Dose calculator

PT-141 dose calculator

Convert any PT-141 dose into syringe units in real time, pre-filled with a 10 mg / 2 mL example.

iPhone · Free to download

Last updated: May 13, 2026

Vial (mg)

Diluent (mL)

Dose (mg)

Dose unit

Draw on a U-100 syringe

35.0 units

Volume to draw

0.350 mL

PT-141, also known as Bremelanotide, is a synthetic peptide that people use for its effects on sexual arousal. It was developed from a research chemical called Melanotan II but was designed to have more targeted effects on libido. Unlike other substances that work on blood flow, PT-141 is reported to work on the brain to increase sexual desire in both men and women. This page covers what PT-141 is, how people use it, and the common ways it is tracked in Peptide Pilot.

How the PT-141 dose calculator works

PT-141 (bremelanotide) is dosed on demand at 1.5-1.75 mg, not on a schedule. On a 10 mg vial mixed with 2 mL water (5 mg/mL), a 1.75 mg dose draws 35 units. The on-demand cadence makes vial-duration math different from peptides on a calendar.

The formula is volume in mL equals dose mg divided by concentration mg/mL, then volume times one hundred to get units on a U-100 insulin syringe. With a 5 mg/mL PT-141 solution and a 1.75 mg dose, the draw is 0.35 mL or about 35 units. Type any other dose and the unit count updates in real time — no spreadsheets, no guesswork.

Inputs that genuinely matter: concentration (which only changes when you reconstitute a new vial) and dose mass. Syringe type matters too, but only because U-100 vs U-40 changes the multiplier — almost every modern insulin syringe is U-100, which is why the math defaults to that. Edge cases worth flagging: switching from mcg to mg without checking the input unit, or carrying yesterday's unit count over to a new vial that was reconstituted with a different volume of BAC water.

Figuring out the right dose is a personal journey, and this Dose Calculator is a tool to help with the math, not the decision. The amount of PT-141 people use can vary widely based on individual factors like body weight, sensitivity, and desired effect. While research studies may explore a range of doses, finding what works for you often involves starting low and going slow. A common approach is to begin with a small test dose to see how you feel, and then adjust from there in later sessions. The calculator doesn't tell you how many milligrams to take, but once you've chosen an amount, it makes sure you can measure it accurately.

Think of this calculator as your personal math assistant for PT-141. Once you know the total mg in your vial (e.g., 10mg) and how much water you've added (e.g., 2mL), this tool does the heavy lifting. You just need to tell it what your target dose is in milligrams—for example, 1.75mg. It will then instantly calculate the exact volume of liquid you need to draw into your syringe. This removes the chance of making a manual calculation error and helps ensure your tracked doses are consistent and accurate, which is key to understanding your body's response over time.

Using this calculator helps standardize your process. Whether you're trying a small 0.5mg test dose or using a more standard 1.75mg dose, the math needs to be right every time. By using this tool, you can be confident that the dose you think you're taking is the dose you're actually taking. This precision is vital for effective tracking. It allows you to make meaningful comparisons between your log entries, so you can clearly see how different dose sizes affect your experience. It empowers you to fine-tune your protocol based on reliable data, not guesswork.

Worked example

Walking one PT-141 dose through the math

The vial holds 10 mg of PT-141, mixed into 2 mL of bacteriostatic water — concentration 5.00 mg/mL.
Your 1.75 mg dose ÷ 5.00 mg/mL = 0.350 mL of solution to pull.
Multiply by 100 (because U-100 means 100 units per mL): 0.350 × 100 = 35 units.
Double the dose to 3.5 mg and the unit count doubles to 70 — the relationship is linear at a fixed concentration.
Change the diluent volume and every one of these numbers moves; change the dose alone and only the last one does.

PT-141 titration ladder at this concentration

What different PT-141 dose steps draw on a U-100 insulin syringe at the example 5.00 mg/mL concentration.

Dose (mg)	Volume (mL)	Units (U-100)
0.875	0.175	17.5
1.75	0.350	35
3.5	0.700	70
7	1.400	140

Doubling the PT-141 dose doubles the unit count. Halving it halves the count. Step-ups under 5 units are hard to read accurately — re-reconstitute with more water if your titration hits that range.

Scenarios people actually run into

Three things that come up logging PT-141

You're sitting at the 1.75 mg PT-141 step and your prescriber bumps you up. The new dose is double — 70 units instead of 35. Same vial, same syringe, twice the volume on the line.
Your fingers reach for the syringe and the unit count from last week is still in your head. Half the time that number is fine; the other half, the vial changed and the right answer moved. The calculator is the second pair of eyes.
You skipped a week. PT-141 cadence is 2 doses per week, and doubling up to "catch up" almost never reads how people expect — log the skip, then log the next normal dose.

