Proper storage of a peptide can prevent bacterial degradation, secondary structure formation, oxidation, and other potential degradation for several years.
Peptides are most stable in their lyophilized form at -20° C or colder in a sealed container containing desiccant. If peptide must be stored in solution, ensure pH is in the 3-6 range and then aliquot peptide into usable sizes to prevent damage from multiple freeze/thaw cycles. Cysteine (C), methionine (M), tryptophan (W), asparagine (N), and glutamine (Q) are most sensitive to degradation in solution.
3 months-several years
Lyophilized powder, frozen and desiccated, -20° C or colder
Frozen liquid (-20° C) or refrigerated lyophilized powder