Reconstitution & Storage

Reconstitution & Storage of Research Peptides

Research peptides are typically supplied as a lyophilised (freeze-dried) powder that must be reconstituted — dissolved into a liquid — before use in laboratory work. Correct reconstitution and storage help preserve a peptide’s structural integrity, so this guide covers general laboratory practice for handling, dissolving and storing research peptides, along with two calculators to support your research measurements. All guidance below is provided for laboratory research purposes only.

Storing Lyophilised Peptides

In their freeze-dried state, peptides are relatively stable and are protected from light during transport. Even so, they should be moved into appropriate storage promptly on arrival. As a general guide, lyophilised peptides kept frozen at around −20°C remain stable for extended periods, while short-term storage in a refrigerator (2–8°C) is suitable for material intended for near-term use. Keep vials sealed, dry and away from direct light.

Storing Reconstituted Peptides

Once a peptide is dissolved, its stability window shortens considerably. Reconstituted solutions are generally stored refrigerated at 2–8°C and used within a matter of weeks. Repeated freezing and thawing should be avoided, as each cycle can degrade the peptide; where longer storage of a solution is required, dividing it into single-use aliquots before freezing helps limit freeze–thaw exposure.

How to Reconstitute a Peptide

The following reflects common laboratory practice:

1. Bring to room temperature. Allow the peptide vial and your solvent (commonly bacteriostatic water) to reach room temperature before mixing. Combining cold liquids can cause cloudiness.
2. Equalise the vial pressure. Freeze-drying can leave a vial under slight vacuum or positive pressure. Introducing a needle part-filled with air lets the pressure balance, which helps prevent solution loss at the stopper.
3. Add the solvent slowly. Direct the liquid gently down the inside wall of the vial rather than straight onto the powder.
4. Swirl — do not shake. Gently rotate the vial until fully dissolved. Vigorous shaking can disrupt the peptide’s structure.
5. Allow full dissolution. If any particles remain, gentle further swirling (or brief sonication) can help complete dissolution.

Choosing a Solvent

Bacteriostatic water is the most commonly used reconstitution solution for general laboratory work. Some peptides with poor solubility may require a small amount of dilute acetic acid to dissolve fully, and a higher-concentration stock solution can then be diluted with an appropriate assay buffer as needed. Our Bacteriostatic Water is available to support reconstitution.

Reconstitution Calculator

Enter the amount of peptide in your vial and the volume of solvent you plan to add. The calculator returns the resulting concentration and, optionally, the volume that contains a target research quantity.

Peptide Stability & pH Estimator

This tool gives a rough, research-oriented estimate of how long a peptide may remain stable based on its form, storage temperature and solution pH. Peptides are generally most stable at a mildly acidic to neutral pH (around 5–7); strongly acidic or alkaline conditions tend to reduce stability. Estimates are general guidance only and are not a guarantee for any specific compound.

General Storage Duration Guidance

Additional Handling Notes

For solutions where trace particles remain after swirling, brief sonication can aid complete dissolution. Where sterility of a solution matters to the research application, filtration through a 0.2 µm filter is a common step. Avoid adding excessive solvent volumes, and keep reconstituted material refrigerated between uses. For details on the documentation supplied with each batch, see Quality & Testing and our article on Certificates of Analysis.