Peptide stability is one of the most overlooked variables in research. Here’s how storage conditions change your results. Lab reference only.
The Short Answer
Lyophilized (freeze-dried) peptides should be stored frozen at -20°C or colder and protected from light, while reconstituted peptides belong in the refrigerator and are far less stable. The single biggest mistake is leaving lyophilized peptides at room temperature.
Lyophilized vs Reconstituted
Freeze-dried peptide powder is stable for months to years frozen, but once you reconstitute it into solution, the clock starts and most peptides are only usable for days to weeks even refrigerated. This is the fundamental distinction in peptide storage.
- Lyophilized (powder): store frozen at -20°C or below, long shelf life
- Reconstituted (solution): refrigerate, use within days to weeks
- Both: keep away from light and repeated temperature swings
Freeze-Thaw Cycles
Repeated freeze-thaw cycles degrade peptides, so you should aliquot reconstituted solution into single-use portions and avoid re-freezing what you’ve already thawed. Each thaw costs you some integrity.
Common Storage Mistakes
The most common mistakes are storing powder at room temperature, leaving reconstituted solution out too long, and re-freezing thawed aliquots — all of which silently degrade the peptide. Poor storage is a common hidden cause of failed experiments.
- Storing lyophilized powder at room temperature
- Leaving reconstituted solution unrefrigerated
- Re-freezing thawed aliquots
- Exposing vials to direct light
FAQ
Q: How long do lyophilized peptides last?
A: Lyophilized peptides stored at -20°C or below typically remain stable for months to years, depending on the specific sequence. Check the COA for stability data.
Q: How long do reconstituted peptides last?
A: Once reconstituted, most peptides are stable for only days to weeks in the refrigerator, so plan to use them quickly. Don’t expect the same shelf life as powder.
Q: Should I freeze reconstituted peptides?
A: You can freeze aliquots, but avoid repeated freeze-thaw cycles — aliquot into single-use portions before freezing. Re-thawing degrades the peptide.