Most peptide raw materials travel as lyophilized powder in sealed vials, and buyer questions cluster around three moments: where to store the material, how it survives a week in a courier network, and what the receiving team should do when the box arrives. This guide covers those three moments from the buyer's side. It complements our earlier article on lab handling and in-formula stability; here the focus is the journey from the partner factory's freezer to your receiving record.
Why lyophilized powder travels well
Freeze-drying removes the water that drives the main degradation routes of a peptide in solution, so a sealed vial of dry powder tolerates time and temperature far better than the same peptide dissolved in buffer. The remaining risks are practical: moisture entering the vial, heat sustained over weeks rather than days, light for some sequences, and repeated freeze-thaw after reconstitution. Good packaging and a disciplined receiving process address all four.
Storage temperature: read the COA or TDS first
The storage line on the batch COA or technical data sheet is the only statement that reflects the stability data for that specific peptide. General patterns help you plan freezer space, but they never override the document.
| Form | Typical recommendation | Notes |
|---|---|---|
| Sealed lyophilized powder, long-term inventory | -20°C | The most common recommendation for peptide powders; keep desiccated and away from light |
| Sealed lyophilized powder, working stock | 2-8°C | For material that will be consumed within the period the supplier states |
| Some cosmetic-grade peptides | Controlled room temperature | Only when the COA or TDS explicitly says so |
| Reconstituted solution | 2-8°C short term, frozen aliquots for longer | Avoid repeated freeze-thaw of the same aliquot |
A supplier who cannot say which line applies to your lot, or show the stability data behind it, has given you a qualification finding.
How peptide shipments are packed
Standard export packaging for cold-stored peptides is an insulated box, usually expanded polystyrene inside a carton, with gel ice packs around the inner pack. Vials are sealed, often with desiccant in the secondary bag, and the batch label on each vial should match the outer carton. Dry ice is classed as dangerous goods for air transport and is rarely needed for lyophilized powder; it is reserved for specific products and agreed in advance.
International express normally takes several days door to door, and a customs hold can add more. Gel packs buffer the first part of that window; they are usually soft or fully thawed on arrival, and for sealed lyophilized powder this by itself is not a quality defect. Not every supplier includes a single-use temperature indicator card or data logger as standard, so if your quality system needs one, state it at the quotation stage.
What to check on arrival
Treat receiving as a short, repeatable procedure. This order keeps evidence intact if a claim is needed later.
- Inspect the outer carton for crushing, punctures, wet patches and broken tape, and photograph it before opening.
- Open the insulation and record the state of the ice packs, the arrival time and roughly how long the parcel sat at your dock.
- If an indicator card or logger is present, read it, photograph it and keep the record with the lot file.
- Count vials against the packing list, confirm the lot number matches on vial, carton and COA, and check that product name and CAS match your purchase order.
- Check each vial for an intact cap and seal, no cracks and a powder or cake that looks as the COA describes, with no visible moisture or sticky clumping.
- Confirm that the COA, safety data sheet, packing list and invoice are present and that the COA carries a manufacturing date and a retest date.
- Move the vials to the storage condition stated on the COA at once, and log the receipt.
| Observation | Usual reading | Action |
|---|---|---|
| Ice packs thawed, vials intact | Acceptable for sealed lyophilized powder | Record, photograph, store immediately |
| Indicator card tripped | Needs the supplier's stability data for that excursion | Hold the lot in correct storage, send the record the same day |
| Cracked vial, loose cap or wet powder | Not acceptable | Quarantine, photograph, raise a claim |
| Lot number differs between vial, carton and COA | Not acceptable until clarified | Do not release to the lab; ask for the matching documents |
Report any issue to the supplier the same day with photographs; a long gap between delivery and report blurs transit problems with storage problems on your side.
Retest date versus expiry date
Peptide COAs often carry a retest date rather than an expiry date. A retest date means the material should be re-analysed before use beyond that point; if it still meets specification, the supplier can extend it. An expiry date means the material should not be used after that date. Record which one your lot carries and schedule the re-analysis or replacement before the date arrives.
After the vial is opened
Let a cold vial warm to room temperature before opening it, so humid air does not condense on the powder. Weigh quickly with clean, dry tools, reseal with the desiccant in place and write the opening date on the label. If a lot will be drawn from many times, split it into working vials at the first opening. Never return powder to the original vial. Reconstituted solutions follow the same logic: refrigerate what will be used soon, freeze aliquots for later and do not refreeze a thawed aliquot.
A note on GLP-1 class peptides
Semaglutide, tirzepatide, retatrutide and related peptides are supplied by WYOO to corporate and institutional buyers for research use only. The rules above apply unchanged; these buyers more often specify indicator cards or loggers in their purchase orders.
Commercial terms
WYOO is a sourcing partner with audited partner factories, not a manufacturer. Standard terms are MOQ 50 g, 5 to 10 working days after payment for in-stock lots, T/T 30% deposit and 70% before shipment for B2B accounts, a batch COA with every lot and a free 5 g sample for qualified companies with freight paid by the buyer. Peptides whose TDS calls for cold storage ship in insulated packaging with gel ice packs, with the storage condition printed on the COA. We quote price, MOQ, lead time, Incoterms and documents in one message in English, Chinese, Spanish, German or French within one working day.
Häufige Fragen
- Should lyophilized peptide powder be stored at -20°C or at 2-8°C?
- Follow the storage line on the batch COA or TDS, because it reflects the stability data for that specific peptide. As a general pattern, sealed lyophilized powder that will be held for months goes to -20°C, while working stock that will be used within weeks is often kept at 2-8°C. A few cosmetic-grade peptides are stable at controlled room temperature, but only treat them that way when the document says so.
- The ice packs had melted when my peptide shipment arrived. Is the material still usable?
- In most cases yes. Gel packs are designed to buffer the first part of the journey and are usually thawed after several days in transit, and sealed lyophilized powder tolerates a short period at ambient temperature far better than a solution does. Record the arrival time, the state of the packs and any indicator reading, photograph the package, move the vials to the specified storage at once and send the record to the supplier. Only a tripped indicator, a damaged vial or visible moisture in the powder should trigger a hold.
- What are WYOO's MOQ, lead time, sample and cold-chain packaging terms?
- WYOO is a sourcing partner with audited partner factories. Standard terms are MOQ 50 g, 5 to 10 working days after payment for in-stock lots, T/T 30% deposit and 70% before shipment for B2B accounts, a batch COA with every lot and a free 5 g sample for qualified companies with freight paid by the buyer. Peptides whose TDS calls for cold storage ship in insulated packaging with gel ice packs; indicator cards or loggers can be discussed at the quotation stage. GLP-1 class peptides are supplied to corporate buyers for research use only.