Peptide reconstitution calculator

Vial size, bacteriostatic water, your dose — the exact draw in insulin-syringe units. The same calculator that ships inside PeptideLab.

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Drawing with
Your vial

What’s in your vial?

Peptide in vial

From your 10 mg vial at 2 ml, you can dose 20× at 500 mcg.

How often?

This vial

20
doses of 500 mcg
—
cost per dose, once you add the vial cost

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peptidelabapp.com/calculator?vial=10&water=2&dose=500&syr=0.5

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Reconstitution
Compound
10 mg vial
Draw
10u
●Clean draw
Peptide10 mg
BAC water2 ml
Concentration5.00 mg/ml
Dose500 mcg
Syringe0.5 ml · U-100
Doses per vial~20
Draw volume
0.1 ml
peptidelabapp.com
Your biology. Your data. Your call.

In the app

Stop re-deriving this every week

  • Save it as a protocol — the draw is on every dose you log
  • Track the vial: doses left, discard window, when to reorder
  • Reminders, injection-site rotation, bloodwork trends

Reconstitution, explained

What is peptide reconstitution?+

Peptides ship as a lyophilized (freeze-dried) powder. Reconstitution is dissolving that powder in bacteriostatic water so it can be measured and drawn. How much water you add sets the concentration, and the concentration is what decides how many units on an insulin syringe equal your dose.

How many units is my dose?+

Divide the vial mass by the water volume to get the concentration in mg/ml. Divide your dose by that concentration to get the volume of one injection in ml. On a U-100 insulin syringe every 0.01 ml is one unit, so multiply that volume by 100. The calculator does exactly this and shows both steps.

How much bacteriostatic water should I add?+

More water gives larger, easier-to-measure draws; less water gives smaller draws that fit smaller barrels. 2 ml is the most common choice for a 5–10 mg vial. Pick the amount whose draw lands comfortably on your syringe's scale — the fit line under the result says when a draw is too fine to measure or too big for the barrel.

Does it work for injection pens?+

Yes. Switch the device to Pen and the calculator speaks pen: you set the dial's click size (1 unit on most reusable cartridge pens, ½ unit on half-unit models) and the pen's maximum per injection (30, 60, or 80 units). The result is the number to dial in the dose window, the calculator warns when a dose lands between clicks, and when a dose exceeds the pen's per-injection maximum it shows the split — or the water volume that gets it back to one injection.

What does U-100 mean?+

U-100 is the standard insulin syringe: 100 units per millilitre. It is what the units on the barrel are calibrated to. If you have a U-40 or U-500 barrel (rare, mostly veterinary), the unit markings mean something different and this calculator's unit readout will not apply.

Which peptides does it work for?+

Any lyophilized peptide — the math is the same regardless of the compound. The picker carries every compound the PeptideLab app lists for a protocol, and works out the draw for the 155 that come as powder: GLP-1s like semaglutide, tirzepatide and retatrutide, growth-hormone peptides, healing peptides like BPC-157 and TB-500, and more. Picking one sets the vial size and water it usually ships with. It never sets your dose. An oil like testosterone cypionate opens the ester calculator, which takes the concentration on its label.

Does it calculate peptide blends?+

Yes. Pick a blend from the peptide list, or switch to Blend, and the calculator handles a vial holding several peptides at once. Every blend on the list computes here, and you can build a vial the list doesn't have. You state your dose for the whole blend or for one compound in it, and every other component follows the ratio the vial was actually mixed at, so a 5:1:1:1 vial can't quietly hand you five times the dose you read.

Does this give medical advice?+

No. It performs arithmetic on numbers you enter. It does not recommend a dose, a compound, or a protocol, and it never pre-fills a dose for you. For medical decisions, consult a qualified healthcare professional.

Dosing from a pen? Pen calculator · Dosing a dog? Dog calculator · All calculators · For informational purposes only. This tool performs mathematical calculations and does not provide medical advice. Consult a healthcare professional for medical decisions. PeptideLab for iPhone and Android.