How to Store Peptide Pens and Vials: A Laboratory Guide

Peptides are delicate molecules. Heat, light, moisture and repeated freeze-thaw cycles can all degrade a sample, so storage directly affects the quality of your results. This guide covers the three formats researchers work with most: lyophilised vials, reconstituted solutions and pre-filled pens. Where the label or certificate of analysis gives different storage information, follow that.

Lyophilised (freeze-dried) vials

In dry powder form most peptides are at their most stable.

• For longer-term storage, keep sealed vials frozen at around -20°C.
• For shorter periods, refrigerate at 2-8°C.
• Keep vials in their box or another dark container to protect them from light.
• Let a cold vial reach room temperature before opening so moisture does not condense on the powder.

Reconstituted solutions

Once a peptide is dissolved, for example in bacteriostatic water, it becomes less stable.

• Refrigerate at 2-8°C and keep away from light.
• Avoid repeated freezing and thawing; if you need to freeze, split the solution into single-use portions first.
• Label each vial with the compound, concentration and date of preparation.

Pre-filled peptide pens

A peptide pen holds the compound already in solution, so treat it like a reconstituted sample.

• Keep pens refrigerated at 2-8°C unless the label says otherwise, and do not freeze them.
• Keep the cap on to protect the cartridge from light and contamination.
• Note the date a pen was first used and follow the use window on the label.

Handling tips

Minimise the time samples spend out of the fridge, use clean technique every time a vial or pen is accessed, and discard any solution that turns cloudy or shows particles.

Related guides

Choosing a format? Read peptide pens vs vials. Checking a batch? See what a certificate of analysis tells you. Browse Alluvi and Synedica pens or the full catalogue. All products are for laboratory research use only.