Accepted answer
2–8 °C is inside or near the refrigerated band. 2–8 °C is the condition the rule of thumb is anchored to, so it is the baseline rather than a multiplier: everything else in this thread is quoted relative to it. That is the condition most lyophilised peptide is specified at, so the useful question moves to what happens after reconstitution, where the same temperature buys far less. 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.
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.
Reported and extrapolated stability by condition
| 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.
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.
Keep the desiccant with the vial and the certificate with the lot code.
edited 27 Apr 2025 by ekaterina_volk — updated for the 2026 guidance change
Adding for future readers: the domestic leg after delivery is the part you control. – a_lindgren 2 months ago Does the same reasoning apply to material already in solution, or is that a different curve? – Dr_Priya_Raghunathan 3 months ago add a comment