Research Guide
How to Store Peptides: Complete Storage Guide
Proper storage is critical for maintaining peptide integrity. Degradation from heat, moisture, light, and repeated freeze-thaw cycles can reduce purity and render peptides unsuitable for research. This guide covers optimal storage conditions for both lyophilized (powder) and reconstituted (liquid) peptides.
Lyophilized (Powder) Peptide Storage
Lyophilized peptides are the most stable form. At -20°C or colder, most lyophilized peptides remain stable for years. At 4°C (refrigerator), stability extends for months. At room temperature, peptides remain stable for weeks — meaning short-term temperature fluctuations during shipping do not typically compromise quality.
The primary enemies of lyophilized peptides are moisture and light. Store vials in sealed containers with desiccant packets. Keep away from direct light. When removing a vial from cold storage, allow it to reach room temperature BEFORE opening the cap — this prevents condensation (moisture) from forming on the cold powder inside.
Reconstituted (Liquid) Peptide Storage
Reconstituted peptides have limited stability compared to lyophilized form. At 4°C (refrigerator), most reconstituted peptides remain stable for 3-4 weeks. At -20°C (freezer), stability extends to 3-4 months. To maximize longevity, aliquot the reconstituted solution into single-use portions before freezing — this avoids repeated freeze-thaw cycles, each of which can degrade the peptide by 5-10%.
Factors That Degrade Peptides
Temperature: High temperatures accelerate chemical degradation (deamidation, oxidation, hydrolysis). Moisture: Water enables chemical reactions that break peptide bonds. Light: UV and visible light cause photo-oxidation, particularly of tryptophan, tyrosine, and methionine residues. Freeze-thaw cycles: Ice crystal formation during freezing can physically disrupt peptide structure. Contamination: Bacterial growth in reconstituted solutions consumes peptide material and introduces endotoxins.
Storage Temperature Quick Reference
Room temperature (20-25°C): Lyophilized peptides stable for weeks. Not recommended for reconstituted solutions.
Refrigerator (2-8°C): Lyophilized peptides stable for months. Reconstituted peptides stable for 3-4 weeks.
Freezer (-20°C): Lyophilized peptides stable for years. Reconstituted peptides stable for 3-4 months. Recommended long-term storage.
Deep freezer (-80°C): Maximum stability for both forms. Recommended for long-term archival storage of valuable compounds.
Frequently Asked Questions
Do peptides need to be refrigerated during shipping?▼
No. Lyophilized peptides are stable at room temperature for weeks. Standard shipping conditions (even during summer) do not compromise peptide integrity. Refrigerated shipping is only necessary for reconstituted (liquid) peptides.
How long do lyophilized peptides last at -20°C?▼
Most lyophilized peptides remain stable for several years at -20°C when properly sealed and protected from moisture. Stability varies by sequence — peptides containing methionine or asparagine residues may have shorter shelf lives due to oxidation and deamidation susceptibility.
Can I refreeze a peptide after thawing?▼
While possible, each freeze-thaw cycle degrades the peptide by approximately 5-10%. To avoid this, aliquot your reconstituted solution into single-use portions before freezing. This way, you only thaw what you need for each experiment.
All products are for Laboratory Research Use Only.
Not for human consumption, veterinary use, or diagnostic purposes.