PT-141 is bremelanotide, the drug sold today as Vyleesi for women with low sexual desire. It began as something else: an erection drug for men. Its developer, Palatin Technologies, ran the early male studies, reported positive erectile responses, and then stopped. The approved product that eventually came out of the programme excludes men by name.
This page reports what the male record contains — the trials, their sizes and doses — and why it ends where it does. The women's trials are on our PT-141 for women page, harms across both sexes on our PT-141 side effects page, and the approved dose on our PT-141 dosage page. Peptide Lexicon explains what the molecule is in its PT-141 entry. Nothing here is a recommendation.
What the approved label says about men
The Vyleesi label (Cosette Pharmaceuticals, effective 13 November 2025, read via openFDA on 26 October 2026) approves bremelanotide for premenopausal women with acquired, generalised hypoactive sexual desire disorder. Under limitations of use it states: "VYLEESI is not indicated for the treatment of HSDD in postmenopausal women or in men. VYLEESI is not indicated to enhance sexual performance."
That sentence does two things. It excludes men, and it excludes the use most men buying PT-141 online have in mind.
The male trials, in order
Every published bremelanotide study in men that we found, from a PubMed search of 32 records combining bremelanotide or PT-141 with erectile, men or male (26 October 2026). Most of the 32 are reviews; these are the primary studies:
| Study | Who | Route and dose | What was measured | Result |
|---|---|---|---|---|
| Diamond 2004, Int J Impot Res | Healthy men; Viagra-responsive men with mild-to-moderate ED | Intranasal, ascending doses | Erections by RigiScan; pharmacokinetics | Significant erectile response above 7 mg; onset ~30 min; half-life 1.85–2.09 h |
| Rosen 2004, Int J Impot Res | Healthy men; men with inadequate response to Viagra 100 mg | Subcutaneous 0.3–10 mg (healthy); 4 or 6 mg (ED) | Erections by RigiScan | Significant above 1.0 mg in healthy men; significant at 4 and 6 mg in ED patients |
| Diamond 2005, Urology | 19 men with ED who responded to Viagra or Levitra | 7.5 mg intranasal + 25 mg sildenafil, crossover | Erections by RigiScan | Combination greater than sildenafil alone |
| Safarinejad 2008, J Urol | 342 married men aged 28–59 who did not respond to sildenafil | 10 mg intranasal, at least 16 home attempts | IIEF questionnaire, intercourse satisfaction | Positive in 33.5% vs 8.5% on placebo; more drug-related adverse effects (P = 0.01) |
| Clayton 2017, Clin Ther | 12 men and 12 women | 20 mg intranasal with alcohol | Safety and tolerability | Interaction study, not efficacy |
The first three were run by Palatin's own scientists; all three used RigiScan, a device that records penile rigidity in a laboratory, usually while participants watch sexual video. They show that the drug acts in men. They do not show what happens at home over months, which is what an approval needs.
The fourth is the only large efficacy trial — and in January 2023 The Journal of Urology attached an expression of concern to it. The PubMed record links the notice; it does not explain it, and we report only that it exists. A reader citing "a 342-man trial showed PT-141 works for ED" is citing a paper its own journal has flagged.
Why Palatin stopped
Palatin's annual report for the year to 30 June 2008, filed with the US Securities and Exchange Commission on 29 September 2008 (SEC EDGAR), gives the company's own account, in two places:
- "Bremelanotide has been studied extensively by us for sexual dysfunction in nasal formulations and in subcutaneously and intravenously injected formulations. In these trials, almost 2,000 patients received at least one dose of bremelanotide, with about 1,500 receiving multiple doses. Increases in blood pressure were observed in some patients, and this observed increase was a significant factor leading us to discontinue work on bremelanotide as a first-line therapy for sexual dysfunction."
- "We discontinued development of bremelanotide for sexual dysfunction after the FDA raised concerns about the acceptable benefit/risk ratio of bremelanotide as a first-line therapy for erectile dysfunction, primarily because of increases in blood pressure observed in some patients."
