Peptide reconstitution calculator

How the math works

There are only three steps, and you can check the tool against them with a phone calculator in about ten seconds.

1. Concentration. Vial strength divided by the water you added. A 10 mg vial with 2 mL of bacteriostatic water is 10 / 2 = 5 mg/mL.
2. Volume. The amount you want divided by that concentration. 250 mcg is 0.25 mg, so 0.25 / 5 = 0.05 mL.
3. Syringe units. A U-100 insulin syringe reads 100 units to the millilitre, so multiply by 100. 0.05 x 100 = 5 units.

That last step is the one that catches people out. Units are not milligrams and they are not micrograms. They are a volume marking, and what one unit contains depends entirely on how much water went into the vial.

A few things worth knowing

• More water makes small amounts easier to measure. The same vial mixed with 1 mL instead of 3 mL puts the same amount at a third of the syringe marking, and a third of the room for error.
• Write the mix date on the vial. Reconstituted peptides have a much shorter shelf life than the lyophilised powder, and a month later nobody remembers.
• Check which syringe you are actually holding. U-100 and U-50 look similar and read differently. The barrel is printed with which one it is.
• Redo the math whenever the vial changes. A new vial strength, or a different amount of water, changes every number above.

Why I built this

I run my own protocol daily, and for the first few months my tracking was a mess of notes and a calculator app. The reconstitution math was the part I redid every time I opened a new vial, and got wrong more than once.

Pinwise is the iPhone app I built to stop doing this by hand. It keeps the concentration with the compound, so the syringe number is already there when you log a dose, and it keeps your history when the protocol changes. All the tracking is free, there is no account, and there is no backend, so there is no server holding your protocol. The Apple privacy label reads Data Not Collected.

Pinwise on the App Store