How To Store
Research
Peptides
Lyophilised peptides are generally stored sealed, cold and protected from light. Once reconstituted into solution a peptide is far less stable, and is typically refrigerated and used within a limited window. Repeated freeze-thaw cycles are a common cause of degradation. Storage is the responsibility of the purchaser.
Why storage matters
Peptides degrade over time through hydrolysis, oxidation, deamidation and aggregation. Storage conditions determine how quickly. The goal of good storage is simple: slow every one of those processes down as far as practical. Cold, dark, dry and sealed is the general rule.
Storing lyophilised (dry) peptides
In dry, lyophilised form peptides are at their most stable. Standard practice is to keep them:
- Sealed — the cake is hygroscopic and will draw moisture from the air if the vial is opened and left, reintroducing the water that lyophilisation removed.
- Cold — refrigerated for shorter periods, frozen for longer-term storage.
- Dark — protected from light, which drives some degradation reactions.
Why dry material is so much more stable is covered in our guide to why research peptides are lyophilised.
Storing reconstituted (solution) peptides
Once a peptide is reconstituted the stability clock restarts — it is in water again, and degradation resumes. Solutions are therefore handled differently:
- Kept refrigerated and protected from light.
- Used within a limited window rather than stored indefinitely.
- Sometimes divided into single-use aliquots before freezing, so the whole stock isn't repeatedly warmed and cooled.
Freeze-thaw cycles
Each time a frozen peptide solution is thawed and refrozen, it is stressed — ice formation and the concentration changes that accompany it can promote aggregation. This is why solutions intended for freezing are often split into small aliquots first: each aliquot is thawed once and used, rather than the entire stock being cycled repeatedly.
Storage, handling and disposal in a research setting are the responsibility of the purchaser.
Frequently Asked Questions
Lyophilised peptides are generally stored sealed, cold (refrigerated for shorter periods, frozen for longer term) and protected from light. Keeping the vial sealed prevents the hygroscopic cake from drawing in moisture.
Reconstituted peptides are far less stable than dry material and are typically refrigerated, protected from light and used within a limited window rather than stored long term. The exact period depends on the compound and conditions.
A freeze-thaw cycle is thawing a frozen solution and refreezing it. Each cycle stresses the peptide and can promote aggregation. Dividing a solution into single-use aliquots before freezing avoids cycling the whole stock repeatedly.