How to Reconstitute Peptides: Step-by-Step Guide
Published: January 8, 2026
Category: Beginner Guides
Author: The Peptide Index
AI SUMMARY
What reconstitution means: Reconstitution is the process of adding bacteriostatic water to lyophilized (freeze-dried) peptide powder to create an injectable solution.
What you need: Lyophilized peptide vial, bacteriostatic water, insulin syringes, alcohol swabs, and a clean workspace.
The basic process: Draw bacteriostatic water into a syringe, inject it slowly down the inside wall of the peptide vial, let it dissolve without shaking, then refrigerate.
Standard ratio: Most researchers use 1-2mL of bacteriostatic water per peptide vial, which makes dosing calculations straightforward.
Storage after reconstitution: Reconstituted peptides must be refrigerated (36-46°F / 2-8°C) and typically remain stable for 3-4 weeks.
What Is Reconstitution?
Peptides are sold as lyophilized powder, a freeze-dried form that keeps them stable during shipping and storage. Before use, this powder must be mixed with a sterile liquid to create an injectable solution. This process is called reconstitution.
Think of it like powdered drink mix. The powder is stable on the shelf, but you need to add water before you can use it. The difference is that peptide reconstitution requires sterile technique and specific liquids to maintain the peptide's integrity.
What You Need
Required Supplies
Bacteriostatic Water (BAC Water)
Sterile water containing 0.9% benzyl alcohol as a preservative
The benzyl alcohol prevents bacterial growth after opening
Available in 10mL or 30mL vials
Do not substitute with saline, sterile water for injection, or tap water
Insulin Syringes
1mL (100 unit) insulin syringes work best
29-31 gauge needles are standard
Get syringes with clearly marked units for accurate measuring
Alcohol Swabs
70% isopropyl alcohol prep pads
Used to sterilize vial tops before drawing
Your Peptide Vial
Lyophilized (freeze-dried) powder
Check the labeled amount (typically in mg)
Optional But Helpful
Clean workspace or tray
Sharps container for needle disposal
Calculator for dosing math
Notepad to record reconstitution details
Step-by-Step Reconstitution Process
Step 1: Prepare Your Workspace
Clean your work surface with alcohol or disinfectant. Wash your hands thoroughly. Gather all supplies before starting.
Remove the peptide vial from the refrigerator if stored cold. Let it reach room temperature for a few minutes. Cold vials can cause condensation issues.
Step 2: Determine How Much Bacteriostatic Water to Add
The amount of BAC water you add determines your concentration. There's no single "correct" amount, but common choices are:
For a 5mg peptide vial:
Add 1mL BAC water = 5mg/mL (5000mcg per mL)
Add 2mL BAC water = 2.5mg/mL (2500mcg per mL)
For a 10mg peptide vial:
Add 1mL BAC water = 10mg/mL (10,000mcg per mL)
Add 2mL BAC water = 5mg/mL (5000mcg per mL)
Using 1mL or 2mL makes the math simple. More water means a more diluted solution and larger injection volumes. Less water means a more concentrated solution and smaller injection volumes.
Step 3: Sterilize the Vial Tops
Use an alcohol swab to wipe the rubber stopper on both vials:
The bacteriostatic water vial
The peptide vial
Let them air dry for a few seconds. Don't blow on them or wipe with anything else.
Step 4: Draw Bacteriostatic Water
Remove the cap from a new insulin syringe
Pull the plunger back to your desired amount (e.g., 100 units = 1mL)
Insert the needle through the rubber stopper of the BAC water vial
Push the air into the vial (this makes drawing easier)
Turn the vial upside down with the syringe still inserted
Pull the plunger back slowly to draw your desired amount
Tap out any air bubbles and push them back into the vial
Withdraw the needle
Step 5: Add Water to Peptide Vial
This is the critical step. Do not inject directly onto the powder.
Insert the needle through the rubber stopper of the peptide vial
Angle the needle so it touches the inside wall of the vial
Push the plunger SLOWLY, letting the water trickle down the glass wall
The water should gently flow down and pool at the bottom
Do not spray or squirt the water directly onto the powder
Remove the needle when done
Step 6: Let It Dissolve
Do not shake the vial. Shaking can damage peptide molecules.
Set the vial on a flat surface
Wait 5-10 minutes
The powder should dissolve on its own
If some powder remains, gently roll the vial between your palms
Never shake vigorously
Most peptides dissolve into a clear, colorless solution. Some may have a slight tint. If you see floating particles that won't dissolve, cloudy solution, or unusual color, the peptide may be degraded.
Step 7: Label and Store
Once dissolved:
Write on the vial or a label:
Date of reconstitution
Concentration (e.g., "5mg/mL" or "250mcg per 5 units")
Peptide name if not clearly labeled
Store immediately in the refrigerator (36-46°F / 2-8°C)
Never freeze reconstituted peptides
Calculating Your Dose
Once reconstituted, you need to calculate how many units to draw for your desired dose.
