How to store peptides correctly — an NZ researcher's guide
Stored well, a research peptide retains full activity to the end of its shelf life. Stored poorly, the same compound can lose potency within weeks. This guide covers the practical cold-chain decisions NZ researchers face — from courier arrival to long-term freezer storage.
1. On arrival
- Inspect the seal and packaging for damage.
- Check that the vial contents are intact and not collapsed.
- Transfer lyophilised vials to a 2–8 °C fridge as soon as practical. They are stable at ambient for the courier window, but extended room-temperature storage shortens shelf life.
2. Lyophilised storage
| Temperature | Expected shelf life | Best for |
|---|---|---|
| Room temperature | Days – weeks | Transit only |
| 2–8 °C (fridge) | Up to ~3 months | Active stock |
| –20 °C (freezer) | 12–24 months | Long-term reserve |
| –80 °C (deep freeze) | 24+ months | Reference batches |
3. Reconstitution
Reconstitute under aseptic technique using sterile bacteriostatic water. The 0.9% benzyl alcohol suppresses microbial growth and is the standard diluent for multi-use vials. Direct the stream against the vial wall — not onto the lyophilised cake — and let the peptide dissolve without aggressive swirling.
4. Reconstituted storage
- Store at 2–8 °C, upright, protected from light.
- Label with the date of reconstitution and concentration.
- Use within 4–6 weeks unless the product's stability data supports a longer window.
- For longer storage, aliquot into single-use volumes and freeze at –20 °C. Do not refreeze a thawed aliquot.
5. Transport between sites
When moving vials between bench, fridge or off-site, an insulated carrier protects against temperature excursions. The Vantara safety case and peptide vial case are sized for standard 2 mL and 3 mL vials and accept a small ice pack.
Signs a peptide has degraded
- Cloudy or discoloured solution after reconstitution.
- Visible particulate.
- Loss of expected activity in assay.
- Foul odour on opening.
Protect your peptide investment
Everything you need to keep compounds stable from courier arrival to long-term storage.
Frequently asked questions
Do peptides need to be refrigerated during NZ shipping?
Lyophilised (freeze-dried) peptides are stable at ambient temperature for short transit windows, which is why they ship without ice packs domestically in New Zealand. Once received, transfer them to a 2–8 °C fridge for long-term storage.
Fridge or freezer — where should I store lyophilised peptides?
For storage up to ~3 months, 2–8 °C (fridge) is fine. For longer-term storage (6–24 months) a –20 °C freezer is preferable. Avoid frost-free freezers if possible, as their auto-defrost cycles introduce temperature swings.
How long does a reconstituted peptide last in the fridge?
Most reconstituted peptides remain usable for 4–6 weeks at 2–8 °C when diluted in bacteriostatic water and kept sealed. Confirm against the specific peptide's published stability data and your own validated protocol.
Can I freeze a reconstituted peptide?
Yes, but only once. Repeated freeze-thaw cycles degrade peptide structure. Aliquot into single-use volumes before freezing at –20 °C or colder.
Does light affect peptide stability?
Yes. UV and bright light can degrade certain residues (notably tryptophan and tyrosine). Always store vials in opaque packaging or a dark fridge compartment.