Research tool

Reconstitution Calculator

Work out the concentration after mixing and the units to draw for any dose. Reference figures for laboratory handling only.

Your vial

mg
mL

The syringe scales the draw-reference table below.

Result

Each insulin unit delivers
50 mcg per unit (U-100)
Concentration
5,000 mcg/mL (5 mg/mL)

Draw reference

Units and volume to draw for a range of common doses at this concentration. Doses past your syringe’s capacity are marked —.

DoseDraw (units)Volume

How much water to add

Standard reconstitution volumes by vial size. Tap a row to load it into the calculator above.

VialWaterConcentration1 unitBest for
2 mg1 mL2,000 mcg/mL20 mcgSemax, Selank, DSIP & small-dose peptides
5 mg1 mL5,000 mcg/mL50 mcgHigher-dose protocols
5 mg2 mL2,500 mcg/mL25 mcgEasier measurement for smaller doses
10 mg2 mL5,000 mcg/mL50 mcgBPC-157, TB-500, CJC-1295 — standard
15 mg3 mL5,000 mcg/mL50 mcgThymosin Alpha-1, Epithalon, larger vials
20 mg2 mL10,000 mcg/mL100 mcgRetatrutide — 1 unit = 0.1 mg
30 mg3 mL10,000 mcg/mL100 mcgRetatrutide large vial
50 mg5 mL10,000 mcg/mL100 mcgHigh-volume research vials

Mixing, step by step

  1. Wipe the bacteriostatic-water vial septum with an alcohol swab; let it dry ~10 seconds.
  2. Draw 2 mL of bacteriostatic water into a sterile syringe.
  3. Wipe the peptide vial septum with a fresh swab and let it dry.
  4. Insert the needle at a 45° angle and inject the water slowly down the inside wall — don’t aim the stream at the powder.
  5. Gently swirl or roll the vial between your palms until fully dissolved. Don’t shake or vortex.
  6. The solution should be clear and colourless. If it’s cloudy or has particles, don’t use it.
  7. Label the vial with today’s date and the concentration: 5,000 mcg/mL.
  8. Refrigerate at 2–8°C (don’t freeze). Use within 4–6 weeks.

The formula

Concentration (mcg/mL)Vial (mg) × 1,000 ÷ Water (mL)
mL to drawDose (mcg) ÷ Concentration (mcg/mL)
Units (U-100)mL to draw × 100

Each insulin unit on a U-100 syringe is 0.01 mL, so units = mL × 100. A 0.5 mL (U-50) or 0.3 mL (U-30) barrel just caps the maximum draw at 50 or 30 units.

Frequently asked questions

What is bacteriostatic water and why is it required?
Bacteriostatic water (BAC water) is sterile water containing 0.9% benzyl alcohol. The benzyl alcohol acts as a preservative, inhibiting bacterial growth in the vial after it’s opened — important for multi-use vials. Plain sterile water has no preservative and is only suitable for single-dose use.
How much BAC water should I add?
The amount of water sets the concentration. Adding 1 mL to a 5 mg vial gives 5,000 mcg/mL; 2 mL gives 2,500 mcg/mL. More water = lower concentration = more units per dose = easier to measure small amounts. For doses under ~200 mcg, 2 mL is generally easier.
What is a U-100 insulin syringe?
U-100 refers to the calibration (100 units per mL). On a U-100 syringe each unit mark = 0.01 mL. They come in three barrel sizes: 0.3 mL (30 units), 0.5 mL (50 units) and 1 mL (100 units).
How long does a reconstituted peptide remain stable?
Stored at 2–8°C with bacteriostatic water, most peptides remain stable for 4–6 weeks. Sealed lyophilised vials can be kept frozen (−20°C) for 12–24 months. Once reconstituted, never refreeze, and always label the vial with the reconstitution date.

Reconstitution Calculator

Welcome to the Pepnerd Reconstitution Calculator, your essential tool for accurately preparing your research peptides. Getting the dosage right is paramount in peptide research, and incorrect reconstitution is one of the most common pitfalls for beginners. This calculator simplifies the complex maths involved, ensuring you can confidently and precisely measure your doses every time.

Understanding the correct dilution ratio is not just about accuracy; it's about the integrity of your research. A miscalculated dose can lead to unreliable results, wasted product, and potentially compromise your entire study. Our calculator is designed to eliminate guesswork, providing clear, actionable instructions so you can focus on your research with peace of mind. For a comprehensive overview, refer to our full reconstitution guide.

How to Use the Calculator

Our Reconstitution Calculator is straightforward to use, requiring just three key pieces of information to provide you with an accurate dosage measurement. You will need to input the following:

  • Vial Size (mg): The total amount of peptide contained in your vial, typically measured in milligrams.
  • Bacteriostatic Water Volume (mL): The exact volume of bacteriostatic water you plan to add to your peptide vial, measured in millilitres.
  • Desired Dose (mcg): The specific amount of peptide you wish to administer per dose, measured in micrograms.

Once these values are entered, the calculator will output the number of units on a U-100 insulin syringe required to achieve your desired dose. This ensures precise measurement, especially crucial for potent peptides.

Worked Examples

To illustrate how the calculator works, let's walk through a couple of common scenarios:

Example 1

Imagine you have a 5mg vial of peptide, and you add 2mL of bacteriostatic water. If your desired dose is 250mcg, the calculator will show that you need to draw up to the 10 units mark on a U-100 insulin syringe.

Example 2

Consider a 10mg vial of peptide, reconstituted with 2mL of bacteriostatic water. If you require a 500mcg dose, the calculator will again indicate that you need to draw up to the 10 units mark on a U-100 insulin syringe.

The Reconstitution Formula

For those who prefer to understand the underlying maths, the formula used by our calculator is as follows:

Units = (Desired dose mcg ÷ Total mcg in vial) × mL of water added × 100

This formula accounts for the concentration of your reconstituted peptide and translates it into measurable units on a standard U-100 insulin syringe. For more detailed information on peptide terminology, visit our Peptide Glossary.

About Bacteriostatic Water

Bacteriostatic water is crucial for proper peptide reconstitution, as it helps to preserve the peptide and prevent bacterial growth, extending its shelf life. Always use high-quality bacteriostatic water for your research. Learn more about its importance and the full reconstitution process in our comprehensive Reconstitution Guide.

Further Resources

Ensuring accurate dosing and safe handling practices are key to successful peptide research. Explore our resources for more information: