How to store research peptides
Lyophilised peptides are remarkably stable. In solution they are not. Nearly all real-world loss of potency comes from the period after reconstitution.
Before reconstitution
Sealed lyophilised vials are stable for 24 months or more at −20 °C, protected from light. At normal fridge temperature they remain stable for many months. Even at room temperature, a sealed lyophilised vial tolerates the few days of a shipping journey without meaningful loss — which is why peptides ship without cold packs.
After reconstitution
Once in solution, store at 2–8 °C and use within 28 days as a general rule. Keep the vial upright, in the dark, and away from the fridge door where temperature swings are largest.
Freeze-thaw cycles
Each freeze-thaw cycle costs a little potency. If you need to store a reconstituted peptide long term, aliquot it into single-use portions first, then freeze those — so you thaw only what you need.
Light and moisture
Some compounds, notably GHK-Cu and Semax, are strongly hygroscopic and light-sensitive. Keep them in their original amber packaging and reconstitute promptly once opened.