How to Reconstitute Peptides

Most research peptides ship as a freeze-dried powder. You add bacteriostatic water before you can draw a dose. That process is called reconstitution.

What you need

• The sealed peptide vial
• Bacteriostatic water (BAC water), usually 1 to 3 mL per vial depending on the protocol
• A drawing syringe with a longer needle (often 21G or 23G)
• An insulin syringe (U-100) for dosing
• Alcohol prep pads
• A clean, flat surface

The procedure

1. Wash your hands. Wipe both rubber stoppers (peptide vial and BAC water vial) with a fresh alcohol pad.
2. Draw your chosen volume of BAC water into the drawing syringe.
3. Insert the needle into the peptide vial at an angle so the water runs down the inside wall instead of splashing onto the powder.
4. Let the powder dissolve on its own. If it's slow, swirl the vial gently. Don't shake it.
5. The vial is now reconstituted. Store it in the refrigerator between 2 and 8 °C.

The amount of water you add determines your concentration, which determines how many units you draw on the insulin syringe. Match the protocol's recommended water volume, or run the new number through the reconstitution calculator.

Common mistakes

• Wrong water volume. Adding 3 mL when the protocol expects 2 mL throws off every future dose by 33%.
• Spraying water onto the powder. Some peptides are sensitive to mechanical stress. Run the water down the wall.
• Shaking the vial. Same reason. Gentle swirl only.
• Skipping the alcohol wipe. Contamination risk is small but real, especially with multi-use vials.
• Reusing needles. They go dull fast and increase tissue damage on injection.

After reconstitution

A reconstituted vial is good for 28 days in most cases, since bacteriostatic water contains 0.9% benzyl alcohol that suppresses bacterial growth. Track the date on the vial. Throw it out at 28 days even if there's product left.

For how to read the syringe markings once your dose is calculated, see Understanding Syringe Units.