This is a recurring problem with one particular shipping lane rather than a one-off.
I want to decide this in advance so that I am not deciding it under pressure later.
Assume I will follow the plan I write down, so I would like it to be a good one.
What should I decide now, and what should I defer?
Start with the physical state, because lyophilised and reconstituted material have completely different storage answers.
Let a refrigerated or frozen vial equilibrate to room temperature before opening, so humid air does not condense water onto a cold cake.
| State | Condition | Usable window | Basis |
|---|---|---|---|
| Lyophilised solid | −20 °C, sealed, dry | 24–36 months | Supplier guidance |
| Lyophilised solid | 2–8 °C, sealed | 12–24 months | Supplier guidance |
| Lyophilised solid | 25 °C, sealed | 4–8 weeks | Extrapolated (Arrhenius) |
| Lyophilised solid | 40 °C, sealed | 1–2 weeks | Extrapolated |
| Solution, preserved | 2–8 °C | 28 days | USP microbiological convention |
| Solution, preserved | 25 °C | 3–7 days | Extrapolated |
| Solution, unpreserved | 2–8 °C | 24 hours | USP microbiological convention |
Windows for the solid state are chemical; windows for solution are microbiological and usually shorter than the chemical limit.
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.
Residual moisture is the dominant determinant of solid-state stability, which is why desiccants accompany lyophilised material.
A printed expiry on research-grade material has no stability programme behind it.
Keep the desiccant with the vial and the certificate with the lot code.
Analytical standards and reagents with traceable certificates. Every quantitative result you read inherits the accuracy of the standard behind it.
Shop standardsAnswer first: dry, cold, dark and still, with the lot code where you can still read it in a year.
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.
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.
Photodegradation of tryptophan-containing peptides is documented and is the basis for light-protected storage recommendations.
Label the vial at reconstitution with date, concentration and units per dose.
edited 18 Aug 2026 by m_haraldsen — fixed an arithmetic slip in the third paragraph
Answering this needs the intended duration, since a fortnight and two years call for different arrangements.
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.
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.
Dry, cold, dark, still. Four words and you have the answer.
Keep the paperwork with the material, or the material becomes anonymous.
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.
Appearance does not indicate stability; a normal-looking cake can be substantially degraded.
Minus eighty buys very little over minus twenty for a dry solid.
This is the tag where the advice is cheapest to follow and most often ignored.
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.
The 28-day in-use period for preservative-containing multi-dose preparations is printed on the diluent labelling and is a long-standing pharmacy convention.
Nothing here is medical advice, and research-use compounds are not approved for human use.
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.