How to reconstitute any peptide correctly -- BAC water, insulin syringe units, and how to avoid the most common dosing mistakes. Includes a free calculator.
Why Reconstitution Accuracy Matters Peptides arrive as lyophilized (freeze-dried) powder. Before injection, they must be reconstituted -- dissolved into bacteriostatic water to create a liquid solution. Getting this step wrong does not just waste an expensive vial. Errors in reconstitution translate directly to errors in dosing: you might be injecting half your intended dose, or double it, with no way to know. This guide covers the complete reconstitution process with exact calculations. Use the free MyProtocolStack reconstitution calculator to confirm your numbers before every new vial.
Critical note on BAC water: Bacteriostatic water contains 0.9% benzyl alcohol, which prevents bacterial growth in the reconstituted vial for up to 28-60 days when refrigerated. Regular sterile water has no preservative -- reconstituted peptides in sterile water should be used within 24 hours.
Formula: Concentration = (Vial size in mg multiplied by 1000) divided by BAC water added (mL)
Example 1: 5mg BPC-157 plus 2mL BAC water = Concentration of (5 x 1000) divided by 2 = 2,500 mcg/mL
Example 2: 2mg Ipamorelin plus 2mL BAC water = Concentration of (2 x 1000) divided by 2 = 1,000 mcg/mL
To find syringe units for your dose:
Units to draw = (Desired dose in mcg divided by Concentration mcg/mL) multiplied by 100
Example: 250mcg BPC-157 from a 2,500 mcg/mL solution = (250 divided by 2,500) multiplied by 100 = 10 units
Step 1: Wash hands thoroughly. Let the peptide vial come to room temperature if refrigerated.
Step 2: Wipe the rubber stopper of both the peptide vial and the BAC water vial with an alcohol swab. Allow to dry for 30 seconds before inserting any needle.
Step 3: Using your drawing syringe, draw the calculated volume of BAC water. Do not use the same syringe you will use for injections -- drawing from vials dulls needles.
Step 4: Insert the drawing needle into the peptide vial at an angle. Slowly release the BAC water down the side of the vial -- do not squirt it directly onto the powder. Allow it to flow down the glass.
Step 5: Gently swirl or rotate the vial to mix. Never shake peptides -- shaking creates air bubbles and can damage the peptide structure.
Step 6: The reconstituted solution should be clear, colorless, and free of particles. If it is cloudy, has visible particles, or has a color, do not use it.
Step 7: Label the vial with the date reconstituted. Refrigerate at 2-8 degrees C. Use within 28-60 days for BAC water reconstitution.
Mistake 1: Shaking the vial -- Mechanical agitation can unfold peptide chains, potentially reducing potency. Always swirl gently.
Mistake 2: Not allowing alcohol to dry -- Alcohol residue from swabbing can destroy peptides. Always wait for the swabbed surface to dry before inserting a needle.
Mistake 3: Drawing with the injection needle -- Always use a separate, larger needle to draw from the vial. This preserves the sharpness of the injection needle.
Mistake 4: Room temperature storage -- Reconstituted peptides stored at room temperature degrade rapidly. Always refrigerate.
Mistake 5: No BAC water label date -- Write the reconstitution date on every vial. Most peptides are stable 28-60 days refrigerated -- after that, discard and reconstitute fresh.
MyProtocolStack includes a free reconstitution calculator that does this math automatically. Enter your vial size (mg), BAC water volume (mL), and target dose (mcg) -- the calculator instantly returns the exact number of syringe units to draw. No math, no errors.
Visit myprotocolstack.com/calculators -- no account required.
The information in this article is for educational purposes only. Always consult a licensed healthcare provider before starting any peptide protocol.
Written by Ryan -- Founder, MyProtocolStack. Last Updated: April 2026.
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