Lyophilized (freeze-dried) peptides arrive as a stable powder in a sealed vial. Before they can be used in laboratory research, they must be reconstituted with an appropriate solvent — most commonly bacteriostatic water. This guide covers the complete process from unboxing to storage.
What You Will Need
- Lyophilized peptide vial
- Bacteriostatic water (0.9% benzyl alcohol)
- U-100 insulin syringe (1mL, 31G recommended)
- Alcohol swabs (70% isopropyl)
- A clean, flat work surface
Step 1: Prepare Your Workspace
Clean your work surface with 70% isopropyl alcohol. Wash your hands thoroughly. Gather all materials before beginning. The peptide vial, bacteriostatic water, and syringe should all be at room temperature before starting.
Step 2: Calculate Your BAC Water Volume
The volume of bacteriostatic water you add determines your final concentration (mg/mL). Use our reconstitution calculator to compute the exact concentration for your vial size and water volume.
Use the reconstitution calculator
Step 3: Wipe the Vial Stoppers
Wipe both the peptide vial rubber stopper and the bacteriostatic water vial stopper with an alcohol swab. Allow 30 seconds for the alcohol to evaporate before inserting any needles.
Step 4: Draw the Bacteriostatic Water
Remove the syringe cap. Pierce the bacteriostatic water vial stopper with the needle. Invert the vial and draw your calculated volume of water. Remove the needle carefully.
Step 5: Inject Water Into the Peptide Vial
This is the critical step. Pierce the peptide vial stopper and slowly inject the water down the INSIDE WALL of the vial — never spray directly onto the powder. Direct impact can denature the peptide chains. Let the water gently run down the glass and pool at the bottom.
Step 6: Allow Dissolution
Do not shake the vial. Let the solution dissolve naturally over 1–3 minutes. Gentle swirling is acceptable if needed, but never shake vigorously. The solution should become clear. If particulates remain after 5 minutes, the peptide may have degraded during shipping — contact [email protected].
Step 7: Storage Guidelines
Once reconstituted, store the peptide solution at 2–8°C (refrigerated). Most reconstituted peptides remain stable for 2–4 weeks under refrigeration. For extended storage beyond 4 weeks, consider aliquoting into separate vials and freezing at -20°C.
Calculate Your Concentration
The concentration of your reconstituted peptide depends entirely on two variables: the amount of peptide in your vial (mg) and the volume of bacteriostatic water you add (mL). Dividing mg by mL gives you mg/mL. Use the reconstitution calculator on our site to compute this for your specific vial.
Frequently Asked Questions
Q: Can I use sterile water instead of bacteriostatic water?
A: Bacteriostatic water is strongly recommended. The 0.9% benzyl alcohol prevents bacterial growth. Sterile water lacks a preservative and should only be used if BAC water is unavailable — use within 24 hours.
Q: How long do reconstituted peptides last?
A: 2–4 weeks refrigerated at 2–8°C. For longer storage, aliquot and freeze at -20°C for up to 6 months.