Peptide reconstitution is the process of adding a solvent (typically bacteriostatic water) to a lyophilized (freeze-dried) peptide powder to create an injectable solution. Proper reconstitution is essential for accurate dosing, maintaining peptide stability, and ensuring safe administration.
Why Reconstitution Matters
Peptides are shipped as freeze-dried powders because the lyophilized form is far more stable than liquid solutions. When you're ready to use a peptide, you must reconstitute it carefully. Incorrect reconstitution can destroy the peptide, create inaccurate concentrations, or introduce contamination.
Reconstitution Supplies
| Supply | Purpose | Notes |
|---|---|---|
| Bacteriostatic water (BAC water) | Solvent for reconstitution | Contains 0.9% benzyl alcohol as preservative |
| Insulin syringes (1mL/100 unit) | Measuring and injecting | 29-31 gauge for subcutaneous use |
| Alcohol swabs | Sterilization | Clean vial tops before each use |
| Peptide vial | Contains lyophilized peptide | Store reconstituted vials in refrigerator |
Step-by-Step Reconstitution Guide
Step 1: Gather and Prepare
Wash hands thoroughly. Lay out your bacteriostatic water, peptide vial, insulin syringe, and alcohol swabs on a clean surface. Allow the peptide vial to reach room temperature if refrigerated.
Step 2: Clean Vial Tops
Wipe the tops of both the bacteriostatic water vial and the peptide vial with alcohol swabs. Allow to air dry for 10-15 seconds.
Step 3: Draw Bacteriostatic Water
Using an insulin syringe, draw the desired amount of bacteriostatic water. Common amounts are 1mL or 2mL depending on the peptide amount and desired concentration.
Step 4: Add Water to Peptide Vial
Insert the needle into the peptide vial at an angle, aiming the stream of water against the glass wall — not directly onto the powder. Slowly push the plunger to release water gently down the side of the vial.
Step 5: Allow to Dissolve
Gently swirl the vial in a circular motion. Never shake vigorously, as this can damage the peptide structure through shearing forces. Most peptides dissolve within 1-5 minutes. If undissolved particles remain, let the vial sit in the refrigerator for 30 minutes.
Reconstitution Calculator
Use this reference table to determine how many units to draw for your desired dose based on peptide vial size and water added:
5mg Peptide Vial
| BAC Water Added | Concentration | 100mcg | 250mcg | 500mcg | 1000mcg |
|---|---|---|---|---|---|
| 1.0mL | 5000mcg/mL | 2 units | 5 units | 10 units | 20 units |
| 2.0mL | 2500mcg/mL | 4 units | 10 units | 20 units | 40 units |
| 2.5mL | 2000mcg/mL | 5 units | 12.5 units | 25 units | 50 units |
10mg Peptide Vial
| BAC Water Added | Concentration | 100mcg | 250mcg | 500mcg | 1000mcg |
|---|---|---|---|---|---|
| 1.0mL | 10000mcg/mL | 1 unit | 2.5 units | 5 units | 10 units |
| 2.0mL | 5000mcg/mL | 2 units | 5 units | 10 units | 20 units |
| 3.0mL | 3333mcg/mL | 3 units | 7.5 units | 15 units | 30 units |
The Universal Formula
To calculate any dose: Units to draw = (Desired dose ÷ Concentration) × 100
Where concentration = Peptide amount in vial ÷ Water added (in mL)
Storage After Reconstitution
| Storage Method | Shelf Life | Notes |
|---|---|---|
| Refrigerator (2-8°C / 36-46°F) | 21-28 days | Standard recommendation with BAC water |
| Room temperature | Not recommended | Significantly reduces stability |
| Freezer (reconstituted) | Not recommended | Freeze-thaw cycles damage peptides |
| Lyophilized (unreconstituted) | 12-24 months (refrigerated) | Most stable form |
Common Reconstitution Mistakes
- Spraying water directly onto powder — This can damage the peptide. Always aim at the glass wall.
- Shaking the vial — Vigorous shaking denatures proteins. Gently swirl instead.
- Using sterile water instead of BAC water — Sterile water lacks preservative, limiting shelf life to 24 hours and increasing contamination risk.
- Not cleaning vial tops — Always swab with alcohol before each use to prevent contamination.
- Drawing air bubbles — Flick the syringe to move bubbles to the top and push them out before injecting.
Frequently Asked Questions
How much bacteriostatic water should I add to a peptide vial?
The amount of bacteriostatic water depends on your desired concentration. For a 5mg vial, adding 2mL creates a concentration of 2500mcg/mL, which makes dosing straightforward. Adding less water creates a more concentrated solution (smaller injection volumes), while more water makes measuring easier but requires larger injection volumes.
How long does a reconstituted peptide last?
When reconstituted with bacteriostatic water and stored in the refrigerator (2-8°C), most peptides remain stable for 21-28 days. If reconstituted with sterile water (no preservative), use within 24 hours. Always check for cloudiness, particles, or color changes before use — if present, discard the vial.
Can I use regular water to reconstitute peptides?
No. Only use bacteriostatic water or sterile water for injection. Regular tap or bottled water contains contaminants, minerals, and microorganisms that can degrade the peptide and cause infection. Bacteriostatic water is preferred because its benzyl alcohol preservative inhibits bacterial growth, extending shelf life to 28 days.
Conclusion
Proper peptide reconstitution is a fundamental skill for anyone working with research peptides. By following sterile technique, using the correct solvent, and calculating your concentration accurately, you ensure both accurate dosing and maximum peptide stability throughout the vial's usable life.