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Volume calculation · PT-141

PT-141 dosage calculator

This PT-141 calculator converts an amount into mL and syringe units. The Vyleesi preset describes a ready-filled device, not a powder to mix.

Vyleesi is a ready-filled autoinjector. This is its total liquid volume, not water to add. The syringe units compare volumes. They are not instructions to draw from or inject with that device.

Step 1 of 4

  1. How many mg are in the solution?
    Solution amounttotal mg in the calculation
  2. How many mL are in the solution?
  3. What dose do you want to convert?
  4. Which syringe are you using?
Calculated volume
30.0units

0.30 mL in the syringe · 1 calculated dose from this amount

30.0 units on a U-100 insulin syringe · 1 mL · lines every 2 units, which is 0.30 milliliters. The draw lands on a syringe line.

Easy to read on this syringe. The calculated volume matches the 30-unit line. No rounding is needed.

1.75 mg ÷ 0.3 mL = 5.83 mg/mL
→ 58 mcg/unit · 1.75 mg = 0.300 mL = 30.0 units

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Show the math and syringe details

Can this syringe show the result clearly?

Easy to read on this syringe. 30.0 u is exactly the 30-unit line on a U-100 — no rounding error at all.

This setup is in the address bar — every input is part of the link.

Educational math, not medical advice — dosing decisions belong to a licensed clinician.

How to use the calculator

  1. 1

    Enter the total amount

    Use the total PT-141 amount in mg for this calculation.

  2. 2

    Enter the total solution volume

    Use the total volume of the finished solution, in mL. This is not water to add.

  3. 3

    Enter the dose you want to convert

    Choose mg or mcg, then match the result to your syringe.

PT-141 is the development code for bremelanotide. It acts on melanocortin receptors in the brain, rather than on blood flow the way the erectile-dysfunction pills do. It is bought mostly by men, for erections and desire.

That is the one group its label rules out. Vyleesi was approved in 2019 for premenopausal women with low sexual desire. The same label excludes postmenopausal women, and use to improve sexual performance. In the trials behind it, 18% of participants stopped because of a reaction.

Examples using 1.75 mg of PT-141

Each row uses 1.75 mg and the liquid volume shown. Dividing the amount by that volume gives the calculated concentration. The rows are arithmetic examples, not alternative product preparations.

◆ How liquid volume changes the resultdose used: 1.75 mg

With 0.3 mL total solution volume

30.0 units

Starting example
Concentration
5.83 mg/mL
Each U-100 unit
58.3 mcg
Syringe volume
0.300 mL
Nearest line
Exactly 30 units

The amount, liquid volume and dose shown here are the calculator’s starting example for PT-141. Replace them with your own values. Every result in the table is calculated from those inputs.

Vyleesi is a ready-filled injector, not a powder to mix

PT-141 is another name for bremelanotide. Its approved product, Vyleesi, contains a ready-made solution in a single-dose autoinjector. The amount and volume used in these presets mirror that fill. The volume is not water to add to a powder vial.

Open the mixing details3 notes

The preset describes a finished solution

Vyleesi comes as a liquid in its own device. Its label has no powder-mixing step. Entering that liquid’s amount and volume gives its strength in mg/mL. It does not tell you how to make it.

A powder described as PT-141 is not the approved autoinjector. A matching mass cannot establish the same formulation, mixing instructions or delivery. The calculator does not turn one product into the other.

One calculated dose does not verify delivery

The default amount equals the amount in the preset, so dividing one by the other gives one dose. That is a mass calculation. It is not a measurement of what any device delivers.

The tool cannot measure liquid left in a container or needle, and it has no measured allowance for those losses. A syringe-unit result is also not an instruction to withdraw solution from the Vyleesi device or change its fill.

As-needed use is not a repeating course

Vyleesi’s label describes as-needed use with limits on how often it can be repeated. A fixed weekly interval entered into a supply tool does not represent that label schedule.

A dose count cannot predict when an as-needed medicine will next be used. It also cannot establish a storage period for a separately mixed product. The ready-filled device’s instructions and any hypothetical powder calculation remain different things.

Vyleesi arrives as a ready-made solution

PT-141 is the development code for bremelanotide, the ingredient in Vyleesi. The approved product is a single-dose autoinjector. Its label does not describe reconstituting a powder vial, even when the ingredient name matches.

Read the supporting evidence3 supporting notes

The label’s fill volume belongs to the autoinjector

The labeled amount and liquid volume describe that prepared product. They do not identify the concentration of another vial. The tool needs the actual strength and volume entered for the preparation being calculated.

