How to Store Peptides at Home
Peptides are sensitive to temperature, light, and humidity. We break down how to properly store lyophilizate and reconstituted solution.
Lyophilizate: before reconstitution
Peptide manufacturers (Bachem, Sigma-Aldrich, GenScript, and other reagent suppliers) agree on the general guidance: for long-term storage, lyophilizate should be kept in a tightly sealed container below −15 °C, and preferably at −20 °C or lower. Because peptides are hygroscopic (they absorb moisture from the air), it's recommended to take the container out of the freezer and let it warm to room temperature while still sealed (ideally in a desiccator) before opening, to avoid condensation on the powder.
After reconstitution
Once reconstituted, a peptide's stability drops noticeably. The general rule from reagent suppliers: stored in a refrigerator (around 4 °C), a solution stays stable for about a week; for longer storage, the solution is frozen in individual portions to avoid repeatedly thawing the whole volume. Reconstitution is typically done at room temperature (around 25 °C), which speeds up full dissolution.
What deserves special attention
Peptides with cysteine, methionine, or tryptophan residues in their structure are more prone to oxidation and require storage without oxygen exposure. Peptides with aspartic acid, glutamic acid, lysine, arginine, or histidine residues, on the other hand, tend to absorb moisture from the air — airtight packaging matters especially for these. Light also accelerates degradation in many peptides, so storing them in their original opaque packaging isn't a formality — it's part of the stability protocol.
A short checklist
Keep lyophilizate in the freezer until use; let the container warm to room temperature before opening; store reconstituted solution in the refrigerator and use it within a few days — for longer storage, freeze it in portions; avoid direct light and repeated freeze-thaw cycles of the same portion.