Same-category neighbor

PT-141 next to Semax

Both sit in the Sexual health bucket — here's the dose math side by side on each one's example vial.

	PT-141	Semax
Example dose	1.75 mg	0.4 mg
Concentration	5.00 mg/mL	2.50 mg/mL
Units to draw	35	16

Want the full breakdown? Semax reference →

How PT-141 dosing is tracked

The most common way people use PT-141 is on an as-needed basis, rather than following a strict daily or weekly schedule. This is because its effects are tailored to a specific event—sexual activity. A typical protocol involves administering a dose a few hours before it might be wanted. The timing can be crucial, as the effects are not immediate. Most users report that an optimal window is to take the dose about two to four hours prior to intimacy. This gives the peptide enough time to work its way through the system and for the effects on arousal to build to their peak. This event-based dosing makes PT-141 quite different from other peptides that might be used for recovery or metabolic health, which often require consistent, long-term administration to see results.

For newcomers to PT-141, a common practice is to start with a "test dose." This is a smaller-than-usual dose, perhaps 0.5mg or even less, to see how their body reacts. The primary reason for this is to check for sensitivity to side effects, especially nausea, which is the most common one reported. Based on the experience with the test dose, the user might then gradually increase the amount in subsequent sessions until they find what works for them. For some, a small dose is plenty, while others may find a higher dose like 1.75mg to be more effective. This process of titrating the dose based on personal experience is key to finding a sweet spot that maximizes the desired effects while minimizing any unwanted ones. Users often keep careful notes to dial in this personal amount.

The method of administration for PT-141 is typically a subcutaneous injection, which means it’s injected into the fatty layer of tissue just under the skin, often in the abdomen. The timing, as mentioned, is key. It’s not something to be taken in the heat of the moment. Planning ahead is part of the protocol. Because its effects can be long-lasting, sometimes even being felt the next day, it is generally advised to avoid redosing within a 24 to 48-hour period. Taking too much or too frequently doesn’t necessarily increase the positive effects but may increase the likelihood of side effects. This is why tracking each use, including the dose and timing, is so valuable for creating a successful and predictable experience.

The context of the dose can also matter. Some users report that taking PT-141 on an empty stomach can sometimes intensify feelings of nausea. For this reason, some prefer to take it after a small meal. However, a very large or heavy meal might slow down absorption. It’s a balance that each user has to find for themselves. Ultimately, the protocol for PT-141 is highly personal. It revolves around careful, single-event tracking and adjustment. By logging the dose, the timing, any side effects, and the quality of the experience, a user can build their own personalized protocol that aligns with their body and their an lifestyle.

Common PT-141 dose-calculation mistakes

Re-dosing within 24 hours of a previous dose.
Taking too high a dose the first time, leading to strong feelings of nausea.
Miscalculating the dose after reconstitution, leading to an incorrect amount.

Frequently asked questions about PT-141 dose calculator

How does the PT-141 dose calculator turn mg into syringe units?

It runs two divisions in sequence. First it computes concentration (vial mg ÷ diluent mL) — for the example here that's 10 ÷ 2 = 5.00 mg/mL. Then it divides your dose by that concentration to get volume in mL, and multiplies by 100 to convert volume into U-100 syringe units. The output updates as you type so you can sanity-check before drawing. PT-141 on-demand dosing is typically 30-60 minutes pre-event — log the timing alongside the dose for pattern visibility.

Does the PT-141 dose calculator know which syringe I'm using?

It assumes a U-100 insulin syringe — the most common type for sub-cutaneous peptide injections. U-100 means 100 units per mL. If you're using a U-40 syringe (rare outside veterinary contexts) the unit count is wrong by a factor of 2.5. Tuberculin syringes read in mL directly, so on those just use the volume figure. PT-141 on-demand dosing is typically 30-60 minutes pre-event — log the timing alongside the dose for pattern visibility.

Why does the same PT-141 dose pull a different unit count today than last week?

Because either the vial or the diluent volume changed. Concentration depends on both. A 5 mg vial reconstituted with 1 mL is twice as concentrated as the same vial with 2 mL — same dose, half the units. Whenever you open a fresh vial, run the dose math again rather than carrying the prior count over. PT-141 on-demand dosing is typically 30-60 minutes pre-event — log the timing alongside the dose for pattern visibility.

What if my PT-141 dose lands at fewer than 5 units?

That's the calculator telling you the current vial is too concentrated for the dose you want. Five units on a U-100 syringe is hard to read accurately — the markings get tight. Reconstitute the next vial with more bacteriostatic water (commonly 2 mL instead of 1 mL) so each dose covers a larger, cleaner volume. PT-141 on-demand dosing is typically 30-60 minutes pre-event — log the timing alongside the dose for pattern visibility.

Related on Peptide Pilot

Log every PT-141 dose in the app

iPhone · Free · No credit card