Knowing how to store peptides correctly protects their integrity. Lyophilised (freeze-dried) powder and reconstituted solutions have different requirements — the guidance below reflects standard laboratory practice.
Peptide storage at a glance
| State | Temperature | Typical usable window |
|---|---|---|
| Lyophilised powder (long-term) | -20°C or colder, sealed & dry | Months to years |
| Lyophilised powder (short-term) | 2–8°C (refrigerated) | Days to weeks |
| Reconstituted solution | 2–8°C, protected from light | ~30 days (sooner for less stable peptides) |
Do peptides need refrigeration?
Sealed lyophilised powder is stable enough to ship at ambient temperature for a few days, which is why vials often arrive at room temperature. For anything beyond short-term handling, though, peptides should be kept cold — refrigerated for the short term and frozen at -20°C or colder for long-term storage. Once a peptide is reconstituted it should always be refrigerated.
Storing lyophilised (powder) peptides
- Long-term: store at -20°C or colder, sealed and dry, protected from light.
- Short-term: a few days to weeks are generally tolerated at refrigeration (2–8°C) or, briefly, at room temperature during shipping.
- Always let a cold vial return to room temperature before opening to stop condensation drawing moisture into the powder.
Storing reconstituted (solution) peptides
- Refrigerate at 2–8°C and use within roughly 30 days as a general rule; some peptides are less stable and should be used sooner.
- Divide into single-use aliquots to avoid repeated freeze–thaw cycles.
- Keep solutions out of the light and reseal promptly after each draw.
Work out your concentration and aliquot sizes with the reconstitution calculator, and see the reconstitution guide for technique. For diluent choice, see bacteriostatic water vs sterile water.
Avoiding freeze–thaw damage
Repeated freezing and thawing is one of the most common causes of peptide degradation. Aliquot reconstituted material into single-use portions so each is thawed only once, and avoid frost-free freezers, whose automatic defrost cycles fluctuate in temperature.
Protecting against oxidation, moisture and light
Sequences containing cysteine, methionine or tryptophan are more prone to oxidation — minimise air exposure and reseal promptly. Keep material “cold, dry and dark,” and use silica desiccant in the storage container to control moisture.
Containers
Sterile glass vials are ideal. Where plastic is used, polypropylene resists chemical interaction better than polystyrene.
Shelf life and the Certificate of Analysis
Shelf life depends on the specific peptide and its storage conditions. Every BioSequence Labs lot ships with a lot-specific Certificate of Analysis documenting its verified identity and purity at release.
Frequently asked questions
Do peptides need to be refrigerated?
Sealed lyophilised powder tolerates short periods at ambient temperature, but for storage beyond a few days peptides should be refrigerated (2–8°C) or frozen at -20°C for the long term. Reconstituted solutions should always be refrigerated.
How long do reconstituted peptides last?
As a general rule, refrigerated reconstituted peptide is used within about 30 days, though less stable sequences should be used sooner. Aliquoting and avoiding freeze–thaw cycles extends usable life.
Can peptides be stored at room temperature?
Only briefly, such as during shipping. For anything longer, cold storage is needed to preserve integrity.
Part of our research peptides handbook.