The specifics, since they change the answer: Qingdao · Singapore.
I can parse the result. I am less sure what it licenses me to conclude.
I have deliberately not looked at anyone else’s interpretation yet.
Which parts of this are informative and which are decoration?
Answer first: for a lyophilised solid the cold chain matters far less than people believe, and for a solution it matters far more than they act as though it does.
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.
Stated carefully, 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.
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.
Aggregated, published test results and vendor ratings built from submitted batches. Methodology stated, dataset browsable, no listing fees.
Browse resultsThe relevant physics is latent heat: a phase-change pack holds temperature only while it is changing phase, and once it has melted it is a warm mass.
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.
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.
Arrhenius kinetics predict approximately a doubling of degradation rate per ten-degree rise and are the standard basis for cold-chain design.
A liquefied pack is expected. It is not evidence of a problem.
The short version: a spent cold pack on arrival is expected, the solid does not mind, and the pack was never going to last twelve days.
Anything shipped in solution is a different risk category, because hydrolysis and deamidation proceed in the aqueous phase and are strongly temperature-dependent.
On the detail: 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.
A cold pack tells you nothing about the eleven days before the last one.
Buy a logger if you actually want to know. Everything else is inference.
edited 17 Jul 2025 by greta_holzmann — added the placebo-arm figures
In practice, the domestic leg after arrival is the part most often left in a warm hallway and least often worried about.
A pack that arrived hard tells you about the last day of transit only, since it will have melted and, if the ambient dropped, partially refrozen.
Phase-change pack hold time is a function of mass, latent heat and insulation, and published figures for small parcels are on the order of one to two days.
The domestic leg is the part you control. Refrigerate it promptly.
Start with the physical state, because it changes the answer completely and is the first thing to establish.
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.
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.
Ask PeptideStack is a static archive. Posting is closed, but the norms are worth stating: answer the question that was asked, show your working, cite the trial or the certificate, and say plainly where the evidence runs out.