Lyophilised peptides arrive as a dry cake and need reconstituting before use in research. A clean, repeatable technique protects both the material and your results.
Peptides are shipped lyophilised — freeze-dried into a dry powder or cake — because they are far more stable that way than in solution. Before they can be used in a research setting they have to be reconstituted: dissolved back into a liquid. Done carelessly, reconstitution introduces contamination, denatures the peptide, or gives you a solution of unknown concentration. Done properly, it's straightforward.
What you'll need
- The lyophilised peptide vial, brought to room temperature
- A suitable solvent — most commonly bacteriostatic or sterile water for laboratory work
- A sterile syringe and needle
- An alcohol wipe for the vial stoppers
The technique
Let the vial reach room temperature before opening — adding liquid to cold glass straight from storage encourages condensation. Wipe both stoppers with an alcohol swab. Draw your chosen volume of solvent into the syringe.
Add the solvent slowly, aiming the stream against the inside wall of the vial rather than directly onto the peptide cake. A gentle stream down the glass is far kinder than blasting the powder. Peptides are delicate; foaming and aggressive force can damage them.
Do not shake. Once the solvent is in, swirl the vial gently or let it sit until the cake dissolves on its own. A properly dissolved solution is clear and free of particulates. Cloudiness or floating material is a flag worth investigating before proceeding.
Calculating concentration
Concentration is simply the mass of peptide divided by the volume of solvent you added. For example, 5 mg of peptide reconstituted in 2 mL of water gives 2.5 mg/mL. Deciding the reconstitution volume in advance — and recording it — is what makes your measurements reproducible.
Storage after reconstitution
A reconstituted peptide is much less stable than the dry form. As a general handling principle, keep solutions refrigerated and protected from light, and minimise freeze-thaw cycles. The lyophilised vial itself is best kept cold and dry until the moment you need it.
Slow solvent, no shaking, room-temperature glass. Three habits that prevent most reconstitution problems.
For research use only. This guide covers laboratory handling and does not describe or endorse human or veterinary use.
Written and reviewed to our editorial standards. Explore the research peptide catalog or read more in Research Notes.
For research use only · Not for human or veterinary use
