Storing Lyophilized Peptides: Temperature, Light and Shelf Life

Why lyophilized material ships at ambient temperature, what changes after reconstitution, and what the stability figures actually mean.

Why lyophilized material ships at ambient temperature

Lyophilisation — freeze-drying — removes water under vacuum, leaving a dry cake or powder. Most of the degradation routes that affect peptides need water to proceed, so removing it makes the material far more stable than the same peptide in solution.

This is why lyophilized peptides are shipped without cold-chain handling and arrive intact after several days in transit. The dry state, not the temperature, is doing the work.

Storage of sealed, unreconstituted vials

For longer-term storage the variables that matter are temperature, moisture and light.

• Keep vials sealed — the stopper is what keeps atmospheric moisture out
• Cold is better than warm, and consistently cold is better than cycling
• Keep them dry; condensation on a cold vial brought into a warm room is a real route for moisture ingress
• Keep them out of direct light; some sequences are photosensitive
• Avoid repeated freeze–thaw cycles

What changes once material is in solution

Reconstituted peptide is a fundamentally different storage problem from dry powder. In solution, hydrolysis, oxidation and aggregation all become available, and stability is measured in days or weeks rather than months or years.

Specific figures depend on the sequence, the solvent and the concentration, which is why general stability tables are only ever indicative. The product certificate and the published literature for a given compound are the better reference.

Reading a stability table

Stability figures are typically given as a time at a temperature — for instance a shelf life for sealed lyophilized material at a stated storage temperature. They describe material held under those conditions, not material that has been opened, warmed, refrozen or left on a bench.

Our general figures are on the Storage & Handling page.