PT-141 (Bremelanotide) Dosage Calculator

PT-141 units chart for 5 mg and 10 mg vials

All figures are units on a U-100 insulin syringe. Find your vial and water on the left, then read across. The amounts across the top show how the arithmetic scales. 1.75 mg is included because it is the amount in the approved product, not as a suggestion.

Two rows give the same answers: 10 mg in 2 ml and 5 mg in 1 ml are both 5 mg/ml. What sets the mark is the concentration, not the vial size. The 5 mg + 2 ml row shows the other side of that: at 2.5 mg/ml, 2 mg is 80 units, close to the top of a 100 unit syringe and too much for a 50 unit one.

Units measure liquid, not PT-141

An insulin syringe unit is a volume: 1 unit is 0.01 ml. It says nothing about how much PT-141 is in that liquid. The same 1.75 mg is 17.5 units at 10 mg/ml, 35 units at 5 mg/ml and 52.5 units at 3.33 mg/ml. Three different marks, one amount.

The approved autoinjector makes the point well. It holds 1.75 mg in 0.3 ml, a concentration of about 5.83 mg/ml. That 0.3 ml is the same volume as 30 units on an insulin syringe, yet a 10 mg vial mixed with 2 ml needs 35 units to hold the same 1.75 mg. Copying a number of units from someone else only works if their vial and water match yours exactly.

So write the concentration on the vial when you mix it. If the label says “10 mg / 2 ml = 5 mg/ml”, any amount converts in one step: milligrams ÷ 5 × 100 = units.

How much bac water to add to a 10 mg vial

There is no single correct volume. The choice is a trade between how readable the marks are and how much liquid each draw takes. 2 ml is the common pick because it lands on a round 5 mg/ml, where 0.1 mg is exactly 2 units and the mental arithmetic stays simple.

1 ml makes everything twice as concentrated. A 0.5 mg draw becomes 5 units, a short distance on the barrel where a small misread is a large share of the amount. 3 ml goes the other way: marks get bigger, but the concentration is 3.33 mg/ml, so the units stop being round numbers. If you change your mind later, you cannot take water back out; you can only work with the new concentration.

Bac water is sterile water with a preservative, which is what lets a mixed vial be used more than once. It has its own time limit after opening: how long bac water lasts.

What the approved bremelanotide label says

Unlike most compounds sold as research peptides, bremelanotide also exists as an FDA-approved medicine, so there is an official label to read. Vyleesi's prescribing information (revised March 2024) states:

• Who it is for: premenopausal women with acquired, generalised hypoactive sexual desire disorder. Not indicated for men or postmenopausal women, and not indicated to enhance sexual performance.
• Dose and timing: 1.75 mg under the skin of the abdomen or thigh, at least 45 minutes before expected sexual activity.
• Limits: no more than one dose in 24 hours; more than 8 doses a month is not recommended.
• Blood pressure: each dose briefly raises blood pressure and lowers heart rate. It must not be used with uncontrolled high blood pressure or known heart disease.
• Common side effects in trials: nausea (40% of patients), flushing (20%) and headache (11%).

These facts describe the approved product, in the population it was tested in. They are here so you know what the official source says, not as a schedule for research powder, which has no such review behind it.

Questions

How many units is 1 mg of PT-141?

It depends on the water. In a 10 mg vial mixed with 2 ml of bac water the solution is 5 mg/ml, so 1 mg is 0.2 ml, which is 20 units on a U-100 insulin syringe. With 1 ml of water the same 1 mg is 10 units, and with 3 ml it is 30 units. Enter your own vial and water above to get your exact mark.

How much bac water for 10 mg of PT-141?

Most people use 1, 2 or 3 ml. 2 ml gives a round 5 mg/ml, where every 0.1 mg is 2 units. 1 ml gives 10 mg/ml and halves every draw, which makes small amounts hard to read. 3 ml gives 3.33 mg/ml, a less tidy number but bigger, easier marks. The water does not change how much PT-141 is in the vial, only how much liquid each milligram takes up.

What is the PT-141 dosage?

The only dose a regulator has reviewed is on the label of Vyleesi, the approved bremelanotide product: 1.75 mg injected under the skin of the abdomen or thigh, at least 45 minutes before expected sexual activity, no more than one dose in 24 hours, and more than 8 doses a month is not recommended. That label covers the approved autoinjector for one specific group of patients. Research vials sold as 'PT-141' are not Vyleesi, and this page does not suggest a dose.

Is there a PT-141 dosage for men?

Not an approved one. Vyleesi is approved only for premenopausal women with acquired, generalised hypoactive sexual desire disorder, and its label says it is not indicated for men or for postmenopausal women. No regulator has reviewed a dose for men. The syringe arithmetic is the same for anyone: units depend only on the milligrams in the vial, the water and the amount you enter.

Is PT-141 the same as bremelanotide and Vyleesi?

PT-141 is the old development code for bremelanotide, a melanocortin receptor agonist. Vyleesi is the brand name of the FDA-approved bremelanotide injection, approved in 2019. The molecule is the same, but the products are not: Vyleesi is a ready-to-use 1.75 mg autoinjector made under drug manufacturing rules, while 'PT-141' powder sold online is typically labelled for research use only.

Do I need a calculator for the Vyleesi autoinjector?

No. The autoinjector holds one fixed 1.75 mg dose in 0.3 ml and delivers all of it, so there is nothing to mix or measure. The calculator is only for powder vials that you mix with water yourself.