Storing and Reconstituting Research Peptides Without Losing Potency
Most peptide degradation happens after delivery, not during shipping. Storage temperature, diluent selection and handling discipline determine whether a 99% pure batch still behaves like one on the day you use it.
Lyophilized storage
Keep sealed lyophilized vials at −20 °C, protected from light and moisture. For storage beyond three months, −80 °C is preferable. Allow vials to reach room temperature before opening; condensation on cold powder introduces water that accelerates hydrolysis.
Choosing a diluent
Sterile or bacteriostatic water suits most sequences. Peptides with hydrophobic residues may need a small proportion of acetonitrile or dilute acetic acid before dilution into buffer. Strongly acidic or alkaline diluents can hydrolyse sensitive residues, so check the sequence before selecting one.
Add the diluent slowly against the vial wall rather than directly onto the powder, and swirl instead of shaking. Vigorous agitation denatures peptides and drives aggregation.
Aliquot before you freeze
Freeze–thaw cycling is the most common avoidable cause of potency loss. Divide reconstituted material into single-use aliquots immediately, label each with the batch reference, and freeze once. Refrigerated solutions are typically usable for two to three weeks depending on sequence.
Documenting handling for reproducibility
Record reconstitution date, diluent, concentration and storage temperature alongside the batch reference. When an assay drifts, this log is what lets you distinguish a material problem from a protocol problem.
Frequently asked questions
Short answers to the questions laboratories ask most often about this topic.
How long do reconstituted peptides last?
Typically two to three weeks at 2–8 °C, or several months at −20 °C when aliquoted and frozen only once. Sequence stability varies, so check the product documentation.
Can peptides be stored at room temperature?
Lyophilized peptides tolerate short transport periods at ambient temperature, but sustained room-temperature storage causes measurable degradation. Transfer to −20 °C on arrival.
What water should be used to reconstitute a peptide?
Bacteriostatic water is standard for multi-use handling; sterile water or a defined buffer is preferable where preservatives would interfere with the assay.
How long does reconstituted peptide last?
Typically two to three weeks at 2–8 °C for stable sequences, and far less for fragile ones. Aliquoting and freezing extends usable life considerably.
Does freeze–thaw cycling really damage peptides?
Yes. Each cycle concentrates solutes and promotes aggregation, which is the most common preventable cause of lost activity in laboratory stocks.
Can lyophilized vials be stored in a domestic freezer?
A −20 °C freezer without auto-defrost is acceptable for short-to-medium term storage; frost-free units cycle temperature and should be avoided.
Peptides supplied with lot-specific analysis
Every PureLabs batch ships with an independent HPLC and mass-spectrometry certificate tied to the reference printed on your vial.