Do research peptides need to be shipped cold?
Why sealed lyophilised peptides ship fine at ambient temperature, why ice packs can make things worse, and what actually matters in transit.
Suppliers who ship research peptides with ice packs, and suppliers who ship them in a padded envelope, both claim to be doing the right thing. For lyophilised peptides in sealed vials the padded envelope is correct, and the reason is worth understanding, because it also tells you when cold shipping would matter. This note explains what happens to a peptide in transit, why Alphex ships at ambient temperature, and what to check when a parcel arrives. All Alphex products are for laboratory and in-vitro research only.
Powder is not solution
The degradation pathways that shorten a peptide's life (hydrolysis, deamidation, oxidation, aggregation) all need water, or proceed vastly faster in it. A lyophilised peptide with a few percent residual moisture, sealed under vacuum, has almost no water available. Its degradation rate at 20-25 C over a few days is, for the compounds in this catalogue, below what HPLC would detect. Manufacturers' own stability data on freeze-dried peptides routinely show months at room temperature with no measurable change; the recommendation to store at -20 C is about years, not days.
A reconstituted peptide is a different matter. In solution the same peptide can lose measurable purity in days at room temperature. That is why solutions are never shipped, and why the moment you add diluent the clock changes. See how long reconstituted peptides last.
Why ice packs can make things worse
A gel pack in a padded envelope for a two-day UK delivery is warm by the time it arrives, so it has achieved little. Worse, a cold vial arriving into a warm room condenses moisture on the outside of the glass and, if the vial is opened while cold, on the powder inside. Cold shipping of a lyophilised peptide without a proper insulated container and a temperature logger is theatre with a downside. Genuine cold-chain shipping (validated insulated boxes, dry ice or phase-change packs, data loggers) exists, and is used for biologics and solutions that need it; it is not needed for freeze-dried research peptides on a next-day UK service.
What does matter in transit
- Physical protection. Glass vials must not break and stoppers must not be dislodged. Alphex vials ship in a rigid inner box inside a padded outer.
- Vacuum integrity. A vial that loses its seal can take up atmospheric moisture. On arrival, check the stopper is still slightly domed inward and that you feel air rush in on first puncture. If not, contact us before using.
- Light. Vials travel in opaque packaging. GHK-Cu in particular is kept dark.
- Time. Days are fine; weeks in a hot van are not. UK stock and next-day tracked dispatch (same day for orders before 2pm Monday to Friday) mean Alphex parcels are in transit for one to two days. Imported stock relabelled in the UK, or drop-shipped from abroad, can spend a fortnight in uncontrolled conditions and customs sheds. That, rather than a gel pack, is the shipping variable that matters; see why UK stock matters.
What to do when the parcel arrives
- Check the outer for damage and the inner box for broken glass.
- Check each vial: label, batch number, stopper domed inward, cake or film present (a shifted or broken cake is normal).
- Match batch numbers to the COA if you requested it in advance.
- Move vials to -20 C (or 2-8 C for short-term use) in the dark. Do not open until you are ready to reconstitute, and then let them warm to room temperature first.
Frequently asked questions
The parcel sat in a warm sorting office for a day. Is the peptide ruined?
No. A sealed lyophilised vial tolerates that without measurable change. Store it cold on arrival as normal.
Why do some suppliers make a point of cold shipping?
Because it looks like care, and because customers ask for it. For sealed powder it is not a quality signal; a batch-matched COA and UK stock are.
Does Alphex ship internationally?
See international orders. Transit times are longer, and the same logic applies: sealed powder tolerates it, solutions would not.
Alphex research peptides are supplied for laboratory and in-vitro research by qualified researchers only. They are not authorised for human or veterinary use.
Research use only. Alphex products are supplied exclusively for laboratory and in-vitro research by qualified researchers. They are not authorised for human or veterinary use, and nothing in this note is advice on any such use.
Published 3 July 2026. Alphex reviews research notes when the testing method, the catalogue or UK guidance changes.