THE PROTOCOL KIT

Peptide Reconstitution Calculator

Calculate BAC water volume, syringe draw units, concentration, and doses per vial instantly.

Use this tool as both a peptide reconstitution calculator and a peptide dosing calculator — enter your vial strength, target dose, and BAC water volume to get an exact syringe draw for any research peptide.

Reconstitution Calculator

Dose (mg)
Vial Strength (mg)
Water Volume (mL)

Your Protocol

SELECTED DOSE:0.5 mg
DRAW SYRINGE TO:10 units (0.1 mL)
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Doses per vial
20
Solution concentration
5mg/mL

How to Use This Peptide Calculator

Vial Strength

The total amount of peptide in your vial, listed on the label (e.g. 5 mg, 10 mg). This is the dry, lyophilized powder before any water is added.

Target Dose

The amount of peptide you want to inject per dose, in mg or mcg. Check community protocols for your specific peptide — typical research doses range from 100 mcg to several mg.

BAC Water Volume

How much bacteriostatic water you add to the vial, in mL. This determines the final concentration. 2 mL is a common starting point for a 5 mg vial.

Peptide Calculator Examples

BPC-157

Vial Strength
5 mg
BAC Water
2 mL
Target Dose
250 mcg
Concentration
2.5 mg/mL
Draw
10 units (0.10 mL)
Doses per vial
20

TB-500

Vial Strength
5 mg
BAC Water
2 mL
Target Dose
2 mg
Concentration
2.5 mg/mL
Draw
80 units (0.80 mL)
Doses per vial
2.5

Retatrutide

Vial Strength
10 mg
BAC Water
2 mL
Target Dose
2 mg
Concentration
5 mg/mL
Draw
40 units (0.40 mL)
Doses per vial
5

Ipamorelin

Vial Strength
5 mg
BAC Water
2 mL
Target Dose
300 mcg
Concentration
2.5 mg/mL
Draw
12 units (0.12 mL)
Doses per vial
16

Common Peptide Dosing Reference

PeptideCommon dose rangeTypical vial sizeRecommended concentration
BPC-157200–500 mcg5 mg2.5 mg/mL (2 mL BAC)
TB-5002–5 mg / week5–10 mg2.5–5 mg/mL
Ipamorelin200–300 mcg5 mg2.5 mg/mL
CJC-1295 (no DAC)100–200 mcg2–5 mg1–2.5 mg/mL
Semaglutide0.25–2.4 mg / week5–10 mg2.5–5 mg/mL
Tirzepatide2.5–15 mg / week10–30 mg5–10 mg/mL
Retatrutide1–8 mg / week10 mg5 mg/mL
GHK-Cu1–2 mg50–100 mg10 mg/mL
MOTS-c5–10 mg / week10 mg5 mg/mL

For research purposes only. Dose ranges reflect common research community practice, not clinical recommendations.

The Peptide Reconstitution Formula Explained

  1. 1. Calculate concentration

    Concentration (mg/mL) = Vial Strength (mg) ÷ BAC Water (mL)

  2. 2. Calculate volume

    Volume (mL) = Target Dose (mg) ÷ Concentration (mg/mL)

  3. 3. Convert to syringe units

    Units (U-100) = Volume (mL) × 100

  4. Doses per vial

    Doses per vial = Vial Strength (mg) ÷ Target Dose (mg)

    Tells you how many injections you'll get from a single reconstituted vial before needing to mix a new one.

Bacteriostatic Water for Peptide Reconstitution

Bacteriostatic water (BAC water) is sterile water containing 0.9% benzyl alcohol — a mild preservative that prevents bacterial growth in the vial after it's punctured. It's the standard diluent for reconstituting research peptides.

Why not regular sterile water?

Plain sterile water has no preservative. Once you puncture the vial, any microbes introduced can multiply. BAC water keeps a reconstituted peptide stable in the refrigerator for roughly 28 days.

How much BAC water to use?

More water → lower concentration → larger, easier-to-read draw. Less water → higher concentration → smaller draw, more doses per vial. 2 mL per 5 mg vial is the most common starting point. Use the calculator above to dial in your exact volume.

Where to source bacteriostatic water

We use PSPeptides for BAC water, syringes, and research peptides. Use code BANANAS10 for 10% off.

Shop PSPeptides →

How to Reconstitute Peptides

  1. 1. Gather your supplies

    You'll need your lyophilized peptide vial, bacteriostatic water (BAC Water), a U-100 insulin syringe, and alcohol prep pads. Work on a clean, flat surface in a well-lit area.

  2. 2. Clean the vial stopper

    Wipe the rubber stopper of the peptide vial with an alcohol pad and let it air-dry for a few seconds. This reduces the chance of introducing contaminants when you puncture the seal.

  3. 3. Draw your BAC Water

    Pull the plunger to draw the amount of BAC Water you calculated into the syringe. For most 5 mg vials, 2 mL is a common starting volume. See our peptide dosage chart for common ratios across compounds.

  4. 4. Inject into the vial at an angle

    Insert the needle through the center of the rubber stopper at a slight angle. Inject the BAC Water slowly and gently down the inside wall of the vial. A slow stream prevents excessive foaming, which can damage delicate peptide chains.

  5. 5. Mix gently — do not shake

    Once the water is in, swirl the vial slowly in a circular motion until the powder is fully dissolved. Avoid shaking or vortexing, as vigorous agitation can degrade the peptide structure.

  6. 6. Inspect the solution before use

    The final solution should be clear and free of visible particles or cloudiness. If you notice floaters or persistent cloudiness, discard the vial and start with a new one.

Understanding Your Reconstitution Ratio

Every reconstitution comes down to three numbers: vial strength (the total peptide in the vial), BAC Water volume (how much diluent you add), and the resulting concentration (strength divided by volume). Getting this ratio right is what determines whether your syringe draw is a practical 10–20 units or an impossibly tiny 2 units. A higher concentration means smaller draws per dose and more total doses from the vial, but it also makes precise measurement harder. This is the core math any peptide reconstitution calculator or peptide dosing calculator has to solve.

For example, a 5 mg vial reconstituted with 2 mL of BAC Water yields 2.5 mg/mL. If your target dose is 250 mcg (0.25 mg), you'll draw 10 units. Change that to 1 mL of BAC Water and the same dose becomes just 5 units — harder to eyeball accurately. This is why most researchers start with 2 mL for 5 mg vials and scale from there. Our peptide dosage chart lists common starting ratios for every major compound, and our bacteriostatic water guide walks through sourcing and storage.

Different peptides have different optimal concentrations. BPC-157 and TB-500 are often reconstituted at 2.5 mg/mL, while larger vials like GHK-Cu may call for 10 mg/mL to keep draws manageable. For GLP-1 compounds, see our tirzepatide dosage guide or semaglutide protocol for compound-specific recommendations.

How to Reconstitute Peptides FAQ

Peptide Calculator FAQ

About The Protocol Kit Peptide Calculator

The Protocol Kit Peptide Calculator is a free, no-signup tool built for the research peptide community. It handles the reconstitution math for any lyophilized peptide — BPC-157, TB-500, ipamorelin, semaglutide, tirzepatide, retatrutide, and more — so you can stop second-guessing syringe draws and focus on your protocol.

Free Peptide Reconstitution Guide

Download our complete step-by-step reconstitution guide — free, no email required.

Download the free guide →