leuprolide's favor ⁵. The 95 percent confidence interval, the range the true difference most likely falls in, ran from 16.9 to 1.4 points ⁵. By day 57 the two arms were equivalent, 97.7 against 97.1 percent ⁵.

Between days 29 and 253 the mean castration maintenance rates were 98.8 percent on triptorelin and 97.3 on leuprolide ⁵. The cumulative rates were 96.2 against 91.2, and the authors report both pairs as equivalent ⁵.

Nine-month survival was 97.0 percent on triptorelin and 90.5 on leuprolide ⁵. The authors report that difference as statistically significant, with a P value of 0.033 ⁵. A gap this large would arise by chance about 3 times in 100 if the drugs were equal ⁵. Survival was one of the trial's secondary endpoints, the outcomes measured beside the main one, which was testosterone ⁵.

The authors concluded that triptorelin "reduced testosterone concentrations less rapidly, but maintained castration as effectively as leuprolide," and "there was no evidence that the slower onset of castration caused deleterious effects" ⁵. LH levels, bone pain, prostate-specific antigen, the blood marker used to follow prostate cancer, and quality of life were equivalent between the arms ⁵.

The Trelstar label describes a randomized, active-control trial of 277 men aged 47 to 89, comparing its monthly strength (140 men treated) with "an approved GnRH agonist" ¹. Active-control means the comparison was another working drug, not a placebo. FDA's 2000 statistical review describes one trial against Lupron, 285 men enrolled and 277 analyzed, with the paper's day-29 and day-57 rates ⁷, ⁵. Castrate testosterone was reached by day 29 in 125 of 137 evaluable men (91.2 percent) and held from day 57 to day 253 in 96.2 percent ¹.

A second randomized trial of 346 men compared a longer-acting Trelstar strength with the monthly one ¹. On the longer-acting strength, 167 of 171 men counted (97.7 percent) were castrate by day 29, and 94.4 percent stayed so to day 253 ¹. A single-arm trial of 120 men tested the longest-acting strength: 117 (97.5 percent) were castrate by day 29 and 93.3 percent through day 337 ¹. The mean age in all three trials was 71 ¹.

Studied in children: Triptodur's approval rests on one open-label, single-arm study of 44 children aged 2 to 9 with central precocious puberty ³. Open-label means everyone knew what was given, and single-arm that every child received the drug. They were 39 girls and 5 boys, followed for 12 months over two injections ³. At every time point at least 93 percent had LH suppressed to prepubertal levels after a stimulation test; the primary endpoint, at month 6, was 41 of 44 ³. At month 12 the figure was 43 of 44 ³.

At least 79 percent of the girls had prepubertal estradiol and at least 80 percent of the boys prepubertal testosterone at each check ³. At month 12, 95 percent showed no increase in the ratio of bone age to chronological age, and 89 percent had stabilized sexual maturation ³. The label calls the study "uncontrolled," so it measures suppression, not a result against another treatment or none ³.

Neither label nor the trial studied triptorelin for weight, body composition, muscle or performance in anyone ⁵, ¹, ³. The Trelstar label's only healthy volunteers were men in pharmacokinetic studies, which track a drug's levels in the body ¹. In them testosterone peaked on day 4 and fell to low levels by week 4 ¹.

What are the side effects?

The side effects follow the hormone changes. The Trelstar label says most of its adverse reactions "are a result of its pharmacological action," the rise in testosterone at the start and its fall once castration is reached ¹. Hot flashes, the label's "hot flush," led in every trial ¹. Judged related to treatment, they affected 58.6 percent of 140 men on the monthly strength and 73.0 percent of 174 in the second trial ¹. On the longest-acting strength, 72.5 percent of 120 reported them ¹.

