Key takeaways
- Store sealed lyophilized peptides cold, dry and dark, commonly at −20 °C long-term.
- Let vials reach room temperature before opening to avoid condensation.
- Once dissolved, aliquot and avoid repeated freeze–thaw cycles.
- Met, Cys and Trp oxidize; Asn and Gln deamidate. Handle those sequences with extra care.
Most research peptides are supplied as a lyophilized (freeze-dried) powder. Dry, they are far more stable than in solution, but how they are stored, opened and prepared still has a large effect on how long they keep their integrity.
Storage at a glance
| Form | Typical storage | Notes |
|---|---|---|
| Lyophilized, sealed | −20 °C long-term; 2–8 °C short-term | Keep dry and away from light |
| Lyophilized, opened | Reseal tightly, return to cold storage | Minimize air and moisture exposure |
| In solution | 2–8 °C short-term; frozen aliquots longer | Avoid repeated freeze–thaw; rely on validated stability data |
What breaks peptides down
Freeze–thaw cycles add stress on top of all of these, especially once a peptide is in solution. Some laboratories store lyophilized stock at −80 °C for the longest-term holdings.
Opening a vial the right way
- Let it warm up sealedBring the vial to room temperature, ideally in a desiccator, before opening. Cold powder pulls condensation from room air.
- Work quicklyWeigh or dispense what you need without leaving the vial open.
- Reseal and returnClose tightly and put the vial back into cold, dark storage.
- Record the lotNote the lot number with your preparation records so results trace back to the batch COA.
Preparing solutions in the lab
- Choose the solvent for the sequence. Sterile distilled water suits many peptides; very hydrophobic sequences may need a small amount of organic co-solvent, and strongly acidic or basic peptides may dissolve better with a little dilute acid or base before buffer is added.
- Add buffer after the peptide has fully dissolved.
- Dissolve gently. Swirl or briefly sonicate rather than shaking hard, which can promote aggregation.
- Keep solution pH roughly 5–7 for storage, unless the compound’s documentation says otherwise.
Laboratory supplies such as AH-Recon reconstitution solution are listed in Research Supplies. Always confirm the label, ingredients and storage instructions against your protocol.
Sequences that need extra care
| Residue | Risk | Precaution |
|---|---|---|
| Methionine (Met) | Oxidation | Degassed solvent, limit air exposure |
| Cysteine (Cys) | Oxidation, disulfide formation | Oxygen-free solvent, prepare fresh |
| Tryptophan (Trp) | Oxidation, light sensitivity | Protect from light |
| Asparagine, Glutamine | Deamidation over time | Shorter solution storage |
| Copper peptides (GHK-Cu) | Light and pH sensitivity | Store dark, avoid strong acid or base |
Peptides containing these residues generally have a shorter usable life in solution. Preparing smaller volumes more often is the safer approach.
Signs a peptide may have degraded
- Cloudiness, haze or particles in a solution that should be clear
- A change in color
- Powder that looks wet, sticky, shrunken or collapsed
- A cracked seal or loose cap on arrival
Degradation isn’t always visible. If a preparation’s history is uncertain, discard it and start from a fresh, properly stored vial.
Receiving a shipment
Room temperature is tolerated by lyophilized peptides for the few days of normal transit, but it isn’t a storage condition. Move vials into cold, dark storage as soon as they arrive, rather than leaving them in a warm mailbox or vehicle. Check that the seal is intact and that the lot number on the vial matches its COA before logging it into inventory.
Related resources
All After Hours Labs products are sold strictly for qualified in-vitro laboratory research. They are not for human or veterinary use, and nothing in this article is medical advice or a recommendation for use in people or animals.
