Accepted answer
Answering this needs the origin and destination pair, because lane behaviour varies far more than carrier marketing suggests.
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.
Anything shipped in solution is a genuinely different risk, because hydrolysis and deamidation proceed in the aqueous phase and are strongly temperature-dependent.
Single-use temperature loggers are inexpensive and are standard practice in any supply chain where temperature actually matters.
Nothing here is medical advice, and research-use compounds are not approved for human use.
Judge the lane by tracking continuity rather than by days elapsed.