How to Reconstitute Peptides: A Complete Guide
Step-by-step instructions for properly mixing lyophilized peptides with bacteriostatic water for research use.
The Essential Skill for Peptide Research
If you're working with research peptides, understanding proper reconstitution is essential. Lyophilized (freeze-dried) peptides must be carefully mixed with appropriate sterile water before use. Done correctly, this process is straightforward. Done incorrectly, you risk degrading valuable research compounds.
What You'll Need
Before beginning, gather these supplies:
- Lyophilized peptide (in sealed vial)
- Bacteriostatic water (BAC water)
- Sterile syringe with needle
- Alcohol swabs
- Clean workspace
Important: Only use bacteriostatic water for peptides that will be stored after reconstitution. It contains 0.9% benzyl alcohol that prevents bacterial growth during storage.
Step-by-Step Reconstitution
#### Step 1: Prepare Your Workspace
Clean your workspace with alcohol. Ensure good lighting so you can see what you're doing. Remove the plastic caps from both the peptide vial and BAC water.
#### Step 2: Clean the Vial Tops
Wipe the rubber stopper of both vials with alcohol swabs. Allow them to dry completely.
#### Step 3: Draw Bacteriostatic Water
Calculate how much BAC water you need (see dosing calculations below). Draw this amount into a sterile syringe.
#### Step 4: Add Water to Peptide Vial
Insert the needle through the rubber stopper of the peptide vial. Critical: Aim the needle at the inside wall of the vial, not directly at the powder.
Release the water slowly, allowing it to run down the side of the vial. Never spray directly onto the powder—this can damage peptide structure.
#### Step 5: Allow the Peptide to Dissolve
Do not shake the vial. Instead:
- Gently swirl if needed
- Or simply let it sit for a few minutes
- The peptide should dissolve completely
A clear solution indicates successful reconstitution. Cloudiness or particles may indicate problems.
Dosing Calculations Made Simple
The Easy Formula:
If you add 1mL of BAC water to a 5mg vial:
- 5mg ÷ 1mL = 5mg/mL concentration
- Each 0.1mL (10 units on insulin syringe) = 0.5mg (500mcg)
Common Example:
- 5mg peptide vial
- Add 2mL BAC water
- Concentration = 2.5mg/mL
- Each 0.1mL = 250mcg
Storage After Reconstitution
Once reconstituted:
- Store in refrigerator (2-8°C)
- Protect from light
- Use within 30 days for most peptides
- Some peptides degrade faster—check specific guidelines
Common Mistakes to Avoid
- Spraying water directly on powder - Damages peptide structure
- Shaking the vial - Can denature peptides
- Using regular sterile water - No preservative for multi-use
- Storing at room temperature - Accelerates degradation
- Using cloudy solutions - May indicate contamination or degradation
Quality Indicators
A properly reconstituted peptide should be:
- Completely clear
- Free of particles or cloudiness
- Colorless (unless the specific peptide has color)
If the solution is cloudy, has particles, or won't dissolve completely, the peptide may be compromised.
The Bottom Line
Reconstitution is a fundamental skill for peptide research. Following these steps ensures you maintain the integrity of your research compounds and get consistent, reliable results.
Take your time, work cleanly, and never cut corners with sterile technique.
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