Which three dates matter?
- Expiry date: printed on the pack. The FDA explains that expired medicines can be less effective and, for some products, risky; it advises not to use them.[4]
- Out-of-fridge limit: how long an unopened product may stay at room temperature. The Wegovy® label allows single-dose pens up to 28 days at 8–30 °C before the cap is removed;[2] the Zepbound® label allows single-dose pens and vials up to 21 days in total at up to 30 °C.[1]
- In-use period: how long after first use or mixing. The Zepbound® label says to discard an opened multi-dose vial or KwikPen after 30 days at room temperature, 30 days after first use, or after 4 weekly doses, even if medicine is left.[1] The Ozempic® label gives 56 days for a pen in use.[3]
Which rules do the labels share?
- Fridge at 2–8 °C, away from the cooling element; never freeze, and do not use a product that has been frozen.[1][2]
- Keep in the original carton to protect from light.[1][2]
- Write down the first-use or mixing date — the in-use clock starts there.[1]
- Put used needles in a sharps container; the FDA explains how to dispose of them.[5]
These are examples from specific labels. Your product’s own label and pharmacist are the authority; do not transfer one medicine’s limits to another.
What about reconstituted vials without a label?
Many peptides sold for research have no approved label, so there is no official storage temperature or in-use period after mixing with bacteriostatic water. Any number you see online is not a label. If you were supplied such a vial, ask the prescriber or pharmacist what applies, and record their answer.
What does PepLabo not do?
PepLabo never suggests a storage limit or an in-use period, and it cannot know how your vial was kept. It counts down from the dates and the period you enter.
Wegovy® and Ozempic® are registered trademarks of Novo Nordisk A/S; Zepbound® and Mounjaro® are registered trademarks of Eli Lilly and Company. They are named only to identify the medicines and their labels. PepLabo has no affiliation with these companies.