That is the developer, writing to investors, about its own drug. It is the most direct answer available to "why is there no PT-141 for men": the regulator questioned whether the erections were worth the blood-pressure rise in a population that already had Viagra-type drugs.
Palatin later returned to bremelanotide for women — a lower 1.75 mg dose, given by autoinjector a few times a month — and that programme became Vyleesi in 2019. The blood-pressure signal survived into the women's label: transient rises after each dose, and a contraindication in uncontrolled hypertension or known cardiovascular disease. The figures are on our side effects page.
What the men's doses were
The doses in the male studies were mostly intranasal 7.5 to 20 mg, or subcutaneous 1 to 10 mg in early dose-finding — not comparable with the women's 1.75 mg injection, because nasal absorption differs from injection. We report them as the history of a discontinued programme. Medibact Guides works through the arithmetic of the nasal form on its PT-141 nasal dosage page.
What has happened since
- No new trial in men. ClinicalTrials.gov lists 10 bremelanotide studies, none registered under erectile dysfunction and none recruiting men specifically; the conditions are HSDD, female arousal disorder, nausea, kidney disease, obesity and lactation (registry API, read 26 October 2026).
- A reopened question, not an answer. A 2026 commentary in the Journal of Clinical Psychopharmacology (Pfaus and Balon) asks in its title whether bremelanotide "should be considered for the treatment of sexual arousal and desire disorders in men". It is an opinion piece, not data.
- The adverse-event database. An openFDA query on 26 October 2026 counted 50 reports in men and 883 in women where sex was recorded. Fifty reports in men, for a drug not approved for them, show off-label use exists; they cannot give a side-effect rate.
Research PT-141 is not Vyleesi
The trials above used pharmaceutical bremelanotide of known strength. Most PT-141 sold to men online is a lyophilised powder labelled for research, of unverified content, used at doses and frequencies no trial tested. What the label says about women, and what Palatin's trials showed in men, describe a different product used in a different way. Men looking at the hormone side of sexual function will find kisspeptin's small men's trials on our kisspeptin for men page, and the testosterone options mapped on our peptides and testosterone page.
What is not established
- Efficacy in men at home over months — the large trial that measured it carries an expression of concern.
- A blood-pressure safety profile for men at any dose.
- Effects on desire, as distinct from erection, in men — the women's approval is for desire; the men's studies measured erection.
- Safety alongside PDE5 drugs beyond one 19-man laboratory study.
- Anything about research-labelled products.
Erectile problems can be an early sign of cardiovascular disease, which is exactly the population the blood-pressure concern bears on. Any treatment decision belongs with a clinician.
Sources and dates
- Vyleesi (bremelanotide injection) label, Cosette Pharmaceuticals, set f1d0c1b5-2f39-4bad-a6a4-0066e3ad5dcf, effective 13 November 2025 — indications and limitations read via openFDA 26 October 2026.
- Palatin Technologies Inc., Form 10-K for the fiscal year ended 30 June 2008, filed 29 September 2008, SEC accession 0001088020-08-000050 — read on SEC EDGAR 26 October 2026.
- Diamond LE et al. Int J Impot Res. 2004;16(1):51–9. PMID 14963471. Rosen RC et al. Int J Impot Res. 2004;16(2):135–42. PMID 14999221. Diamond LE et al. Urology. 2005;65(4):755–9. PMID 15833522. Safarinejad MR, Hosseini SY. J Urol. 2008;179(3):1066–71. PMID 18206919 (expression of concern, J Urol, 10 January 2023). Clayton AH et al. Clin Ther. 2017;39(3):514–26. PMID 28189361. Pfaus JG, Balon R. J Clin Psychopharmacol. 2026;46(3):245–8. PMID 41960633 — abstracts and records read 26 October 2026.
- ClinicalTrials.gov API v2, intervention "bremelanotide": 10 studies — 26 October 2026. openFDA drug adverse events, bremelanotide, count by sex: 883 female, 50 male — 26 October 2026.