How to Reconstitute Lyophilized Peptides: A Complete Guide

Introduction

Reconstitution is the process of dissolving a lyophilized (freeze-dried) peptide back into solution using a diluent. For research applications, this is the step between receiving a vial and having a working solution — and it's where the most common handling errors occur.

What you need

• The lyophilized peptide vial at room temperature
• Bacteriostatic water (BAC water) — 0.9% benzyl alcohol
• Sterile syringe and needle
• Alcohol swabs for septum sterilization

Standard reconstitution procedure

1. Equilibrate the vial. Allow lyophilized vial to reach room temperature (15–30 min).
2. Sterilize the septums. Wipe with a fresh alcohol swab; let alcohol fully evaporate.
3. Draw the target volume of BAC water into the syringe.
4. Inject slowly, against the wall. Angle needle so BAC water runs down the inside wall.
5. Dissolve by swirling, never shaking. Gentle circular motion until fully dissolved (60–90 sec).
6. Inspect. Solution should be clear. Some peptides display characteristic normal colors (BPC-157 yellow, GHK-Cu blue, SS-31 pink).
7. Label and store. Note compound name, concentration, reconstitution date. Refrigerate 2–8°C.

Reconstitution reference table

Vial mass	BAC water	Concentration
5 mg	1.0 mL	5 mg/mL
5 mg	2.0 mL	2.5 mg/mL
10 mg	1.0 mL	10 mg/mL
10 mg	2.0 mL	5 mg/mL
100 mg	5.0 mL	20 mg/mL

Common mistakes to avoid

1. Vortexing to speed dissolution (damages peptides — always swirl)
2. Injecting directly onto the lyophilized cake (causes foaming)
3. Reconstituting a cold vial (condensation contaminates the powder)
4. Freezing reconstituted material (aggregates peptides)