Lab Reference• 5 min read
Peptide Storage: Lyophilized vs. Reconstituted Shelf Life
Lyophilized peptides are stable for years if stored cold and dry. Once reconstituted, the clock starts. This page summarizes the storage windows most commonly used in research labs.
Lyophilized (powder) storage
- −20 °C freezer: 24+ months for most peptides
- 2–8 °C refrigerator: 6–12 months acceptable for shorter studies
- Room temperature in shipping (under 1 week): no meaningful degradation if vial stays sealed
Reconstituted storage
- Stable peptides (BPC-157, tesamorelin, semaglutide, retatrutide): 28 days at 2–8 °C
- Fragile peptides (GHK-Cu, oxytocin, ipamorelin): 14–21 days at 2–8 °C, shielded from light
- Freezing reconstituted peptide is possible but each freeze/thaw cycle causes measurable loss — preferable only for long studies
What kills potency fastest
- Heat — even a single 24-hour room-temp exposure for reconstituted vials reduces titer
- Light — UV degrades aromatic residues (tryptophan, tyrosine)
- Freeze/thaw cycles — each cycle precipitates a small fraction of peptide out of solution
- Bacterial contamination — why bacteriostatic water exists as a multi-use diluent