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Peptide Reconstitution Calculator

Calculate how much bacteriostatic water to add to your peptide vial, the resulting concentration, how much to draw in your syringe, and how many doses you'll get per vial.

Interactive calculatorLive lab data

1Your vialNew · use the lab-measured amount

How many mg is on the label?

mg
Have the lot number? We’ll use what the lab measured instead of the label.

2Water

Bacteriostatic water — not sure how much? Let the calculator pick.

mL
The size of the glass bottle — not the mg on the label. Small peptide vials often hold only 2–3 mL.

3Your dose

How much per shot?

250 mcg = 0.25 mg

4Which syringe do you have?

Pick the one in your hand.

Not sure? Look at the biggest number printed on the barrel — 30, 50 or 100.

Check the box says U-100. Syringes for pet insulin (U-40) look the same but their lines measure 2.5× more liquid. This calculator is for U-100 syringes only.

Peptide (optional)

Look up its tested purity on Peptigrity

1
First, add to the vial
2.4mL of water
2
Then, each dose: pull the plunger back to
6units
on your 1 mL syringe · 0.06 mL · one 250 mcg dose
Why 2.4 mL? So each 250 mcg dose lands on the 6 line of your 1 mL syringe, and the water fits a vial up to 3 mL.
Rounder with a 0.3 mL syringe: 2 mL, draw to 5.
How we pick the water
  1. It fits your vial, and it’s at least 1 mL.
  2. One dose fits one syringe and is at least 5 units.
  3. The dose lands on a line of your syringe.
  4. If the amount this calculator starts with already does that, we keep it.
  5. Otherwise: whole mL first, then half, then 0.1 mL steps.
  6. A numbered line if possible, 10 to 50 units if possible.
  7. Easy math: 10 units come out as a round number.
  8. Less water, if it’s still a tie.
We only pick the water. The dose is always yours.
Lands on the 6 line.
Close-up of your syringeblack numbers are printed on the syringe · gray ones are our count
024681012141618202224Line up this edge with 6the edge of the black stopper nearest the needle
The whole syringe1 mL · a line every 2 units
1020304050607080901006

Each line on this syringe = 2 units = 83.3 mcg.

First, mix the vial: add 2.4 mL of water
With the syringe you picked, fill your 1 mL syringe to 100 and empty it into the vial twice, then once more to 40.
Each unit holds
41.7 mcg
Doses in this vial
40
Mixed strength
4.17 mg per mL

Easy check: 10 units = 416.7 mcg · 20 units = 833.3 mcg

Educational tool for research use. Not medical advice — it calculates what you enter, it doesn't recommend a dose.

How to Use This Calculator

  1. Enter vial size - the amount of peptide in your vial in milligrams (mg). Common sizes: 5mg, 10mg.
  2. Enter BAC water volume - how many millilitres of bacteriostatic water you want to add. The vial on the right fills as you change it.
  3. Enter desired dose - how many micrograms (mcg) you want per administration.
  4. Choose syringe type - this determines how many units to draw on your syringe markings.
  5. Select your peptide (optional) - this will show the average purity from lab tests on Peptigrity.

What Is Peptide Reconstitution?

Peptide reconstitution is the process of dissolving a lyophilized (freeze-dried) peptide powder with a sterile solvent - typically bacteriostatic water (BAC water). This creates an injectable solution at a known concentration, allowing you to measure precise doses using an insulin syringe.

BAC water contains 0.9% benzyl alcohol as a preservative, which allows the reconstituted solution to remain stable for approximately 28 days when stored at 2-8°C (refrigerated). Sterile water without preservative should be used within 24-48 hours. For the full calculator with presets for every peptide on the site and a protocol planner, see the peptide calculator.

Related tools

6 calculators
Peptide Calculator
Select a peptide, enter vial size and BAC water volume, and get exact syringe units, concentration, doses per vial, and protocol cost. Covers every peptide on the site — presets for the common ones, custom mode for the rest.
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BAC Water Calculator
Calculate exactly how much bacteriostatic water you need based on vial size, target strength, and syringe type. Use this before reconstituting.
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Cost-per-Dose Calculator
Cost per dose, per week and per month from the vial price you paid, with the live lowest and median $/mg across shops for your compound.
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Purity Comparison Tool
Compare tested purity across brands with the spread of results and measured quantity vs label, from the lab database.
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Blend Calculator
Dose multi-peptide blend vials (GLOW, KLOW, CJC/Ipa, Wolverine, custom). One draw, every component's dose shown.
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Reverse Calculator
Convert syringe units back to mg/mcg, or find the BAC water volume for a target strength. Verify a draw before you make it.
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by published lab tests
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This calculator is for educational and research purposes only and does not constitute medical advice. Doses shown on this page are commonly cited research figures, presented as reference. Compounds discussed may be investigational and not approved for human use. Consult a qualified healthcare provider. Peptigrity is an independent review platform and does not sell, endorse or recommend specific products or vendors.