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Reconstitution & dose math

Peptide Calculator

Get your exact draw in U-100 syringe units, or how much bacteriostatic water to add. Free and instant.

U-100 syringe size

Draw

10units

on a 1.0 mL U-100 insulin syringe

0102030405060708090100
Volume
0.1 mL
Concentration
2.5 mg/mL
Doses per vial
20

This calculator only converts the numbers you enter. It does not choose a compound, dose, or schedule, and it is not medical advice. Nothing you type leaves your browser.

How peptide reconstitution math works

Every peptide calculator, including this one, runs the same three conversions. Nothing about them depends on the compound: the math is identical for any lyophilized peptide you reconstitute with bacteriostatic water.

  1. Find the concentration

    Multiply the vial contents by 1,000 to get micrograms, then divide by the water you added.

    (vial mg x 1,000) / water mL = mcg/mL

  2. Convert your dose to a volume

    Divide your dose in micrograms by that concentration to get the liquid volume of one dose.

    dose mcg / concentration mcg/mL = mL

  3. Convert the volume to syringe units

    A U-100 insulin syringe holds 100 units per milliliter, so multiply the volume by 100.

    dose mL x 100 = U-100 units

Worked example: 5 mg vial, 2 mL water, 250 mcg dose

  • 5 mg x 1,000 = 5,000 mcg, divided by 2 mL = 2,500 mcg/mL (2.5 mg/mL)
  • 250 mcg / 2,500 mcg/mL = 0.1 mL per dose
  • 0.1 mL x 100 = 10 units on any U-100 insulin syringe
  • 5,000 mcg / 250 mcg = 20 doses in the vial

How much bacteriostatic water should you add?

The amount of water never changes your dose, only how it reads on the syringe. More water means a larger, easier-to-read draw; less water means a smaller one. A practical approach is to pick a volume that lands your dose on a round number of units, which is exactly what the Reconstitute mode above works out for you.

Units measure volume, not peptide

On a U-100 syringe, 1 unit is 0.01 mL of liquid. The same 250 mcg dose can be 10 units in one vial and 25 units in another if they were reconstituted differently, so always recalculate when you mix a new vial. And watch the units of your plan: 1 mg equals 1,000 mcg, and mixing the two up is the most common dosing error.

Sources

This is the same math the Vitadel Protocol Tracker runs on your iPhone, where it also remembers your vials and logs every dose.

Peptide calculator FAQ

Water volumes, syringe units, and dose conversions explained.

Divide the vial contents (in mcg) by the water you added to get the concentration, divide your dose by that concentration to get milliliters, then multiply by 100 for U-100 syringe units. Example: a 5 mg vial in 2 mL of water is 2,500 mcg/mL, so a 250 mcg dose is 0.1 mL, which is 10 units.

Any amount you can measure works; the water only changes how large each draw is, never the dose itself. 2 mL is a common choice for a 5 mg vial because typical doses land on round unit counts (250 mcg = 10 units). Use the calculator's Reconstitute mode to find the exact volume that puts your dose on the units you want.

On a U-100 syringe, 100 units equal 1 mL, so 1 unit is 0.01 mL. Units measure liquid volume, not peptide amount: the same dose can be a different number of units depending on how the vial was reconstituted.

1 mg equals 1,000 mcg. Peptide plans mix both units freely (vials are usually labeled in mg while doses are often written in mcg), and confusing the two changes a dose by a factor of one thousand, so double-check which unit your plan uses.

Divide the vial contents by your dose in the same unit. A 5 mg (5,000 mcg) vial at 250 mcg per dose holds 20 doses. The calculator shows this automatically so you know when to reorder.

Yes. The reconstitution math is identical for any compound you mix from a lyophilized vial, including GLP-1s. GLP-1 doses are usually written in mg, so switch the dose unit toggle to mg and enter your plan's numbers.

No. The calculator runs entirely in your browser: nothing you type is stored, transmitted, or tracked. The Vitadel Protocol Tracker app works the same way, keeping your protocol on your iPhone by default.

Log your first dosein under a minute.

Vitadel Protocol Tracker does this math for you, logs each shot, rotates your injection sites, watches every vial, and tracks your macros from a snap of your plate. Private by default.

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