How to Reconstitute Peptides

What reconstitution means

Research peptides are supplied as a lyophilised (freeze-dried) powder for stability during storage and transport. Before they can be measured and used in a research setting, the powder must be dissolved into a liquid. This process is called reconstitution. Getting it right protects the integrity of the material; getting it wrong can degrade or contaminate the peptide and waste the vial.

Which liquid to use

The solvent of choice for most research peptides is bacteriostatic water— sterile water containing 0.9% benzyl alcohol. The benzyl alcohol inhibits bacterial growth, which allows a vial to be accessed multiple times over roughly 28 days without spoiling.

• Bacteriostatic water— preferred for multi-use vials. Stable and preserved.
• Sterile / water for injection— no preservative, suitable only for single-use scenarios.
• Avoid tap water— impurities, chlorine and bacteria compromise the material immediately.
• Avoid saline unless specified— electrolytes can degrade certain peptides.

Calculating concentration

Concentration is simply the amount of peptide divided by the volume of water you add:

The amount of peptide is fixed by the vial. The volume of water is your choice, and it sets how concentrated the solution is. Worked example:

Adding more water makes each measured draw larger and easier to read accurately; adding less makes the solution more concentrated. The total amount of peptide never changes.

Step-by-step technique

1. Sanitise. Wipe both vial stoppers with an alcohol swab and let them dry for 30 to 60 seconds.
2. Draw the water. Draw your calculated volume of bacteriostatic water into a sterile syringe.
3. Add slowly. Inject the water slowly down the inside wall of the peptide vial, not directly onto the powder. Direct impact can damage the peptide.
4. Dissolve gently. Swirl the vial gently until the solution is clear. Do not shake— agitation can degrade peptide chains.
5. Store correctly. Refrigerate and protect from light.

Storage

• Lyophilised (before reconstitution):store at -20°C for maximum shelf life.
• Reconstituted:refrigerate at 2 to 8°C and use within approximately 28 to 30 days.
• Avoid repeated freeze-thaw cycles and prolonged light exposure, both of which reduce peptide integrity.

Common mistakes

• Using the wrong liquid (tap water, plain saline).
• Injecting water straight onto the powder.
• Shaking the vial instead of swirling.
• Skipping stopper sanitisation.
• Miscalculating concentration and mismeasuring draws.

Frequently asked questions