Understanding How Long Do Peptides Last

Peptides, short chains of amino acids, are susceptible to various forms of degradation such as contamination, oxidation, and other destabilizing factors. To keep them in their most potent form it’s important to follow simple but effective guidelines.

Peptide Storage - Infographic

 

How Long Do Powdered Peptides Last?

Peptides in powdered form can stay viable for years when stored correctly. Freeze-dried (lyophilized) peptides maintain their stability for extended periods under ideal conditions. Research on peptide stability highlights the following:

Room Temperature Storage (68–77°F / 20–25°C): Peptides may begin to break down within weeks or months, depending on their composition and packaging.

Refrigerated Storage (36–46°F / 2–8°C): Most peptides can remain stable for about 1–2 years when kept in a refrigerator.

Frozen Storage (-4°F or -112°F / -20°C or -80°C): Freezing can extend peptide stability to 3–5 years or more. Studies indicate that peptides stored at -112°F (-80°C) have shown little to no degradation even after a decade.

Factors Affecting Peptide Stability

The stability and effectiveness of peptides depend on several factors, including their amino acid composition, environmental conditions, and storage methods. Certain amino acids, such as cysteine (Cys), methionine (Met), and tryptophan (Trp), make peptides more prone to degradation, especially when stored in solution. Their susceptibility to oxidation significantly reduces shelf life compared to other amino acid sequences.

In addition to composition, environmental conditions play an important role in peptide longevity. Factors like temperature, pH levels, and light exposure (particularly UV light) can accelerate degradation. Proper storage is essential to maintaining stability and preventing unwanted breakdown.

The choice of storage containers also impacts how long do peptides last. Glass vials offer the highest level of chemical resistance, making them the preferred option for long-term storage. While polypropylene vials may be better for transportation, glass vials outperform them in terms of prolonged storage.

Storing Lyophilized Peptides

Lyophilization involves freezing peptides and then removing water through sublimation under reduced pressure. This process helps preserve peptide integrity by minimizing hydrolytic degradation. The stability of lyophilized peptides is primarily achieved through:

·     Reduced Water Activity: Removing water prevents hydrolysis and reduces the activity of residual enzymes that could break down the peptide.

·     Controlled Environment: The process limits exposure to reactive oxygen species (ROS) and other environmental factors that can contribute to degradation.

While lyophilization greatly improves stability, peptides should still be stored carefully to prevent exposure to heat, moisture, and oxidation, which can impact their effectiveness over time.

Degradation of Lyophilized Peptides

While lyophilized peptides are more stable than those in solution, they are still susceptible to degradation over time. There are multiple reasons why peptides can degrade over time:

1.     Oxidation: Peptides containing methionine, cysteine, and tryptophan residues are especially vulnerable to oxidation. To minimize this risk, it’s important to store peptides in oxygen-tight containers that limit exposure to air.

2.     Aggregation: Peptides, particularly those with longer sequences, can experience aggregation due to hydrophobic interactions or improper folding during storage. This can lead to the formation of peptide clumps, affecting their effectiveness.

3.     Deamidation: This process involves the conversion of asparagine or glutamine to aspartic acid or glutamic acid. It is influenced by factors such as residual moisture and temperature, which can accelerate the degradation process.

How Long Do Reconstituted Peptides Last?

Once peptides are reconstituted, their stability can decrease significantly. Peptide solutions generally remain stable for up to 6 to 8 weeks when refrigerated at 4°C (39F). It’s advisable to use sterile buffers at a pH of 5-6 and to aliquot solutions to minimize exposure to freeze-thaw cycles. For long-term storage of solutions, freezing at -80°C (-112F) is optimal.

Peptide Storage Considerations

Reconstituting peptides can significantly reduce their stability, and exposure to air can accelerate oxidation. Therefore, it's important to keep the peptide container sealed as much as possible to minimize the risk of degradation.

Make sure the container is quickly resealed when you need to take a particular amount of peptide for your research. If possible, reseal the container using dry, inert gases such as argon or nitrogen. This can further reduce the chance of oxidation, although access to these gases may not always be feasible.

For moisture-sensitive peptides, extra care is needed since exposure to moisture can lead to degradation or hydrolysis. To maintain stability, store these peptides in a desiccator at low temperatures, ideally keeping them in their lyophilized powder form.

Peptides that are sensitive to light also require special attention. Light exposure, particularly UV light, can cause photodegradation. To protect these peptides, store them in opaque or amber-colored vials, and when not in use, ensure they are kept in a dark placed or wrapped in aluminum foil. This helps prevent light-induced breakdown and preserves the peptide’s effectiveness.

FAQ

How long do peptides last in powder form?

Lyophilized peptides stored at room temperature are stable for about up to a year without significant degradation. When refrigerated at under 4°C, their shelf life extends to 1-2 years, and they can last 2-3 years or indefinitely when frozen at -18°C and -80°C respectively.

How long do peptides last in the fridge?

Lyophilized peptides can be stored in the fridge for up to two years. For reconstituted peptides, the fridge can maintain their stability for about 30-60 days.

How long does reconstituted peptides last in the fridge?

Reconstituted peptides generally remain stable for up to 30-60 days when stored at 4°C, depending on the peptide's length and inherent instability factors.

How long do peptides last at room temperature?

Lyophilized peptides can last up to a year at room temperature. However, once reconstituted, their stability drastically reduces, and they should be refrigerated or used promptly.

How long do peptides last once reconstituted?

Once peptides are mixed with a solvent, they should ideally be used within 30 days when stored in the refrigerator. For longer storage, freezing at -80°C is recommended, though care must be taken to avoid multiple freeze-thaw cycles.

Conclusion

Proper storage is essential for maintaining the stability and integrity of peptides. By following the guidelines provided and utilizing tools like a reconstitution calculator, researchers can effectively manage their peptide stocks, ensuring that their experimental results remain reliable and consistent. When planning to buy peptides consider the storage requirements to maintain their efficacy over time.