Storage, stability and what -20°C actually buys you
Lyophilised peptides are far more robust than people assume in transit, and far more fragile than people assume in solution.
Working window by storage state
Handling guidance for typical lyophilised research peptides, not a measured stability claim. Sequence-dependent — Met- and free-Cys-containing sequences run shorter than this everywhere.
Source: PEPTiQX handling guidanceThe most common storage question we get is whether ambient shipping degrades material. For lyophilised powder, generally no.
## Dry powder is stable
Removing water removes the medium in which hydrolysis and most degradation chemistry happens. A properly lyophilised peptide tolerates days at ambient temperature without meaningful loss, which is why insulated ambient shipping is standard practice.
## Solution is where the clock starts
Once reconstituted, degradation resumes. Refrigerate at 2-8°C, keep the pH near neutral unless your protocol requires otherwise, and plan to use the solution within the window appropriate to the sequence.
## Light and moisture matter more than a few degrees
Repeated exposure to humid room air — opening a cold vial before it equilibrates, for instance — condenses water into the cake. Let vials come to room temperature before breaking the seal.
