All compound calculators / Semaglutide
01Free · No signup · Runs in your browser
Semaglutide reconstitution calculator
Enter how much Semaglutide is in your vial and how much bacteriostatic water you added. The calculator works out the concentration, and converts whatever amount you type into units on a U-100 insulin syringe. It converts what you enter — it does not suggest, recommend or validate any amount.
02About Semaglutide
SemaglutideGLP-1
A GLP-1 receptor agonist, and a prescription medicine in the United States and the EU. Supplied both as a lyophilised powder in research vials, which has to be reconstituted, and as a ready-made solution in prescription pens, which does not.
03Handling and storage
Handling and storage
- Before it is mixed, a lyophilised peptide is a dry powder, and dry powder is the stable form. Once bacteriostatic water goes in, the clock starts — the solution is what degrades, not the powder.
- Add the water down the side of the vial and let it dissolve rather than shaking it. Peptides are large, fragile molecules; foaming is the visible sign that you were rough with one.
- Heat, light and freeze-thaw cycles are what shorten a reconstituted vial's life. Follow the storage and expiry guidance from your supplier or your clinician — this page cannot tell you how long your vial is good for.
04Questions
Questions
How much bacteriostatic water should I add to a Semaglutide vial?
That is your choice, and it changes only the concentration — never the total amount in the vial. More water spreads the same powder across more units on the syringe, which makes small amounts easier to read; less water means fewer units. Type your vial size and your water volume above and the calculator shows the concentration you would end up with.
How do I read the result in units?
A U-100 insulin syringe is marked in units, where 100 units is 1 mL. The calculator converts the amount you entered into millilitres first, then into those units, so the number it shows is the mark to draw to on that syringe. Check that the syringe in your hand is actually U-100 — U-40 syringes exist and the markings mean something different.
Does Semaglutide need to be reconstituted?
Only if you have it as a lyophilised powder. Powder has to be dissolved in bacteriostatic water before anything can be drawn from it. Anything already supplied as a solution does not get reconstituted, and this calculator is not the right tool for it.
Is this calculator free?
Yes. The reconstitution calculator on pepcoreapp.com stays free in any browser, with no signup, and it runs entirely on your device. The PepCore iPhone app is a separate subscription — $6.99/month or $39.99/year, with a 7-day free trial.
Stop redoing this math every vial
PepCore for iPhone saves the reconstitution per vial, tracks what is open and what expires when, logs every dose, and rotates injection sites on a body map. No account, no sign-in — your data stays on your device. Subscription with a 7-day free trial.