Storage and stability
Most material is degraded by handling, not by anything wrong with the batch. These are the variables that matter.
- What is lyophilisation?
- What does lyophilised mean?
- Why do peptides ship as a powder?
- What is the cake at the bottom of a peptide vial?
- How do you store research peptides?
- What are the most common peptide storage mistakes?
- Does light or heat damage peptides?
- Do freeze-thaw cycles damage peptides?
- Do peptides need to stay cold in shipping?
- Why are peptides in glass vials and not plastic?
What is lyophilisation?
Lyophilisation, or freeze-drying, removes water from a frozen sample by sublimation under vacuum — ice becomes vapour without passing through a liquid phase. It leaves a dry, porous solid. Because degradation reactions need water, removing it is what makes a peptide storable for long periods.
What does lyophilised mean?
Lyophilised means freeze-dried. The material arrived as a solution, was frozen, and had its water removed under vacuum, leaving a dry solid. A lyophilised peptide is stable far longer than the same peptide in solution, which is why it ships in that form.
Why do peptides ship as a powder?
Because water drives the reactions that break peptides down. Hydrolysis, oxidation and aggregation all need a solvent to proceed. Removing the water by freeze-drying effectively pauses them, so a lyophilised peptide survives shipping and storage in a way the same peptide in solution would not.
What is the cake at the bottom of a peptide vial?
The cake is the dry porous solid left after freeze-drying. Appearance varies legitimately — a solid disc, a fluffy layer, or a thin film all occur depending on fill volume and cycle. What is worth noting is a change from a documented appearance, or visible moisture, which suggests the seal has been compromised.
How do you store research peptides?
Lyophilised material keeps best cold, dark and dry, in its sealed vial. Once reconstituted, storage life shortens dramatically and refrigeration becomes necessary rather than optional. Let a cold vial reach room temperature before opening, so atmospheric moisture does not condense onto the powder.
What are the most common peptide storage mistakes?
Three recur: opening a cold vial straight from the fridge so moisture condenses inside, leaving reconstituted material at room temperature, and repeatedly freezing and thawing one vial. All three are handling errors rather than material defects, and all three are avoidable.
Does light or heat damage peptides?
Both accelerate degradation. Heat speeds up the chemical reactions that break peptide chains and drive aggregation. Light, particularly UV, can damage specific light-sensitive residues. Neither effect is instant, but both are cumulative — which is why cool, dark storage is the standard recommendation.
Do freeze-thaw cycles damage peptides?
Yes, cumulatively. Each cycle concentrates solutes at the ice boundary and puts mechanical stress on the molecule, encouraging aggregation and loss of activity. The standard mitigation is to split reconstituted material into single-use aliquots so each portion is thawed exactly once.
Do peptides need to stay cold in shipping?
Lyophilised peptides tolerate short periods at ambient temperature far better than material in solution, so brief transit without refrigeration is not automatically a problem. Cumulative time and temperature are what matter — which is why long, uncontrolled transits and unpredictable customs delays are the real risk.
Why are peptides in glass vials and not plastic?
Glass is chemically inert, so it does not leach plasticisers into the contents or adsorb peptide onto its surface the way some plastics can. It also seals reliably against moisture and tolerates the temperature range of a freeze-drying cycle. For low-concentration peptide work, surface adsorption is a real loss.