As-needed use still has timing limits

The label limits how often Vyleesi is used within a day and a month. It also states when treatment should stop if symptoms do not improve. A volume calculation does not track those limits.

A repeated-dose curve would answer the wrong question

An as-needed medicine is not the same as a fixed daily course. The tool does not turn the label’s dose into a titration ladder or infer a personal schedule from how much remains in a vial.

Units to dose at 5.83 mg/mL

Mix 1.75 mg into 0.3 mL and one U-100 unit carries 58.3 mcg. The table shows how much peptide is in each numbered syringe line. These are conversion examples, not suggested doses.

Open the unit conversion table10 rows
Numbered U-100 syringe lines converted to volume and mass at 5.83 milligrams per milliliter.
U-100 lineVolumeMass (mcg)Mass (mg)
10 u0.10 mL583 mcg0.583 mg
20 u0.20 mL1,167 mcg1.167 mg
30 u0.30 mL1,750 mcg1.75 mg
40 u0.40 mL2,333 mcg2.333 mg
50 u0.50 mL2,917 mcg2.917 mg
60 u0.60 mL3,500 mcg3.5 mg
70 u0.70 mL4,083 mcg4.083 mg
80 u0.80 mL4,667 mcg4.667 mg
90 u0.90 mL5,250 mcg5.25 mg
100 u1.00 mL5,833 mcg5.833 mg

How the math works

  1. Concentration — divide the amount entered by the liquid volume used in the calculation: mg ÷ mL = mg/mL. This tells you how many mg are in each mL.
  2. Volume — the dose divided by that concentration: dose ÷ (mg/mL) = mL.
  3. Units — on a U-100 syringe one unit is 0.01 mL, so mL × 100 = units. A U-40 unit is 0.025 mL, so the wrong barrel is a 2.5× error. That is why the calculator asks which one you have.
  4. Rounding gap — the exact draw against the nearest syringe line: |exact − nearest line| ÷ exact × 100 = % difference.

Medically reviewed by Kenneth Montecillo, MD2026-09-07open the primary sources

Useful guides for this calculation

The math is only one part of the question. These guides cover the compound, published doses, side effects, mixing steps and supplies.

PT-141 research, dosing, and approval status

PT-141 has an FDA-approved use and prescribing label.

PT-141 side effects, as the sources describe them

When PT-141 reactions tend to appear, tied to that compound’s own escalation steps.

The 1.75 mg PT-141 vial: concentrations and example draws

A 1.75 mg PT-141 vial and a differently sized one are genuinely different arithmetic.

Mixing math for any vial, not just PT-141

One calculator for every vial on this site, with PT-141 as one example

What the PT-141 draw needs from bacteriostatic water

What a label allows, stated for bacteriostatic water rather than for PT-141.

The Hospira vial for a PT-141 vial

The Hospira vial is the second thing the PT-141 calculator asks you for.

Questions readers ask

How much BAC water do you mix with PT-141?

The approved product is never mixed. Vyleesi arrives as a filled autoinjector holding 1.75 mg in 0.3 mL of solution, and nothing in its label is reconstituted.

This page mirrors that fill, so its one preset is 1.75 mg in 0.3 mL, or 5.83 mg/mL. At that strength the whole vial is a 30 unit draw. Any other volume is your choice rather than a label’s.

How many units of PT-141 should I take?

The label sets one fixed quantity, 1.75 mg, which on this page’s mixing is 30 units. It caps use at one dose in 24 hours and advises against more than 8 doses a month.

That quantity belongs to one group: premenopausal women with acquired, generalized hypoactive sexual desire disorder. The label rules the drug out for men, for postmenopausal women, and for enhancing sexual performance. A powder vial matching the milligrams is still not the approved product.

Where is the best place to inject PT-141 peptide?

The label names two places and ranks neither: under the skin of the abdomen, or of the thigh. It sets the timing at least 45 minutes before anticipated sexual activity.

No published comparison puts one site above the other, so nobody can honestly call one best. The label does rule the drug out entirely in uncontrolled high blood pressure or known heart disease.

How much water to reconstitute 10 mg of peptide?

For any peptide the shape is identical: pick a volume, and the strength is the milligrams divided by it. 10 mg in 1 mL is 10 mg/mL, so one U-100 unit holds 100 micrograms. 2 mL halves that to 50.

10 mg is also nearly six times what this page’s vial holds. That gap matters more than the arithmetic. A vial holding one labeled dose and a vial holding many are different objects with different questions.

1primary source, each with the day we read it — open the documents used on this page