Storing and Handling Lyophilized Peptides
Temperature, light, and moisture guidance for sealed lyophilized peptide vials, plus what to know about solvent choice and record-keeping after reconstitution.
Updated September 24, 2026
Long-term and short-term storage temperatures
Unopened, lyophilized (freeze-dried) peptide vials are stable for extended periods at −20°C. For shorter stretches — the days or weeks a vial might sit on a benchtop after shipment — 2–8°C (standard refrigeration) is generally adequate. Colder isn't automatically better once a vial has been reconstituted; see below. Steady conditions matter more than hitting an exact number: avoid storing a sealed vial somewhere temperatures swing significantly from day to day, such as near a window or an exterior wall.
Checking a vial on arrival
Before putting a new vial into storage, check that the batch or lot number on its label matches the one on the corresponding Certificate of Analysis. A cracked stopper, a broken seal, or visible powder loss are reasons to contact us right away, not reasons to store it as normal.
Desiccant and light
Lyophilized powder is hygroscopic — it draws moisture from the air, which degrades the cake over time. Keep the desiccant packet that ships with the vial in the same storage container, and keep vials in the box they arrived in or another light-blocking container. Many peptides are light-sensitive; UV and even ambient light exposure over weeks can degrade a sample left out on an open shelf.
Letting a vial warm before opening
Pull a vial from a fridge or freezer and let it sit, still sealed, until it reaches room temperature before opening it. Opening a cold vial immediately exposes the lyophilized cake to warmer, more humid room air, and condensation can form inside — introducing moisture exactly where you don't want it.
Reconstitution: solvent choice, not procedure
Once a peptide is reconstituted (dissolved), it's chemically distinct from its dry powder state, and how it should be stored changes accordingly. Solvent selection depends on the peptide's sequence and the assay; DexaLabs does not specify volumes or concentrations. Common solvent choices include bacteriostatic water, sterile water, and dilute acetic acid for basic peptides.
Avoiding repeated freeze and thaw
Repeated freeze–thaw cycles degrade peptides in solution; minimise them.
Labelling and record-keeping
Write the reconstitution date directly on the vial or its container the moment it's dissolved. A lyophilized vial can sit correctly labelled for a long time with no ambiguity about its state; a reconstituted one without a date on it is a gap in the record.
Waste disposal
Dispose of empty vials, unused solution, and any related consumables according to your institution's own biological and chemical waste rules. DexaLabs doesn't set disposal policy — your institution's own EHS office does.