How to Store Research Peptides
A practical guide to keeping lyophilised and reconstituted peptides stable — temperatures, light, and shelf life in a research context.
Peptides are delicate molecules. Improper storage is one of the most common reasons a research peptide loses potency before it’s ever used. The good news is that the rules are simple and mostly about temperature, moisture, and light.
Lyophilised (freeze-dried) powder
In their shipped, freeze-dried state most peptides are remarkably stable. The absence of water dramatically slows the chemical reactions — hydrolysis, oxidation, aggregation — that degrade peptide bonds.
- Short term (weeks): room temperature, away from direct light, is usually acceptable for shipping and brief handling.
- Medium term (months): refrigerate at 2–8 °C in a sealed, desiccated container.
- Long term (years): freeze at −20 °C or colder. Many labs use −80 °C for multi-year storage.
Always let a cold vial return to room temperature before opening it. Opening a cold vial lets ambient moisture condense onto the powder, which is exactly what you’re trying to avoid.
Reconstituted solution
Once a peptide is dissolved — typically in bacteriostatic water — the clock starts. Water reintroduces the very reactions that lyophilisation prevented.
- Keep reconstituted solutions refrigerated at 2–8 °C.
- Most are reasonably stable for a few weeks refrigerated, though this varies widely by sequence.
- Avoid repeated freeze–thaw cycles, which mechanically stress and aggregate peptides. If long-term storage of a solution is needed, aliquot into single-use portions first.
Enemies of stability
| Factor | Why it matters |
|---|---|
| Heat | Accelerates hydrolysis and oxidation |
| Moisture | Enables degradation of the dry powder |
| Light (UV) | Damages aromatic and sulfur-containing residues |
| Repeated freeze–thaw | Promotes aggregation |
| Oxygen | Oxidises methionine, cysteine, tryptophan |
Signs of degradation
Cloudiness, visible particulates, or discoloration in a previously clear solution suggest aggregation or contamination. A degraded peptide may simply be inactive, so visual inspection before use is good practice.
This guide is provided for laboratory research reference only. See our disclaimer.