The case in front of me: 25 °C · oral semaglutide.
I want to know whether there is evidence behind this or only repetition.
I have checked the obvious registries and monographs without success.
Has anyone verified this independently?
25 °C is above the refrigerated band, and how far above is the whole answer. 25 °C is 20 kelvin above the 5 °C middle of a 2–8 °C refrigerator. The ten-degree rule of thumb — degradation rate roughly doubling per 10 K — makes that about 4 times the refrigerated rate, which is an order-of-magnitude statement and not a shelf life. Lyophilised material tolerates this far better than solution does, which is why it is shipped that way, but "tolerates" is a statement about weeks and the vial is being asked about months. Log the excursion rather than guess at it. Nothing here is medical advice, and research-use-only material is not approved for human use.
Start with the physical state, because lyophilised and reconstituted material have completely different storage answers.
Keep vials in their original carton or in an opaque box. Light exposure matters for tryptophan-containing sequences and for anything with a chromophore, and a closed box is free.
Store with the desiccant sachet if one was supplied, inside the secondary container rather than loose in a drawer. Residual moisture is the dominant variable in solid-state stability.
Residual moisture is the dominant determinant of solid-state stability, which is why desiccants accompany lyophilised material.
Label the vial at reconstitution with date, concentration and units per dose.
Aggregated, published test results and vendor ratings built from submitted batches. Methodology stated, dataset browsable, no listing fees.
Browse resultsAnswering this needs the intended duration, since a fortnight and two years call for different arrangements.
Position matters less than people think: upright or on its side makes no difference to a lyophilised powder, and upright is marginally better for a reconstituted vial because it keeps the stopper dry.
Label the vial at reconstitution with the date, the concentration and the resulting units per dose. This is the single most useful thirty seconds in the whole process.
Dry, cold, dark, still. Four words and you have the answer.
edited 11 Apr 2025 by klara_novotna — added the placebo-arm figures
Answer first: dry, cold, dark and still, with the lot code where you can still read it in a year.
Reconstituted with a preservative-containing diluent: refrigerated, conventionally treated as usable for about 28 days from first entry. Without a preservative, single use and discard.
Put another way, let a refrigerated or frozen vial equilibrate to room temperature before opening, so humid air does not condense water onto a cold cake.
Photodegradation of tryptophan-containing peptides is documented and is the basis for light-protected storage recommendations.
Keep the desiccant with the vial and the certificate with the lot code.
This is the tag where the advice is cheapest to follow and most often ignored.
Keep the certificate with the vial, physically or as a photograph filed under the lot code. A vial without a traceable certificate is an anonymous vial regardless of where it came from.
Two-to-eight-degree refrigeration and minus-twenty freezing are the standard storage conditions for lyophilised peptides in supplier documentation across the market.
Nothing here is medical advice, and research-use compounds are not approved for human use.
Minus eighty buys very little over minus twenty for a dry solid.
In practice, the relevant practical failure is not chemical at all: it is losing the link between a vial and its certificate when the box gets thrown away.
Lyophilised powder: refrigerated at two to eight degrees for months, frozen at minus twenty for longer. The gain from minus eighty over minus twenty is small for a dry solid and is not usually worth the arrangement.
Equilibrate before opening or you condense water into the cake.
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.