What is the thermal exposure on a Shanghai to Canada lane in summer?

Conditions: Shanghai · Canada.

I have read the primary source rather than the summary, which has left me with more questions.

I understand the headline. I do not understand the footnotes, and the footnotes look important.

What would I need in addition before this supported a decision?

Answering this needs the transit duration and the ambient temperature, and then the arithmetic is straightforward.

A single phase-change pack in a thin-walled box holds below ten degrees for roughly one to two days at twenty-five degrees ambient, and under a day at thirty-five. On a nine-to-fourteen-day lane the material is at ambient for most of the journey whatever was packed with it.

The part that matters: a single-use temperature logger costs a few pounds, records the whole journey and converts an argument into a record. If the history matters, this is the answer.

Single-use temperature loggers are standard practice in supply chains where temperature genuinely matters and are inexpensive at parcel scale.

Solutions are a different question and deserve the worry the solids get.

This is where the anxiety in this hobby is most out of proportion to the chemistry.

Once the parcel arrives, the domestic leg is the controllable part: get it into the refrigerator promptly rather than leaving it in a warm hallway for a day.

Concretely, asking a supplier to hold a shipment during a heatwave is reasonable and the better ones agree; the cost is a week and the benefit is a shorter warm exposure for anything in solution.

A liquefied pack is expected. It is not evidence of a problem.

Put another way, if temperature history matters to you, buy a data logger. It is the only way to know.

That is the argument for shipping lyophilised rather than for shipping colder. A dry powder with low residual moisture is stable at ambient for months; the pathways that matter need water.

Solid-state stability of lyophilised peptides at ambient temperature is documented in formulation studies with residual moisture as the dominant variable.

Lyophilised tolerates the lane. That is the answer for almost every order.

The honest answer is that the cold pack is doing much less than people think and that shipping lyophilised is what actually protects the material.

Arrhenius behaviour means the degradation rate roughly doubles per ten degrees. A week at thirty degrees is therefore a meaningful exposure for a solution and an immaterial one for a dry solid.

Nothing here is medical advice, and research-use compounds are not approved for human use.

The domestic leg is the part you control. Refrigerate it promptly.