Read the primary source rather than the write-up and the two do not agree, so here is what is actually in it.
The distinction that matters is unopened versus in use. Unopened vials are stable refrigerated for their labelled shelf life and tolerate a limited excursion to room temperature. Once reconstituted, the clock is much shorter and is set by the preservative rather than by the peptide — bacteriostatic water's benzyl alcohol is what buys you multiple draws over weeks. Sterile water has no preservative and turns a multi-dose vial into a single-use one.
Where I think it is weakest: the comparator does most of the work in how this gets reported, and it is not the comparator most people think they are citing.
What I am trying to establish is what a temperature excursion actually does, and what distinguishes an unopened vial from one already in use. Not looking for reassurance. Looking for the part I have got wrong.
Figures above are from the primary publication rather than the press summary. If a number here disagrees with one you have, post yours and we will work out which of us is reading a secondary source.
PeptideChemSF said:The distinction that matters is unopened versus in use.
Storage question about storage and cold: my pen was left out of the fridge for 8 hours. Is it still good?
Per the manufacturer, both Ozempic and Wegovy pens can be stored at room temp (up to 86°F) for up to 28 days after first use. So yes, it should be fine as long as it wasn't exposed to extreme heat.
PeptideChemSF said:The distinction that matters is unopened versus in use.
I read this differently from PeptideChemSF, on substance rather than tone. Freezing is the one to avoid, and freeze-thaw more so. Ice-crystal formation and the concentration changes at the phase boundary drive aggregation, and aggregated peptide does not recover on thawing. A vial that has been frozen and thawed is not rescued by returning it to the fridge.
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Shop Reference StandardsBariatricNurseD said:Freezing is the one to avoid, and freeze-thaw more so.
Storage best practices for compounded storage and cold:
- Unreconstituted lyophilized powder: refrigerate (36-46°F), good for 12+ months
- Reconstituted vials: refrigerate, use within 28 days
- Pre-filled pens: refrigerate until first use, then room temp OK for 28 days
- Never freeze reconstituted peptides — ice crystals damage the protein
- Protect from light — store in original box or wrap in foil
When in doubt, refrigerate. Temperature abuse is the #1 cause of reduced potency in compounded peptides.