The Formula
Dose (units) = (Desired mcg ÷ Total mcg in vial) × Total units of water added
Example Calculations
Example 1: BPC-157
Vial contains: 5mg (5000mcg)
Water added: 1mL (100 units)
Desired dose: 250mcg
Calculation: (250 ÷ 5000) × 100 = 5 units
Example 2: TB-500
Vial contains: 5mg (5000mcg)
Water added: 2mL (200 units)
Desired dose: 2500mcg (2.5mg)
Calculation: (2500 ÷ 5000) × 200 = 100 units (1mL)
Example 3: Ipamorelin
Vial contains: 5mg (5000mcg)
Water added: 2.5mL (250 units)
Desired dose: 200mcg
Calculation: (200 ÷ 5000) × 250 = 10 units
Quick Reference Chart
For a 5mg vial with 1mL (100 units) of BAC water:
Desired Dose Units to Draw 100mcg 2 units 250mcg 5 units 500mcg 10 units 1000mcg (1mg) 20 units 2500mcg (2.5mg) 50 units
For a 10mg vial with 2mL (200 units) of BAC water:
Desired Dose Units to Draw 100mcg 2 units 250mcg 5 units 500mcg 10 units 1000mcg (1mg) 20 units 2500mcg (2.5mg) 50 units
Storage After Reconstitution
Refrigeration Is Required
Once reconstituted, peptides must be kept cold. The benzyl alcohol in bacteriostatic water prevents bacterial growth, but peptides themselves degrade at room temperature.
Proper storage:
Temperature: 36-46°F (2-8°C)
Location: Main refrigerator compartment, not the door
Protection: Keep away from light
Position: Upright if possible
Shelf Life After Reconstitution
Most reconstituted peptides remain stable for:
3-4 weeks when properly refrigerated
A few hours at room temperature
Do not freeze - freezing damages the solution
Some peptides are more fragile than others. When in doubt, use within 3 weeks of reconstitution.
Signs of Degradation
Discard the peptide if you notice:
Cloudiness or haziness (should be clear)
Floating particles
Color change
Unusual smell
Solution that was left unrefrigerated for extended periods
Common Mistakes to Avoid
1. Spraying Water Directly on Powder
This can damage peptide molecules. Always let the water trickle down the vial wall.
2. Shaking the Vial
Vigorous shaking creates foam and can denature (damage) the peptide. Gentle rolling is acceptable if needed.
3. Using the Wrong Liquid
Only use bacteriostatic water for peptides you'll use over multiple days. Sterile water without preservative allows bacterial growth after opening. Saline can affect stability of some peptides.
4. Forgetting to Refrigerate
Reconstituted peptides left at room temperature degrade rapidly. Refrigerate immediately after mixing.
5. Reusing Needles
Each time you draw from the vial, use a new sterile needle. Reusing needles introduces bacteria and dulls the point.
6. Adding Too Little Water
While technically workable, very concentrated solutions are hard to dose accurately. Tiny volumes like 2-3 units are difficult to measure precisely on a syringe.
7. Not Labeling
After a few days, you may forget the concentration or reconstitution date. Always label your vials.
Frequently Asked Questions
Can I use sterile water instead of bacteriostatic water?
For single-use vials that will be used entirely in one injection, sterile water for injection works. For multi-use vials (most peptides), bacteriostatic water is necessary because the benzyl alcohol prevents bacterial contamination between uses.
How do I know if my peptide dissolved properly?
Properly reconstituted peptides form a clear, colorless solution with no visible particles. Some peptides may have a very slight color, but cloudiness or floating material indicates a problem.
Can I reconstitute multiple vials at once?
Yes, but use a fresh needle for each vial to prevent cross-contamination. Don't combine powder from multiple vials into one.
What if I add too much or too little water?
Adding more water just means you have a more diluted solution and need to inject more volume for your dose. Adding less means a more concentrated solution and smaller volumes. Neither ruins the peptide, just adjust your dosing calculations.
Can I travel with reconstituted peptides?
Reconstituted peptides need refrigeration. For short trips (a few hours), an insulated bag with ice packs may work. For longer travel, this becomes challenging. Some researchers reconstitute upon arrival rather than transporting liquid.
Why is my peptide not dissolving?
Give it time. Some peptides take 10-15 minutes to fully dissolve. Gently roll the vial if needed. If it still won't dissolve after 30 minutes of gentle rolling, the peptide may have degraded during shipping or storage.
How long can unreconstituted peptides be stored?
Lyophilized (powder) peptides are much more stable:
Room temperature: 1-3 months (varies by peptide)
Refrigerated: 6-12 months
Frozen: 1-2 years or longer
Check your specific peptide's storage recommendations.
Key Takeaways
Reconstitution = adding bacteriostatic water to peptide powder to create an injectable solution
Use bacteriostatic water, not sterile water or saline for multi-use vials
Add water slowly down the vial wall, never spray directly onto the powder
Do not shake - let the peptide dissolve naturally or roll gently
Refrigerate immediately after reconstitution
Use within 3-4 weeks of reconstitution
Label your vials with date, concentration, and peptide name
Simple math determines your dose: (desired mcg ÷ total mcg) × total units
Related Guides
Disclaimer: This content is for educational and research purposes only. Peptides discussed are not FDA-approved for human use. Nothing in this article constitutes medical advice. Consult qualified professionals for guidance.
Last updated: January 8, 2026
