Peptide Storage and Reconstitution Best Practices

Lyophilized peptides are remarkably stable when stored properly. The standard recommendation is -20°C in the original sealed vial, protected from light and moisture. Frost-free freezers cycle temperature — use a manual-defrost unit when possible.

For reconstitution, USP-grade bacteriostatic water (0.9% benzyl alcohol) is the most common diluent. Add the diluent slowly down the side of the vial to avoid foaming, then gently swirl — do not shake. Vigorous agitation can denature larger peptides.

Working stocks are most stable at 2–8°C and should generally be used within two to four weeks. For longer storage of working stocks, aliquot into single-use volumes and freeze at -20°C to avoid freeze-thaw degradation.

Label every aliquot with peptide name, concentration, lot number, and reconstitution date. This is basic GLP hygiene that pays dividends when troubleshooting variable results months later.