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Peptide Storage and Handling: Powder, Solution and Travel
Peptides are fragile. Heat, light, moisture and rough handling all break them down. The rules change a lot once the powder is dissolved, so treat the two stages separately.
Freeze-dried powder
Sealed, freeze-dried peptides are much more stable than solutions. Many tolerate room temperature for days or weeks, for example during shipping. For longer storage, the usual advice is a freezer at about −20 °C, away from light and moisture.
Let a cold vial warm to room temperature before opening it so condensation does not form on the powder.
After reconstitution
- Keep the vial in the refrigerator at 2–8 °C. Do not freeze a reconstituted vial unless the compound notes say so; repeated freezing and thawing damages many peptides.
- Protect it from light by keeping it in the original box or a dark container.
- Many reconstituted peptides are used within about two to four weeks. Some, especially larger or less stable ones, should be used sooner.
- Wipe the stopper with an alcohol swab each time and use a fresh syringe every time.
Rules of thumb by situation
| Situation | What to do |
|---|---|
| Unopened powder, short term | Cool, dark, dry place; fridge if you can |
| Unopened powder, long term | Freezer at about −20 °C |
| Reconstituted vial | Fridge, 2–8 °C, protected from light |
| Travel for a day or two | Insulated pouch with a cold pack, not touching the vial |
| Power cut or warm day | If a solution sat warm for hours, treat it as compromised |
Signs a vial has gone bad
- Cloudiness or floating particles after it was clear.
- A change in colour.
- Visible mould or film in the liquid.
- A vial that was frozen, left warm for a long time, or has an unsealed stopper.
When in doubt, discard the vial. A replacement costs far less than a problem.
Label everything
Write the compound, the concentration and the date of reconstitution on each vial. Several vials look identical in the fridge, and a mislabelled vial is an easy way to get a dose wrong.
Common questions
Can I freeze a reconstituted peptide?
Generally avoid it. Repeated freezing and thawing can break peptides down. If you need to store a solution longer, ask whether the compound is suitable for aliquoting and freezing.
Does bacteriostatic water extend shelf life?
It lowers the risk of bacterial growth between draws, but it does not stop the peptide itself from slowly degrading.
Is it OK if powder arrives warm?
Short exposure is usually fine for freeze-dried powder. Move it to cold storage as soon as it arrives.
Try it
- Peptide Dosage Chart: Protocols for 100+ peptides, searchable by name and goal.
- Dosage Calculator: Vial size, water and dose in; mL and syringe units out, plus doses per vial.