PT-141 is one of the few compounds on this site with a labelled dose, and the label states exactly one figure. Everything else in circulation, the 1 mg starting figure, the 2 mg ceiling, the nasal-spray milligrams, comes from somewhere other than the label, and this page says where. It then works the units for the 5 mg and 10 mg research vials the site's calculator uses.
PT-141 is bremelanotide, a seven-amino-acid cyclic melanocortin-receptor agonist derived from Melanotan II, approved in the United States as Vyleesi for hypoactive sexual desire disorder in premenopausal women. Medibact's PT-141 guide covers the molecule, its mechanism and its evidence; this page stays with figures. The dosage hub lists every compound's page, and Peptifact's PT-141 dosage page grades the same sources from a journalist's angle.
What the sources state
| Source | Kind | Figure | Date read |
|---|---|---|---|
| Vyleesi label, Cosette Pharmaceuticals (revised March 2024; DailyMed version published 2025-11-18) | Approved label | 1.75 mg subcutaneously, abdomen or thigh, as needed, at least 45 minutes before anticipated sexual activity; not more than one dose in 24 hours; more than 8 doses per month not recommended; 1.75 mg/0.3 mL single-dose autoinjector | 2026-09-18 |
| Kingsberg et al., Obstetrics and Gynecology 2019 (PMID 31599840), RECONNECT | Trial publication (phase 3) | 1.75 mg subcutaneously as needed versus placebo; 1,267 premenopausal women randomised | 2026-09-18 |
| Clayton et al., Womens Health 2016 (PMID 27181790) | Trial publication (phase 2b) | 0.75 mg, 1.25 mg or 1.75 mg self-administered subcutaneously; 327 women in the efficacy analysis; pooled 1.25/1.75 mg separated from placebo | 2026-09-18 |
| Safarinejad, Journal of Urology 2008 (PMID 18206919) | Trial publication (men, intranasal) | 10 mg bremelanotide as an intranasal spray; 342 men unresponsive to sildenafil | 2026-09-18 |
| Diamond et al., Journal of Sexual Medicine 2006 (PMID 16839319) | Trial publication (women, intranasal) | Single 20 mg intranasal dose; 18 women | 2026-09-18 |
| ClinicalTrials.gov search, "bremelanotide" | Registry | 10 records, phase 1 to 4, including NCT02333071 and NCT02338960 (the two phase 3 trials) and NCT06565611 (with tirzepatide for obesity, 2024) | 2026-09-18 |
| Vendor and protocol pages | Commonly cited | 1 mg start, 1.75 mg standard, 2 mg maximum, 45 to 60 minutes before activity; 10 mg vial with 2 mL; nasal spray "1 to 2 mg per actuation" | 2026-09-18 |
Two things stand out. Every subcutaneous trial dose is at or below 1.75 mg, and the label picked the top of the tested range. And the intranasal figures, 10 mg and 20 mg, are five to eleven times the injected dose, because they belong to a different route with different absorption; they do not transfer to a vial.
The one labelled figure
The label's arithmetic is its own: 1.75 mg in 0.3 mL is about 5.83 mg/mL, delivered by an autoinjector rather than drawn into a syringe. The label adds three limits that the trials produced. The 45-minute interval comes from the timing of the phase 3 protocol. The 24-hour limit and the 8-per-month limit come from the label's own safety data: focal hyperpigmentation appeared in 1% of patients at up to 8 doses a month, but in 38% of people given a dose every day for 8 days. The label also records a blood-pressure rise of up to 6 mmHg systolic and 3 mmHg diastolic, peaking 2 to 4 hours after a dose and usually gone within 12, and lists nausea (40%), flushing (20.3%), injection-site reactions (13.2%), headache (11.3%) and vomiting (4.8%) as the most common adverse reactions.
