Do peptides need to be refrigerated?
Most injectable peptides should be refrigerated and never frozen. Some pens can stay at room temperature for a limited time, so follow the label.
Medically reviewed by Charles Kamen, MD, board-certified neurologist ·
The short answer
Most injectable peptides need to be refrigerated, usually between 36°F and 46°F (2°C to 8°C), and should never be frozen. The FDA labels for the weight-loss pens build in some flexibility. A Wegovy single-dose pen can be kept between 46°F and 86°F for up to 28 days before the cap is removed, and Zepbound single-dose pens and vials can be stored unrefrigerated, up to 86°F, for up to 21 days. Multi-dose pens have their own, longer windows once in use. Semaglutide tablets are a different case: Rybelsus is stored at room temperature in its original bottle. For compounded peptides, the dispensing pharmacy’s label is the rule, because it sets the storage temperature and the beyond-use date for that preparation. Heat, freezing and light can damage peptides, so a mishandled product may not work as intended.
Storing a compounded peptide
Compounded peptides often arrive as a freeze-dried powder that is mixed with a sterile liquid before use. Storage before and after mixing can differ, and the beyond-use date, the last day the preparation should be used, is set by the pharmacy under sterile-compounding standards. Write the mixing date on the vial and discard it on the date the label gives, even if some remains.
Do not rely on storage instructions from a forum or a seller’s website. Products sold as "research use only" come with no verified storage, purity or dating information at all, which is one more reason to avoid them. Our page on research-use-only peptides explains the risks.
Traveling with peptides
TSA allows medically necessary liquids, including injectable medicines, in carry-on bags in reasonable quantities above the usual 3.4-ounce limit, as long as you declare them at the checkpoint. Cold packs that keep medicine cool are allowed frozen or partly melted, and unused syringes are allowed when they travel with injectable medication. Keep them in your carry-on, since checked bags can get too hot or too cold.
On longer trips, an insulated case with a cold pack keeps pens in range. Many pen labels also allow some time at room temperature, so check yours before you go, and carry the pharmacy label in case anyone asks.
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Clear instructions with every prescription
Patients of Dr. Kamen get prescriptions filled by licensed pharmacies, with storage and dating on the label. Visits are in person in Las Vegas, or by telehealth when you are in Nevada.
Related questions
How long can peptides be left out of the fridge?
It depends on the product. A Wegovy single-dose pen can stay at 46°F to 86°F for up to 28 days before the cap is removed, and Zepbound single-dose pens and vials can be unrefrigerated for up to 21 days. Multi-dose pens allow longer once in use: up to 56 days for the Wegovy FlexTouch pen and 30 days for the Zepbound KwikPen. For compounded peptides, follow the pharmacy label. If a medicine has frozen or sat somewhere hot, ask your pharmacist before using it.
Do peptides expire?
Yes. Manufactured pens and tablets carry an expiration date, and compounded preparations carry a beyond-use date set by the pharmacy. Once a powder is mixed, the label often allows a much shorter window. Do not use a peptide past its date.
Can you take peptides on a plane?
Prescribed peptide medicines, yes, in your carry-on. TSA allows medically necessary liquids and injectable medicines in reasonable quantities above the usual 3.4-ounce limit, along with cold packs that keep them cool, as long as you declare them at screening. Keep them out of checked luggage, where temperatures can swing. If you are flying abroad, check the destination country’s rules for bringing in medicines.
Sources
Checked October 30, 2026. Labels, guidelines and coverage rules change, so confirm anything that affects your care with your clinician or pharmacist.
- DailyMed - WEGOVY (semaglutide) injection and tablets prescribing information.
- DailyMed - ZEPBOUND (tirzepatide) prescribing information.
- DailyMed - RYBELSUS (semaglutide) tablets prescribing information.
- USP General Chapter <797> Pharmaceutical Compounding: Sterile Preparations.
- TSA: Liquid medications.
- TSA: Disabilities and medical conditions (medication and cold packs at screening).
- TSA: Unused syringes.
Educational information from LiveNow Longevity, not medical advice. It gives no doses and does not replace an evaluation by a licensed clinician who knows your history.
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