Peptides are biological molecules. Unlike small-molecule chemicals that can sit on a shelf indefinitely, peptides degrade over time through predictable chemical pathways: oxidation, hydrolysis, deamidation, and aggregation. Proper storage slows these processes. Improper storage accelerates them.

A peptide that tests at 99.2% purity on the day of manufacture can drop below usable purity within weeks if stored improperly. The same peptide stored correctly can remain stable for months to years. The difference is entirely within the researcher's control.

This guide covers the fundamentals: temperature, light, moisture, reconstitution, and the specific considerations that vary by peptide type.

Lyophilized (Freeze-Dried) — Most Stable

Most OSYRIS peptides ship as lyophilized powder — a dry, fluffy solid produced by freeze-drying a peptide solution. Lyophilization removes virtually all water from the product, which is significant because water participates in most degradation reactions (hydrolysis, deamidation). Without water, these reactions cannot proceed.

Lyophilized peptides are your most stable form. They tolerate temperature fluctuations better than solutions, resist oxidation better (fewer dissolved oxygen molecules), and have the longest shelf life. Always keep peptides in lyophilized form until you're ready to use them.

Storage for lyophilized peptides:

• Short-term (weeks to a few months): 2-8°C (standard refrigerator)
• Long-term (months to years): -20°C (standard freezer) or -80°C (ultra-low freezer)
• Light: Protect from direct light. Keep vials in their box or wrap in foil
• Moisture: Keep sealed. Do not open vials in humid environments. Allow vials to reach room temperature before opening to prevent condensation from being drawn into the vial

Reconstituted (In Solution) — Less Stable

Once you dissolve a lyophilized peptide in a solvent (typically bacteriostatic water, sterile water, or DMSO), the clock starts. Water reintroduces hydrolysis and deamidation pathways. Dissolved oxygen accelerates oxidation. Bacterial contamination becomes possible.

Storage for reconstituted peptides:

• Temperature: 2-8°C (refrigerator). Never store reconstituted peptides at room temperature
• Duration: Use within 2-4 weeks for most peptides. Some peptides (notably BPC-157) have better solution stability than others
• Light: Protect from light — wrap in foil or store in a dark container
• Sterility: Use aseptic technique during reconstitution. Bacteriostatic water (containing 0.9% benzyl alcohol) provides some protection against microbial growth. Sterile water without preservative should be used more quickly
• Freeze-thaw: Avoid repeated freeze-thaw cycles with reconstituted peptides. Each cycle can cause aggregation and degradation. If you need to store reconstituted peptide longer, aliquot into single-use portions before freezing

In Transit — The Vulnerable Window

Peptides are most vulnerable during shipping. Temperature control, light exposure, and physical agitation are all variables. OSYRIS ships lyophilized peptides (the most stable form) with temperature-conscious packaging. Upon receipt, transfer products to appropriate storage immediately.

Understanding why peptides degrade helps you prevent it:

Oxidation — The most common degradation pathway. Methionine, cysteine, tryptophan, and histidine residues are particularly susceptible. Oxygen dissolved in solution or in the headspace of a vial reacts with these residues, altering the peptide's structure and potentially reducing activity. Prevention: minimize oxygen exposure, use inert gas (nitrogen or argon) to displace headspace, store at low temperatures.

Hydrolysis — Water molecules break peptide bonds, fragmenting the chain. This is why lyophilized (dry) peptides are more stable than solutions. Prevention: keep peptides dry until use, minimize time in solution.

Deamidation — Asparagine and glutamine residues spontaneously convert to aspartate and glutamate, respectively, in the presence of water. This is a time-dependent process that accelerates at higher temperatures and non-physiological pH. Prevention: store at low temperatures, use appropriate buffer pH (if applicable to your protocol).

Aggregation — Peptide molecules can clump together, particularly after freeze-thaw cycles or at high concentrations. Aggregated peptides may have reduced activity and altered solubility. Prevention: avoid repeated freeze-thaw, use appropriate concentrations, aliquot before freezing.

Not all peptides have the same stability profile. Some OSYRIS products require special attention:

NAD+ (Solution Form) — Unlike most OSYRIS products, NAD+ ships in solution, not lyophilized. Store at 2-8°C continuously. NAD+ is more temperature-sensitive than most peptides. Do not freeze NAD+ solution unless specifically directed by your protocol.

GHK-Cu (Copper Complex) — The copper ion in GHK-Cu is relatively stable but can be displaced under certain conditions (extreme pH, competing chelators). Store under standard peptide conditions.

Blends (BPC/TB500, GLOW, KLOW) — Multi-peptide blends follow the same storage rules as individual peptides. The most sensitive component dictates the storage conditions for the blend. Store at -20°C for long-term.

GLP Compounds (GLP-1 (S), GLP-2 (T), GLP-3 (R)) — Larger peptides (>4000 Da) can be more susceptible to aggregation. Store at -20°C and avoid repeated freeze-thaw cycles.

Opening a cold vial immediately. When you remove a vial from the freezer, condensation forms on and inside the vial as warm, humid air contacts the cold surface. This moisture can degrade lyophilized peptide. Always let vials equilibrate to room temperature (15-20 minutes) before opening.

Storing reconstituted peptide at room temperature. Even briefly. Degradation rates roughly double with every 10°C temperature increase. A peptide stable for 4 weeks at 4°C might degrade significantly within days at 25°C.

Repeated freeze-thaw cycles. Each cycle introduces mechanical stress (ice crystal formation) and oxygen exposure. If you'll need multiple aliquots from one reconstitution, divide into single-use portions in separate tubes before freezing.

Using tap water or non-sterile diluents. Always use appropriate research-grade solvents. Bacteriostatic water is preferred for peptides that will be used over multiple days. Sterile water for single-use applications.

Storing in direct light. UV and visible light can photodegrade certain amino acid residues (tryptophan, tyrosine, phenylalanine). Keep vials in their box or wrapped in foil.