Travelling internationally on Mounjaro or Wegovy: cold chain, customs, time zones

What the SmPC actually says about storage

The two products have similar but not identical rules. Mounjaro (tirzepatide) KwikPen and pre-filled pens must be stored in a refrigerator at 2 to 8 degrees Celsius until first use. After first use — or if removed from the fridge — they can be kept at temperatures up to 30 degrees Celsius for up to 30 days, after which any unused product should be discarded. The pen must be protected from light and not frozen.

Wegovy (semaglutide) is similar: fridge at 2 to 8 degrees until first use, then up to 28 days at temperatures not exceeding 30 degrees. Both should not be exposed to direct sunlight or left in a hot car.

The key practical point is the 30-degree ceiling. Most British holiday destinations in summer exceed that easily — Spain, Greece, the UAE, Saudi Arabia, Florida and most of Southeast Asia all run above 30 by mid-afternoon. You cannot simply leave the pen on a hotel bedside table in 35-degree heat and expect it to work. This isn't a minor consideration: tirzepatide and semaglutide are peptides and degrade with heat.

Cool bag strategy for flights

For a single flight up to about 14 hours, a small insulated medical cool bag with two or three gel packs (refrigerated overnight before you leave) keeps the pen below 8 degrees comfortably. Brand names like Frio, MedActiv and Vivi Cap are well tested. Avoid: dry ice (banned in cabin baggage by most airlines and IATA rules), and avoid putting the pen in the hold (the temperature in unpressurised cargo holds can drop well below freezing — and frozen GLP-1 is destroyed).

For longer trips, your hotel mini-bar fridge is your friend. Almost every European, US, Middle Eastern and Asian hotel has one. Check ahead with the hotel that the mini-bar isn't disabled or set to a non-refrigeration mode — some boutique hotels do this. If you're staying somewhere without a fridge (a riad, a homestay, a Hajj tent in Mina), you'll need a more serious solution: a battery-powered medical cooler such as the Roactive or Med Angel.

Airport security: what to expect

GLP-1 pens are unfamiliar to most security screeners. A few practical points:

• Carry-on, not hold luggage. Always. Hold temperatures are unsafe and lost luggage means missed doses.
• Doctor or pharmacist letter. We provide a short signed letter on Empire Pharmacy letterhead confirming the medication, the prescription, and the medical need to keep gel packs cold. This satisfies TSA, UK airport security, and most international equivalents. Email us at least 48 hours before travel and we'll send a PDF.
• Keep pens in the original carton. Loose pens trigger questions; original packaging with the pharmacy label answers them immediately.
• Gel packs: partially or fully frozen gel packs are sometimes flagged as liquids over 100ml. In practice, the medical exemption almost always covers them — but having the letter saves an argument.

Customs declarations: Middle East and Asia

This is the area travellers most often get caught out. Several countries treat injectable medications as controlled goods and require either declaration on arrival or, in extreme cases, a pre-import permit.

• UAE: Mounjaro and Wegovy are approved and widely available, but you should still carry your prescription and the pharmacy label. Single-traveller personal-use quantities (up to three months) are usually fine.
• Saudi Arabia: Similar to UAE — bring your prescription. Hajj pilgrims should declare any injectable medication if asked.
• Japan: Strict on injectable medications. Yakkan Shoumei (medication import certificate) is required for stays longer than one month or for quantities above the personal-use limit. For a one-week trip with one pen, you're fine; for a month with multiple pens, apply ahead.
• Singapore and Thailand: Bring prescription and pharmacy label; personal-use quantities are accepted.
• United States: No customs issue for personal use with a prescription.

If your destination isn't on this list, check the embassy website before you fly. The IAMAT (International Association for Medical Assistance to Travellers) website has a reliable country-by-country medication import guide.

Time zones: when to inject

Both Mounjaro and Wegovy are weekly injections, and both SmPCs allow flexibility — you can shift the day if needed, as long as the gap between injections is at least three days (Mounjaro) or 72 hours (Wegovy).

The practical approach: for short trips (under a week) crossing a few time zones, just continue on your usual day at your usual local time. The biology doesn't care about a few hours either way. For longer trips (over two weeks) with a big time-zone shift, you can gradually move your injection day by a few hours each week, or simply pick a new fixed time once you've arrived and use that. For a 12-hour shift (UK to East Asia or Hawaii), most patients move it once permanently rather than try to track UK time.

If you've just started a higher dose and your titration schedule is in week-by-week increments, don't make changes mid-trip. Stay on your current dose for the duration and increase when you're back home, where we can support you if side effects worsen.

Missed dose in transit

Both SmPCs cover this. For Mounjaro: if the missed dose is within four days of the scheduled time, take it as soon as you remember. If more than four days have passed, skip and resume on your next scheduled day. For Wegovy: if within five days, take it; if more than five days, skip. Never double-dose to catch up.

Pre-trip checklist

• Enough pens for the trip plus one spare
• Refrigerated gel packs (two minimum) and insulated cool bag
• Spare needles if your pen takes external needles (Wegovy single-use cartridges are built in; Mounjaro KwikPen also has built-in needles)
• Sharps disposal container (small travel size) or a hard plastic bottle as backup
• Pharmacy letter from Empire Pharmacy (email us 48 hours ahead)
• Photograph of your prescription on your phone
• Hotel confirmation that mini-bar fridge is functional
• Travel insurance that covers pre-existing conditions and medication

If something goes wrong

If your pen overheats (left in a hot car, hotel fridge fails), the manufacturer's advice is to discard. The peptide will have degraded and you can't reliably know how much. Don't inject heat-damaged product — it might be ineffective or, less commonly, more painful. Contact us at Trafford Clinic Manchester from abroad and we can either issue a replacement prescription to a local UK pharmacy for collection by a family member or, in some destinations, signpost you to an in-country supplier.

If you experience severe nausea, abdominal pain or vomiting on a trip, see a local doctor and contact us when you're able. See our guides on GLP-1 side effects timeline and Mounjaro vs Wegovy for what's normal and what isn't.

Booking a pre-trip consultation

We routinely run pre-trip check-ins for our weight-management patients ahead of major holidays, Hajj, or work travel. The appointment covers the cool-chain plan, prescription letter, dose schedule for the trip, and any titration adjustment. Book at traffordclinic.co.uk/weight-loss or call 0161 258 6149.

Our weight-loss clinic operates from Old Trafford with patients across Greater Manchester — including Salford Quays, Altrincham, and the wider Manchester area. Empire Pharmacy is GPhC-registered (premises 1123966) and our lead pharmacist Haroon Iqbal is an Independent Prescriber (reg. 2051093).