Peptide Reconstitution Calculator
Enter how much peptide is in the vial, how much bacteriostatic water you're adding and the dose you need. You get the exact mark on the syringe, the vial's concentration and how many doses it holds.
Water doesn't change the dose — it changes how many units the dose takes up.
U-100 and U-50 share the same scale — 100 units per mL. The U-50 just has half the barrel (0.5 mL), so it stops at 50. The U-40 marks 40 units per mL, which is a different scale. Check what's printed on yours.
Fill in the vial, the water and the dose to see the result.
Personal journal. Not medical advice.
How reconstitution math works
Three steps, none of which depend on the peptide: concentration, volume, units. Each one below is solved with the values sitting in the calculator.
Concentration
Milligrams in the vial ÷ mL of water = how many mg sit in each mL.
vial ÷ water = concentration10 mg ÷ 2 mL = 5 mg/mLVolume per dose
Dose ÷ concentration = how many mL you need to draw.
dose ÷ concentration = mL1 mg ÷ 5 = 0.2 mLUnits on the syringe
mL × 100 on a U-100 or U-50 syringe (or × 40 on a U-40) = the mark to stop at.
mL × 100 = units0.2 mL × 100 = 20 unitsThe whole thing in one formula
units = dose ÷ (vial ÷ water) × 100Vial in mg, water in mL, dose in mg. The 100 covers U-100 and U-50; swap it for 40 if your syringe is a U-40.
A 10 mg vial with 2 mL of water gives 5 mg/mL. A 1 mg dose takes up 0.2 mL — that's 20 units on a U-100 syringe.
The conversions people look up
What's the peptide reconstitution formula?
units = dose ÷ (mg in vial ÷ mL of water) × 100. The 100 becomes 40 if your syringe is a U-40.
How many units is 1 mg in a 10 mg vial with 2 mL?
20 units on a U-100. The concentration is 5 mg/mL and the dose takes up 0.2 mL.
How do I convert mL to syringe units?
Multiply by 100 on a U-100 and by 40 on a U-40. 0.2 mL is 20 units or 8 units respectively.
Do I have to redo the math for every vial?
Whenever the amount of water changes. The same vial with the same dose, diluted differently, gives a different mark.
Units by dose and dilution
A 10 mg vial on a U-100 syringe. Columns are the water you used to reconstitute.
| Dose | 1 mL | 2 mL | 3 mL | 5 mL |
|---|---|---|---|---|
| 0.25 mg | 2.5 | 5 | 7.5 | 12.5 |
| 0.5 mg | 5 | 10 | 15 | 25 |
| 1 mg | 10 | 20 | 30 | 50 |
| 2.5 mg | 25 | 50 | 75 | 125 |
| 5 mg | 50 | 100 | 150 | 250 |
What reconstitution actually changes
Peptides arrive lyophilized: a dry, almost invisible powder at the bottom of the vial. Reconstituting means dissolving that powder in bacteriostatic water so it becomes injectable. The amount of water doesn't change how much peptide is in there — it changes the concentration, and with it how many marks your dose takes up on the syringe.
That's where the confusion comes from. The same 1 mg can be 10 units in one vial and 40 in another, purely because the water was different. So the math has to be redone with every new vial — and memorizing “my dose is 20 units” is one of the easiest ways to get it wrong.
Rule of thumb: more water makes the reading more comfortable, because the same dose spreads across more marks. Less water concentrates it and fits more dose into a single injection. The sweet spot usually sits between 10 and 50 units — big enough to read by eye, small enough to fit in the syringe.
Do this math once. Once.
In PepPro you enter the vial and the water a single time. From then on the app works out every injection on its own, shows the units on a visual syringe, reminds you at the right moment and keeps the whole history.
- Your reconstitution stays saved per vial
- Exact units on a visual syringe before you inject
- Reminders, titration and injection-site rotation
- Full history of doses, weight and how you feel
Exact units on a visual syringe before you inject
Good question. We've got answers.
Didn't find what you were after? Email us at contato@upsidecompany.com.br.
There's no single right number: any volume that dissolves the powder works, and the dose stays the same. What changes is the reading. Anything from 1 mL to 3 mL covers most vials — pick the one that lands your dose between 10 and 50 units, which is the easiest range to hit by eye.
Bacteriostatic water contains benzyl alcohol, a preservative that holds back contamination once the stopper has been punctured several times. Sterile water has no preservative and is meant for single use. For a vial you'll use over weeks, bacteriostatic is the standard.
No. 1 mg is still 1 mg whether you used 1 mL or 3 mL of water. What changes is the volume you draw — and therefore the number of units on the syringe. That's exactly why the calculation needs the water as an input.
U-100 and U-40 are different scales: on a U-100, 100 units equal 1 mL; on a U-40, 40 units equal 1 mL. The same dose produces very different numbers on the two. A U-50 isn't a third scale — it's a half-millilitre U-100: the same 100 units per mL, in a barrel that only reaches 50. Check what's written on yours before drawing anything.
It depends on the peptide, the water used and how it's stored. The standard is refrigerated, protected from light, and following the expiry your manufacturer or healthcare professional gives you. If the solution turns cloudy or shows particles, don't use it.
Yes — that's exactly what PepPro is for. Enter the vial and the reconstitution once and the app takes over: it works out every injection, shows the units on a visual syringe, reminds you when it's time and keeps the history of doses, weight and how you feel.
No. PepPro is a personal journal and this calculator is an educational tool. Nothing here replaces a qualified healthcare professional — they're the one who decides whether, how much and how you should use any compound.
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Personal journal. Not medical advice.
Disclaimer
This calculator is for informational and educational purposes only and is not medical advice. Always confirm dosing with a qualified healthcare professional and double-check your own measurements before administering anything.