How long does tirzepatide last after reconstitution?

In its lyophilized (freeze-dried) form, tirzepatide powder is highly stable. The dehydrated state removes the aqueous environment that drives hydrolysis and oxidation - the two primary degradation pathways for peptides.

Lyophilized tirzepatide can be stored at room temperature (below 25°C / 77°F) for up to 12 months from the manufacture date without significant potency loss, provided it is kept away from moisture, heat, and direct light. Refrigerating the dry powder at 2–8°C extends this stability window further - often to 18–24 months in ideal conditions. The powder can also be frozen at −20°C for long-term archival storage.

Keep the vial sealed and desiccated until you are ready to use it. Humidity is the primary enemy of lyophilized peptides. If the vial has been opened or the vacuum seal appears compromised (rubber stopper does not spring back, powder appears clumped or discolored), do not use it.

Once bacteriostatic water is added to the vial, the stability window drops significantly. The benzyl alcohol in bacteriostatic water inhibits microbial growth but does not halt chemical degradation of the peptide backbone.

At 2–8°C, reconstituted tirzepatide is considered stable for up to 28 days. Beyond this window, potency loss accelerates even under ideal refrigeration. Some researchers report extended stability past 28 days, but no peer-reviewed data currently supports using reconstituted tirzepatide beyond one month.

Avoid repeated warming and cooling cycles. Each time the vial warms to room temperature for administration and returns to the refrigerator, cumulative thermal stress contributes to degradation. Remove only the volume needed per dose and return the vial to cold storage immediately.