Judged related to treatment, skeletal pain affected 12.1 and 13.2 percent in the first two trials, impotence 7.1 and 2.3 percent, and headache 5.0 and 6.9 percent ¹. In the 120-man trial, erectile dysfunction (10.0 percent) and testicular atrophy (7.5 percent) were counted as treatment-related in every case ¹. Diabetes or high blood sugar was reported in 5.0 percent of that trial, not ascribed to the drug ¹. The label also notes falls in hemoglobin and rises in glucose and liver enzymes on the two longer-acting strengths ¹.

The label's warnings cover the flare and more. Under "Tumor Flare" it says the early testosterone rise "may worsen prostate cancer and result in spinal cord compression and urinary tract obstruction," and that "spinal cord compression with weakness or paralysis of the lower extremities have occurred" ¹. Under "Metabolic Syndrome" it says GnRH agonists "may lead to metabolic changes such as hyperglycemia, diabetes mellitus, and hyperlipidemia," with non-alcoholic fatty liver disease, "including cirrhosis," seen after marketing ¹. Under "Cardiovascular Diseases" it reports an "increased risk of developing myocardial infarction, sudden cardiac death and stroke" with GnRH agonists in men, adding that "the risk appears low based on the reported odds ratios" ¹.

It also warns of convulsions, with or without a history of seizures ¹. It warns of severe skin reactions, including Stevens-Johnson syndrome and toxic epidermal necrolysis, in which the skin blisters and peels ¹. Androgen deprivation with Trelstar "may prolong the QT/QTc interval," a measure of the heart's electrical recovery between beats ¹. Post-marketing reports add pituitary apoplexy, which the label describes as "a clinical syndrome secondary to infarction of the pituitary gland," mostly "within 2 weeks of the first dose, and some within the first hour" ¹. They also add depression with "suicidal ideation and attempt," blood clots, and interstitial lung disease ¹.

The label contraindicates Trelstar in anyone with "known hypersensitivity to triptorelin or any other component of the product, or other GnRH agonists or GnRH" ¹. Anaphylactic shock and angioedema have been reported ¹. It "can cause fetal harm when administered to a pregnant woman" and "may impair fertility in males of reproductive potential" ¹.

In children, Triptodur's trial of 44 recorded injection-site pain in 45 percent, and headache and nasopharyngitis, the common cold, in 13.6 percent each ³. Vaginal bleeding or a returned menstrual cycle occurred in 3 of 39 girls ³. Its warnings cover the initial rise in puberty signs, psychiatric events including "crying, irritability, impatience, anger, and aggression," convulsions, and the same severe skin reactions ³. They also cover pseudotumor cerebri, a rise in pressure inside the skull with headache and blurred vision, reported in children on GnRH agonists ³. Pregnancy is a contraindication on the Triptodur label ³.

In sport

Triptorelin is prohibited at all times under the World Anti-Doping Agency's (WADA's) 2026 Prohibited List ⁶. WADA names it in section S2.2.1, "Testosterone-stimulating peptides in males," whose bullet reads in full: "gonadotrophin-releasing hormone (GnRH, gonadorelin) and its agonist analogues (e.g. buserelin, deslorelin, goserelin, histrelin, leuprorelin, nafarelin and triptorelin)" ⁶. Section S2, "Peptide hormones, growth factors, related substances, and mimetics," is prohibited in and out of competition ⁶. All of its substances are non-specified, which under WADA's Code sets them apart from the specified substances "more likely to have been consumed or used by an Athlete for a purpose other than the enhancement of sport performance" ⁶.

What JumpstartMD offers

JumpstartMD does not prescribe triptorelin. Our peptide library covers it so you have the facts on its FDA status and the evidence, current as of November 10, 2026.

Ready to talk?

Book FREE Consultation

Share your details and a JumpstartMD team member will reach out shortly. Or call 408.478.3496 for your free, no-obligation consultation.

Share your details and a JumpstartMD team member will reach out when we open.

Disclaimer

Compounded medications are not FDA-approved, and FDA does not review their safety, effectiveness, or quality before they are marketed. A licensed clinician decides after an evaluation whether a peptide is appropriate for you, and not every patient will qualify.