Storing lyophilized peptides: temperature, moisture, and time
Lyophilization buys stability by removing water; every handling decision after that is a decision about letting water back in. A practical note on storage states, desiccation, and freeze-thaw discipline.
A lyophilized peptide is a dry glass. Its shelf life is a function of how well that glass stays dry and cold. Once reconstituted, the clock changes character entirely: hydrolysis, oxidation and microbial growth all become live failure modes.
Dry state
Published stability practice for lyophilized peptides favors storage at or below −20 °C, desiccated, protected from light. Under those conditions most research peptides retain stated purity for years; the dominant risk is not time but moisture ingress at each opening, which is why vials should equilibrate to room temperature before being opened.
Reconstituted state
In solution, peptides degrade on a timescale of days to weeks depending on sequence and temperature. Aliquoting once, freezing aliquots, and thawing each exactly once is the standard discipline; repeated freeze-thaw of a single working vial is the most common cause of irreproducible results in shared protocols.
What the label should tell you
- Storage temperature for the dry and reconstituted states.
- Batch code tying the vial to its certificate.
- Fill date or lyophilization date, so age is computable.