Units per dose at each research-vial size
Research-market PT-141 is supplied in 5 mg and 10 mg vials. The table takes each at 1, 2 and 3 mL of water, states the concentration, and converts the five figures in the record, 0.75 mg and 1.25 mg (phase 2b), 1 mg and 2 mg (vendor pages) and 1.75 mg (label and phase 3), into U-100 syringe units, where 100 units is 1 mL (MedlinePlus, "Giving an insulin injection", reviewed 2024-07-21, read 2026-09-18); the site's insulin syringe units page covers the syringe reading itself.
| Vial | Water added | Concentration | 0.75 mg | 1 mg | 1.25 mg | 1.75 mg | 2 mg |
|---|---|---|---|---|---|---|---|
| 5 mg | 1 mL | 5 mg/mL | 15 | 20 | 25 | 35 | 40 |
| 5 mg | 2 mL | 2.5 mg/mL | 30 | 40 | 50 | 70 | 80 |
| 5 mg | 3 mL | 1.67 mg/mL | 45 | 60 | 75 | 105 (>1 syringe) | 120 (>1 syringe) |
| 10 mg | 1 mL | 10 mg/mL | 7.5 | 10 | 12.5 | 17.5 | 20 |
| 10 mg | 2 mL | 5 mg/mL | 15 | 20 | 25 | 35 | 40 |
| 10 mg | 3 mL | 3.33 mg/mL | 22.5 | 30 | 37.5 | 52.5 | 60 |
Two consequences of the arithmetic. A 5 mg vial holds two of the labelled 1.75 mg amounts with 1.5 mg left over, and a 10 mg vial holds five with 1.25 mg left over, whatever the water volume, because the water changes the volume drawn and not the amount in the vial. And a 5 mg vial at 3 mL cannot deliver 1.75 mg in one 1 mL syringe, which is why vendor pages settle on 2 mL for a 10 mg vial. The PT-141 calculator works any combination entered, the site's PT-141 reconstitution page covers water volumes per vial and the mixing steps as references describe them, and the reconstitution chart lists the same concentrations for every compound.
What the figures omit
The label figure carries a population (premenopausal women with a diagnosed disorder), a route, a timing rule and two frequency limits. The trial figures carry the same population, or men with erectile dysfunction for the intranasal work, and a fixed schedule. The vendor figures carry none of that: they state a milligram amount and a timing window and are silent on population, on the monthly count, and on the hyperpigmentation data that produced the label's limit. None of the seven rows in the source table describes a course, a cycle or a duration, because the product is used per occasion; a "protocol" for PT-141 with days on and days off has no source in the record. Nothing in any row is a figure for men by the subcutaneous route: the men's trials were intranasal, and the label is for women.
Side effects as the sources report them
The label's figures are above. The phase 3 abstract names nausea, flushing and headache as the adverse effects that separated bremelanotide from placebo. The intranasal men's trial reported a 33.5% response against 8.5% on placebo and does not report adverse-event percentages in its abstract. This page does not add to those figures or reassure about them; the label's own warnings on blood pressure, on cardiovascular risk and on skin darkening are the record.
What this page does not do
This page reports figures with their sources and dates and converts them into syringe units at the site's vial sizes. It does not recommend a dose, a frequency or a route for anyone, does not say whether the label figure applies outside the labelled population, and does not turn the vendor range into advice. The reconstitution steps and the storage of a mixed vial are the store's topics: how to reconstitute peptides and how to store peptides on medibact.com.
Sources and dates
Opened 2026-09-18: the DailyMed SPL search for Vyleesi (one record, set id f1d0c1b5-2f39-4bad-a6a4-0066e3ad5dcf, published 2025-11-18) and the label itself (Dosage and Administration, Dosage Forms and Strengths, Warnings and Precautions, Adverse Reactions; revised March 2024); the ClinicalTrials.gov v2 API for "bremelanotide" (10 records); PubMed through the NCBI E-utilities for the abstracts of PMIDs 31599840, 27181790, 18206919, 18179455, 17958619 and 16839319; two vendor and protocol pages for PT-141 dosing and reconstitution; and MedlinePlus "Giving an insulin injection" for the U-100 definition. Corrections go to the contact page.