How to Store Peptides: Lyophilized and Reconstituted
Correct storage protects peptide potency. Here is how to store lyophilized and reconstituted peptides, and how storage relates to COA test dates.
Peptides are sensitive to heat, light, and moisture, and improper storage degrades potency before a research compound is ever used. Storage requirements differ between the dry lyophilized powder and the reconstituted solution. This is general educational information, not medical advice.
Storing lyophilized (dry) peptides
In their freeze-dried form, most peptides are stable for extended periods when kept cold and dry. Short term, a refrigerator is typically adequate; for long-term storage, a freezer is preferred. Keep vials away from light and avoid repeated temperature swings, which introduce moisture through condensation.
Storing reconstituted peptides
Once dissolved, peptides are far less stable and are generally kept refrigerated; if a stock must be kept longer, split it into single-use portions before freezing so it is never thawed and refrozen, because freeze-thaw cycles can damage the peptide in solution. Reconstituting with bacteriostatic water rather than plain sterile water extends the usable window. The exact shelf life after reconstitution varies by peptide.
What degrades peptides fastest
Heat and repeated freeze-thaw cycles are the biggest enemies, followed by light exposure and moisture. Shipping without cold packs in hot weather is a common, often invisible, source of degradation; our shipping score counts the stated dispatch time but does not measure packaging.
How storage relates to the COA
A Certificate of Analysis reflects the peptide at the moment of testing. A pristine COA does not guarantee what arrives at your door if the product was stored or shipped poorly afterward. Recent test dates and good shipping practices together give the most confidence.
Frequently Asked Questions
Should peptides be refrigerated or frozen?
Lyophilized (dry) peptides can be frozen for long-term storage. Reconstituted peptides are usually refrigerated; if a stock must be kept longer, it is split into single-use portions before freezing, since repeated freeze-thaw cycles can degrade peptide in solution.
How long do reconstituted peptides last?
It varies by peptide, but reconstituted peptides kept refrigerated and dissolved in bacteriostatic water generally last longer than those in plain sterile water. Confirm the specific peptide's stability.
Does poor shipping affect peptide quality?
Yes. Heat exposure during shipping can degrade a peptide even if its COA was perfect at testing. Our shipping score counts a vendor's stated dispatch time, but it does not measure packaging, so check how a vendor ships in hot weather.