Definition: The cold chain is the unbroken run of correct cold storage a temperature-sensitive medicine needs, from the maker through shipping, the pharmacy and your fridge. One break, such as a box left in the sun or a pen that froze, can make it unfit to use. The Wegovy and Mounjaro labels say not to use a pen that has been frozen.
The Wegovy label says to store pens in the refrigerator at 2-8°C (36-46°F), not to freeze them, and not to use a pen that has been frozen. Unused single-dose pens may be kept at 8-30°C (46-86°F) in the carton for up to 28 days. Mounjaro single-dose pens are stored at 2-8°C and may be kept unrefrigerated for up to 21 days total, not above 30°C (86°F).
Not everything needs cold. The Depo-Testosterone label says to store it at room temperature, 20-25°C (68-77°F), protected from light. Cold chain applies to the products whose labels call for it.
For vaccines, CDC says not to use doses stored outside recommended temperatures unless safety and effectiveness are confirmed. GLP-1 labels follow the same logic: a frozen pen is not to be used.
Counting days out of the fridge
Room-temperature allowances add up across trips, so a running total is easier than memory. If a dose seems to work less well, a note about a warm delivery or a frozen fridge shelf gives you and your prescriber something concrete to check.
Compounded and research products have no tested label limits, so there is no published number to count against.
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