The stability of peptide products begins to decline from the moment they are received. Proper storage is essential for maintaining their activity.
Most peptide products are supplied as lyophilized (freeze-dried) powders. Although relatively stable in this state, they remain susceptible to environmental factors. The optimal method for long-term storage is freezing at -20°C, which preserves activity for months or even years. For short-term use, storage under refrigeration at 2–8°C is sufficient. Regardless of the method, protection from light and moisture is crucial; exposure to light and humidity accelerates degradation, so keeping the product in its original packaging or wrapping it in aluminum foil provides the best protection.
However, once the lyophilized powder is reconstituted with sterile water, the storage rules change fundamentally. Reconstituted peptides must be stored at 2–8°C and should never be refrozen. Ice crystals formed during freezing can damage the peptide's molecular structure, leading to an irreversible loss of activity. If reconstituted with bacteriostatic water (BAC water), most peptides remain stable under refrigeration for 7 to 14 days; if standard saline is used, they should be used within 24 to 48 hours. Always use a sterile needle when withdrawing the solution to prevent contamination.
In summary, keep two principles in mind when storing peptide products: lyophilized powders can be either frozen or refrigerated, but reconstituted solutions must be refrigerated; throughout the process, ensure protection against light, moisture, and contamination. Following these guidelines will maximize the preservation of peptide activity.