Accepted answer
Start with the physical state. Lyophilised powder is stable at ambient for the duration of any normal lane; anything in solution is a different conversation entirely.
Summer lanes are worse than winter lanes for the pack and no different for the solid, which is why the seasonal anxiety is largely misdirected.
Reported transit ranges with tracking
| Lane | Reported range | Median | Where the variance comes from |
|---|
| Coastal China → western Europe | 8–14 days | 11 days | Customs queue at the destination hub |
| Inland China → western Europe | 10–16 days | 13 days | Domestic leg to the international gateway |
| China → United Kingdom | 8–13 days | 10 days | Single clearance point, usually quick |
| China → United States, west | 8–16 days | 12 days | Onward domestic carrier |
| China → Australia | 10–20 days | 15 days | Fewer direct services; inspection rate |
| Regional warehouse → same region | 2–5 days | 3 days | No clearance step at all |
These are ranges members have reported, not quotes. Judge a lane on whether tracking scans continuously rather than on days elapsed.
A single-use temperature data logger costs a few pounds and converts speculation into a record. If the temperature history matters to you, buy one rather than arguing about packaging.
Phase-change pack hold times are a function of mass, latent heat and box insulation, and published figures for small parcels are on the order of a day or two.
Nothing here is medical advice, and research-use compounds are not approved for human use.
A liquefied pack on arrival is expected. It is not evidence of a problem.