PT-141 is bremelanotide, and the search for its dosage splits by sex because the record does. The one approved product, Vyleesi, sets a single 1.75 mg dose for one group: premenopausal women with acquired, generalized hypoactive sexual desire disorder. Men appear only in an earlier development programme for erectile dysfunction, at higher doses and partly by nasal spray, which ended without an approval. This page sets the two side by side, from the label and the studies opened on 2026-10-27, and converts both into syringe units. It reports; it recommends no dose for anyone.
The compound's full figures are on the PT-141 dosage page, and the nasal route on PT-141 nasal spray.
The record by sex
| Women | Men | |
|---|---|---|
| Approved use | Vyleesi: premenopausal women, acquired generalized HSDD | None; the label states "not indicated … in men" |
| Labelled dose | 1.75 mg subcutaneous, as needed, ≥45 min before activity | — |
| Label limits | ≤1 dose per 24 h; ≤8 doses a month; stop after 8 weeks without improvement | — |
| Doses studied | 0.75, 1.25, 1.75 mg subcutaneous (phase 2b); 1.75 mg (phase 3) | 0.3–10 mg subcutaneous (healthy men); 4 or 6 mg (erectile dysfunction); 7.5 mg and 10 mg intranasal |
| Size of the record | Phase 2b with 327 in the efficacy analysis; two phase 3 trials, 1,267 randomised | Phase 1/2 laboratory studies; one 19-man crossover; one 342-man trial with a 2023 expression of concern |
| What was measured | Desire score, distress score, satisfying sexual events per month | Erections by RigiScan; erectile-function questionnaire |
| Publication years | 2016–2019 | 2003–2008 |
The two programmes did not measure the same thing. The women's trials ask whether desire and its related distress change over 24 weeks; the men's studies ask whether a single dose produces an erection in the hours after it.
Women: how 1.75 mg was chosen
The phase 2b trial randomised premenopausal women to placebo or 0.75, 1.25 or 1.75 mg, self-injected as desired for 12 weeks. Pooling 1.25 and 1.75 mg against placebo, satisfying sexual events rose by 0.7 a month against 0.2, with nausea, flushing and headache the reported adverse events. The phase 3 RECONNECT trials then tested 1.75 mg alone for 24 weeks in 1,267 women, mean age 39, 96.6% at US sites: desire scores rose by 0.30 and 0.42 points more than placebo, and nausea, flushing and headache each occurred in 10% or more. The label's per-day and per-month caps follow from blood pressure and pigmentation: it states that doses close together "may increase the risk of additive effects on blood pressure" and that more frequent use raises the risk of focal hyperpigmentation.
Men: the development programme
The early studies gave men PT-141 subcutaneously from 0.3 to 10 mg, with a measurable erectile response above 1.0 mg, and then 4 or 6 mg to men with erectile dysfunction who responded poorly to sildenafil (Rosen 2004). A nasal spray followed: 7.5 mg with a sub-therapeutic 25 mg of sildenafil in 19 men (Diamond 2005), and 10 mg in 342 men who had not responded to sildenafil, reporting a positive result in 33.5% against 8.5% on placebo (Safarinejad 2008). The 2008 paper carries a 2023 expression of concern from the journal, so its figures are reported with that flag. Development for erectile dysfunction did not lead to an approval; the later programme and the approval were in women. A 2026 review of peptides in sexual medicine describes bremelanotide as having "defined dosing and regulatory approval for selected indications" and lists no male indication (Sex Med Rev 2026, PMID 42862021).
Why the numbers are not comparable
The men's figures span two routes, subcutaneous and intranasal; the nasal doses are the largest, and how much of a nasal dose reached the blood is not reported in the abstracts read. The endpoints differ as well. No study gave men and women the same dose and compared them, so "the men's dose is higher" describes what was tested, not a finding that men need more. Kisspeptin, the other peptide often searched alongside it, is compared on kisspeptin vs PT-141.
The amounts, as syringe units
Units on a U-100 syringe = milligrams ÷ concentration in mg/mL × 100. Research vials are 10 mg; the Vyleesi autoinjector is a fixed 1.75 mg in 0.3 mL and is never mixed.
| Amount | 10 mg/mL | 5 mg/mL | 3.33 mg/mL | 2.5 mg/mL |
|---|---|---|---|---|
| 0.75 mg (phase 2b, women) | 7.5 units | 15 | 22.5 | 30 |
| 1.25 mg (phase 2b, women) | 12.5 | 25 | 37.5 | 50 |
| 1.75 mg (label, women) | 17.5 | 35 | 52.5 | 70 |
| 4 mg (study, men) | 40 | 80 | — | — |
| 6 mg (study, men) | 60 | — | — | — |
Concentrations: 10 mg/mL is a 10 mg vial with 1 mL of water, 5 mg/mL with 2 mL, 3.33 mg/mL with 3 mL, 2.5 mg/mL with 4 mL. A dash marks a draw larger than one 100-unit syringe. The PT-141 vial arithmetic works any vial and volume, and the mixing figures are on PT-141 reconstitution.
What is not established
Any dose for men: none is approved and the studies that tested one ended by 2008. Any dose for postmenopausal women: the label excludes them. A direct comparison of the sexes at one dose: never run. Medibact's PT-141 guide covers the compound. Decisions about whether to use it belong with a clinician.
Sources and dates
Opened 2026-10-27: the openFDA record of the VYLEESI label (set id f1d0c1b5-2f39-4bad-a6a4-0066e3ad5dcf, effective 2025-11-13), sections 1 and 2; the abstracts of PMIDs 27181790, 31599840, 14999221, 15833522, 18206919 and 42862021 and the PubMed record listing the 2023 expression of concern on 18206919, through NCBI E-utilities; the ClinicalTrials.gov v2 API search for bremelanotide (10 records, with sex eligibility and enrolment). Unit arithmetic by this site. Corrections go to the contact page.