Storage cheat sheet — lyophilized vs reconstituted
Where to keep vials, how long they last, when to freeze (and when not to), and what heat exposure actually does.
Lyophilized (powder)
Refrigerated (2–8 °C) is the default. Most peptides remain stable 18–24+ months.
Room-temperature exposure during shipping is generally tolerated for a few days.
Freezing lyophilized vials at -20 °C extends shelf life for long-term storage. Avoid freeze-thaw cycles.
Reconstituted (liquid)
Refrigerate immediately after reconstitution. Standard shelf life is 28–30 days for most compounds.
Semaglutide and tirzepatide reference labeling extends to ~56 days refrigerated.
Do NOT freeze reconstituted peptides — ice crystals fragment the peptide chain.
Protect from light (an opaque box in the fridge is enough).
Signs a vial is compromised
Cloudy solution that does not clear with gentle swirling.
Visible particulates, strands, or a color shift.
Off smell on the stopper.
When in doubt: discard. A ruined vial is cheaper than a bad research outcome.