Guide
How to reconstitute peptides
A step-by-step guide to safely dissolving lyophilized (freeze-dried) peptide vials with bacteriostatic water — from supplies to storage.
Educational research tools — not medical advice.
What you need
- Lyophilized peptide vial — freeze-dried powder
- Bacteriostatic water (BAC water) — not sterile water — BAC water has a preservative for multi-dose use
- Sterile syringe — 1mL U-100 insulin syringe is standard
- Alcohol swabs — to sterilize vial stoppers
- Refrigerator — for storage after reconstitution
Step-by-step reconstitution
- 01
Gather supplies and clean your workspace
Wash hands thoroughly before handling any vials or syringes. Work on a clean, flat surface. You need: your peptide vial (lyophilized), bacteriostatic water (BAC water), a sterile syringe (1mL insulin syringe is common), and alcohol swabs.
- 02
Sterilize the vial stoppers
Wipe the rubber stopper of the peptide vial and the BAC water vial with a fresh alcohol swab. Let both dry for at least 30 seconds before inserting any needle.
- 03
Draw the correct volume of BAC water
Insert the syringe needle into the BAC water vial and draw the volume you've calculated. Use the peptide calculator to find the exact volume — the amount you add determines the concentration of the final solution.
- 04
Add BAC water to the peptide vial — slowly
Insert the needle into the peptide vial at an angle. Aim the stream of water at the inside glass wall, not directly at the powder. Inject slowly. Rushing this step can degrade the peptide.
- 05
Let it dissolve — do not shake
Leave the vial to dissolve at room temperature. Most peptides dissolve within a few minutes. Gently roll the vial if needed. Never shake — this can break peptide bonds and reduce potency.
- 06
Label and store in the refrigerator
Label the vial with the date reconstituted and the concentration (e.g., "2,500 mcg/mL — reconstituted 2026-06-06"). Store at 2–8°C away from light. Most reconstituted peptides are considered stable for 4–8 weeks refrigerated.
Not sure how much BAC water to add?
Use the peptide calculator to find the exact volume for your vial size and desired dose.
Open calculatorStorage after reconstitution
Temperature
2–8°C (refrigerator). Do not freeze reconstituted peptides.
Light
Store away from direct light. Wrapping the vial in foil is a common practice.
Duration
Reconstituted peptides with BAC water are generally considered stable for 4–8 weeks refrigerated, depending on the specific peptide. Consult your provider or peptide documentation for peptide-specific data.
Labeling
Always label with the reconstitution date and concentration so you know when it was prepared.
Common mistakes to avoid
Shaking the vial
Shaking creates bubbles and mechanical stress that can denature the peptide. Gently swirl or roll instead.
Injecting BAC water directly onto the powder
Aim the stream at the inside glass wall so it runs down to the powder gently. Direct injection can damage fragile peptide structures.
Using sterile water instead of BAC water
Sterile water has no bacteriostatic agent, meaning it's only suitable for single-use applications. BAC water is preferred for multi-dose vials.
Leaving reconstituted peptide at room temperature
Reconstituted peptides degrade quickly at room temperature. Refrigerate immediately after reconstitution.
Not verifying the concentration
Incorrect concentration math leads to dosing errors. Always verify with a calculator before drawing doses.