Peptide reconstitution questions and answers
Short answers to common peptide reconstitution questions. Every number is worked out the same way as the peptide calculator. For word meanings, see the glossary.
Questions about using the calculator
What does a peptide reconstitution calculator do?
It turns your vial amount, water volume and dose into the number of units to draw on an insulin syringe. It first works out how strong the mixed vial is (the concentration), then how much liquid holds your dose, then where that volume sits on the syringe scale.
Does the calculator recommend doses?
No. The calculator only does the math for a dose you enter. It never suggests a dose for any product or condition. Ask a qualified healthcare professional about dosing.
Why does the calculator warn when a dose is under 2 units?
Very small amounts are hard to measure accurately by eye. If your dose is under 2 units, adding more water when you mix the vial makes the same dose take up more units, which is easier to read.
Why does the calculator say my dose is more than the vial?
Usually because mg and mcg are mixed up. 1 mg is 1,000 mcg, so a dose typed in mg while you meant mcg is 1,000 times too big. Check the unit next to the dose and the vial.
Peptide reconstitution questions about the math
How do I calculate peptide concentration?
Divide the amount of peptide in the vial by the water you added. A 5 mg vial mixed with 2 mL of water holds 2,500 mcg per mL. At that strength, a 250 mcg dose is 10 units on a U-100 syringe.
Does adding more water change the dose?
No. More water spreads the same amount of peptide through more liquid, so each unit holds less and you draw more units for the same dose. A 5 mg vial mixed with 2 mL of water holds 2,500 mcg per mL, while a 5 mg vial mixed with 3 mL of water holds 1,666.67 mcg per mL.
How many doses are in a vial?
Divide the amount in the vial by your dose and round down. A 5 mg vial holds 20 doses of 250 mcg. The calculator shows this as "Full doses in vial".
Questions about syringes and units
What does U-100 mean on a syringe?
It tells you how many units fit in 1 mL. U-100 means 100 units fill 1 mL, so each unit is 0.01 mL. U-40 means 40 units fill 1 mL, so each U-40 unit is a bigger volume.
What size syringe should I use?
Use the smallest syringe that holds your whole dose, because smaller syringes have finer marks. A 0.3 mL U-100 syringe holds 30 units and is often marked every half unit. A 0.5 mL U-100 syringe holds 50 units, and a 1 mL U-100 syringe holds 100 units with a line every 2 units.
Can I use a U-40 or U-50 syringe with this calculator?
Yes. Choose the syringe type under "Syringe type" and the calculator uses the right scale. Never use U-100 numbers on a U-40 syringe, because the same number of units is a different volume.
Questions about water
What is bacteriostatic water?
Bacteriostatic water is sterile water with 0.9% benzyl alcohol added. The benzyl alcohol slows the growth of bacteria, which is why it is used for vials that are opened more than once.