How should peptides be stored and what are the stability requirements?

Lyophilized (freeze-dried) peptides should be stored at -20°C or colder, protected from light and moisture, where they can remain stable for 2-3 years or longer. Once reconstituted, peptides are much less stable and should be refrigerated at 4°C for no more than 1-2 weeks, or frozen at -20°C for 3-4 months. To maximize stability, aliquot reconstituted solutions into smaller volumes to avoid repeated freeze-thaw cycles, which accelerate degradation.