PT-141 reconstitution calculator

A 10 mg PT-141 vial mixed with 2 mL of bacteriostatic water gives 5 mg/mL. A 1.75 mg dose pulls 0.35 mL or 35 units — readable, repeatable. With on-demand dosing, the vial often outlasts the stability window.

In the worked example below, a 10 mg vial of PT-141 reconstituted with 2 mL of BAC water produces a concentration of 5 mg/mL. To draw the example dose of 1.75 mg from that vial you pull 0.35 mL — about 35 units on a standard insulin syringe. Change any input and the rest updates instantly so you can pre-plan a vial before you ever touch a needle.

Vial size, diluent volume, and dose are the three inputs that genuinely change the answer. Doses-per-vial is a derived output — it's the vial mg divided by the dose mg, rounded down. The most common edge case is a tiny dose: at very high concentration, a 0.1 mL draw is only a few units on the syringe, which is hard to read accurately. If your unit count drops below five, consider reconstituting the next vial with more BAC water so each dose covers a larger volume.

PT-141 typically comes as a lyophilized powder, which is a fancy term for freeze-dried. In this state, it’s stable, but it can’t be used. You first have to "reconstitute" it, which means mixing it with a sterile liquid to turn it back into a usable, injectable form. The liquid used for this is usually bacteriostatic water, which contains a small amount of benzyl alcohol to prevent any bacteria from growing in the vial. The process is simple but requires care. You gently inject the water into the vial of PT-141 powder, letting it run down the side of the glass rather than spraying it directly on the powder. Then, you slowly swirl the vial until all the powder is dissolved. You should never shake it, as this can damage the fragile peptide molecules.

Getting the math right is the most important part of reconstitution, as it ensures you know exactly how much PT-141 you are administering with each dose. Let's walk through a common example. You have a vial containing 10mg of PT-141 powder, and you are going to use 2mL of bacteriostatic water to reconstitute it. First, you need to find the concentration of your final solution. The math is straightforward: you divide the total amount of peptide by the total volume of water. So, 10mg of PT-141 divided by 2mL of water gives you a concentration of 5mg per 1mL.

Now that your solution has a concentration of 5mg/mL, you can figure out how much liquid to draw for your desired dose. Let's say you are planning to use an example dose of 1.75mg. To find the volume you need, you divide your desired dose by the concentration. So, 1.75mg divided by 5mg/mL equals 0.35mL. This means you need to draw 0.35mL of the solution into your syringe. Most people use a U-100 insulin syringe, where the markings are in "units." A 1mL syringe holds 100 units. To convert your volume to units, you simply multiply by 100. So, 0.35mL is equal to 35 units on the syringe. By carefully calculating and drawing 35 units, you can be confident you are administering exactly 1.75mg.