Lyophilized (unopened) material
Lyophilized research peptides are generally the most stable form. As a rule of thumb, laboratories store them cold and dry — commonly around −20 °C, kept desiccated and protected from light. Always defer to the storage guidance on the vendor’s COA or product page for the specific compound.
After reconstitution
Reconstituted material is less stable than the dry powder. Common lab practice is to aliquot immediately and keep aliquots frozen, using working aliquots within a short window and avoiding repeated freeze–thaw cycles, which can degrade peptides. Some sequences (for example cysteine-containing peptides) are more sensitive than others.
Bacteriostatic water and dedicated reconstitution solutions are the usual solvents for preparing research peptides in the lab. See our solvents category for options and where to buy them.