Quick answer
Do peptides need refrigeration?
Reconstituted peptides: yes. Sealed lyophilized (freeze-dried) powder: not strictly short-term, but refrigeration is recommended.
On this page
Two states, two rules
Once reconstituted, keep the solution refrigerated (2–8 °C) and use within about two months. Sealed lyophilized powder is stable short-term at a cool room temperature, but lasts much longer refrigerated, or frozen (−20 °C) for the long term.
What to avoid
Heat, light and repeated freeze-thaw all degrade peptides. For the full breakdown see storing lyophilized peptides.
Frequently asked questions
Is it ruined if it sat out for a few hours?
A brief time at room temperature is usually fine, but prolonged heat or light degrades peptides. If a reconstituted solution looks cloudy or discoloured, discard it.