Lyophilized Peptide Storage Guide for Laboratory Research

Lyophilized research peptides are stable when stored correctly and degrade quickly when they are not. This guide covers storage temperature, freeze-thaw behavior, aliquoting, and reconstituted handling for the laboratory. It is research-use guidance for material handling only — not dosing or administration instruction. See the RUO policy.

Lyophilized (powder) storage

Short term (days to weeks): sealed vials are generally stable at 2–8 °C, protected from light and moisture.
Long term (months to years): store at −20 °C, or −80 °C for extended stability. Keep desiccated.
Allow vials to reach room temperature before opening to avoid condensation drawing water into the cake.

The lyophilized form is the most stable state, which is why peptides ship as a dry cake. Water content is reported on the CoA because it directly affects stability — see how to read a CoA.

Reconstituted (in solution) storage

Once reconstituted, store at 2–8 °C and use within the working window appropriate to the peptide and diluent.
For longer holds, aliquot and freeze at −20 °C or −80 °C to avoid repeated freeze-thaw.
Bacteriostatic water is commonly used as a research diluent because the benzyl alcohol limits microbial growth across multiple draws. Use the reconstitution calculator to determine diluent volume.

Freeze-thaw cycles

Each freeze-thaw cycle is a stress event. Repeated cycles promote aggregation and degradation, especially for longer or more hydrophobic sequences. The practical rule: aliquot once, thaw once. Prepare single-use aliquots from the reconstituted stock so each experiment draws from a vial that is thawed a single time.

Aliquoting workflow

Reconstitute the full vial with the calculated diluent volume.
Mix gently — swirl or roll; do not vortex aggressively.
Dispense single-use volumes into sterile, low-binding tubes.
Label each aliquot with compound, lot number, concentration, and date.
Freeze aliquots; keep one working aliquot at 2–8 °C if used within its window.

Handling notes

Protect light-sensitive peptides from prolonged light exposure.
Avoid repeated warming; keep stock cold during dispensing.
Record lot number against every aliquot for traceability back to the CoA.

FAQ

How long does lyophilized peptide last?

Stored desiccated at −20 °C or below, many lyophilized peptides remain stable for the advertised stability window and often beyond. Always defer to the lot CoA and your own SOP.

Can I refreeze a thawed aliquot?

Avoid it. Refreezing adds another stress cycle; prepare single-use aliquots instead.

What diluent should I use?

Choice of diluent is a research decision based on the peptide and assay. Bacteriostatic water is common for multi-draw research stocks.