How to store peptides
What FDA labels say about storing peptide drugs like Wegovy and Zepbound, and what that implies for powdered and reconstituted research peptides.
Key takeaways
- Wegovy and Zepbound labels both say: refrigerate at 2–8°C (36–46°F), never freeze, protect from light.
- Wegovy pens may be kept at 8–30°C for up to 28 days before the cap is removed; Zepbound single-dose pens and vials for up to 21 days at up to 30°C.
- Research peptides have no FDA label; their storage guidance comes only from the seller.
Approved peptide drugs come with storage instructions FDA has reviewed. Research peptides do not. Start with what the labels say.
What FDA labels say
| Product | Refrigerated | Room-temperature allowance | Freezing |
|---|---|---|---|
| Wegovy single-dose pen or syringe | 2–8°C (36–46°F) | 8–30°C (46–86°F) for up to 28 days, before cap removal | Do not freeze; do not use if frozen |
| Zepbound single-dose pen or vial | 2–8°C (36–46°F) | Up to 30°C (86°F) for a total of 21 days | Do not freeze; do not use if frozen |
| Zepbound multi-dose vial or KwikPen (unopened) | 2–8°C until expiry | Discard after 30 days at room temperature | Do not freeze |
Both labels also say to protect the product from light and keep it in the original carton.
Research peptides
Lyophilized powder is generally more stable than a solution, which is why most research peptides ship that way. Once reconstituted with bacteriostatic water, the solution’s shelf life depends on the peptide, the diluent and handling — and sellers rarely publish stability data. Treat any seller’s storage claim as unverified unless it cites a study.
Related
- How to reconstitute peptides
- Semaglutide and tirzepatide profiles
- Glossary
What the evidence does not show
- Stability data for any specific research-peptide product — sellers rarely publish it.
Frequently asked questions
Do peptides need to be refrigerated?
FDA-approved injectable peptides such as Wegovy and Zepbound are labeled for refrigeration at 2–8°C, with limited room-temperature allowances. For research peptides, follow the seller's instructions and ask for stability data.
Can you freeze peptides?
The Wegovy and Zepbound labels both say not to freeze and not to use a product that has been frozen. Some sellers recommend freezing lyophilized powder for long-term storage; that guidance is not FDA-reviewed.
How long does Zepbound last out of the fridge?
Single-dose pens and vials: up to 21 days in total at up to 30°C (86°F). Unopened multi-dose vials or KwikPens kept at room temperature must be discarded after 30 days.
Sources
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