What is Peptide Reconstitution?
Reconstitution is the process of dissolving a lyophilised (freeze-dried) peptide powder into a liquid solution, making it ready for use. Most research peptides are supplied as a dry powder in a sealed vial, and must be reconstituted before they can be used. This guide walks you through the process step by step.
What You'll Need
- Your peptide vial (lyophilised powder)
- Bacteriostatic water (BAC water) — recommended for multi-use vials
- A sterile insulin syringe (1 mL, U-100)
- Alcohol swabs
- A clean, flat surface
Why bacteriostatic water? BAC water contains 0.9% benzyl alcohol, which prevents bacterial growth and extends the shelf life of your reconstituted peptide to 4–6 weeks when refrigerated. Plain sterile water should only be used if the entire vial will be used within 24–48 hours.
Step-by-Step Reconstitution Process
Step 1: Gather your supplies
Ensure everything is clean and sterile. Wash your hands thoroughly. Lay out your peptide vial, BAC water vial, insulin syringe, and alcohol swabs on a clean surface.
Step 2: Clean the vial tops
Wipe the rubber stopper on both the peptide vial and the BAC water vial with a fresh alcohol swab. Allow them to air dry for 10–15 seconds before proceeding.
Step 3: Draw the bacteriostatic water
Using your insulin syringe, draw the desired volume of BAC water. The amount you add will determine the concentration of your solution. A common approach for a 5 mg vial is to add 2 mL of BAC water, giving a concentration of 2,500 mcg/mL.
Use our Peptide Dosage Calculator to determine the right volume for your desired concentration.
Step 4: Inject the water slowly into the peptide vial
Insert the syringe needle through the rubber stopper of the peptide vial at an angle, so the water runs down the side of the vial rather than directly onto the powder. This is important — forcing water directly onto the powder can damage the peptide structure.
Inject the BAC water slowly and gently. Do not squirt it in forcefully.
Step 5: Do not shake — swirl gently
Once the water is added, do not shake the vial. Shaking can cause the peptide to foam and degrade. Instead, gently swirl or roll the vial between your palms until the powder is fully dissolved. This may take 30 seconds to a few minutes.
The resulting solution should be clear and colourless. If it appears cloudy or has visible particles, do not use it.
Step 6: Label your vial
Once reconstituted, label the vial with:
- Peptide name
- Date of reconstitution
- Concentration (e.g., 2,500 mcg/mL)
- Volume of BAC water added
Step 7: Store correctly
Place the reconstituted vial in the refrigerator immediately (2–8°C). Do not freeze a reconstituted peptide. See our Peptide Storage Guide for full storage recommendations.
Calculating Your Dose After Reconstitution
Once reconstituted, you'll need to know how many units to draw in your syringe for each dose. Use this formula:
Volume (mL) = Desired dose (mcg) ÷ Concentration (mcg/mL)
For example, if your concentration is 2,500 mcg/mL and you want a 250 mcg dose:
250 ÷ 2,500 = 0.1 mL = 10 units on a U-100 insulin syringe
Or simply use our Peptide Dosage Calculator to do the maths for you.
Common Mistakes to Avoid
- Shaking the vial — always swirl gently instead.
- Injecting water directly onto the powder — always aim for the side of the vial.
- Using plain sterile water for multi-use vials — use BAC water to extend shelf life.
- Forgetting to label the vial — always record the date and concentration.
- Freezing reconstituted peptides — refrigerate only.
Summary
Reconstituting a peptide is a straightforward process when done carefully. The key steps are: clean your vials, add BAC water slowly down the side of the vial, swirl gently until dissolved, label the vial, and refrigerate immediately. With the right technique, your reconstituted peptide will remain stable and effective for weeks.