Storing and Travelling with Mounjaro

Mounjaro (tirzepatide) KwikPens should be stored in the fridge at 2°C to 8°C, kept in their carton to protect them from light, and never frozen. The UK patient leaflet also allows a pen to be kept unrefrigerated, at no more than 30°C, for up to 30 days, after which it must be thrown away. That flexibility makes travel much easier, but heat, freezing and long journeys still need planning. This guide explains the official storage rules, what to do if something goes wrong, and how to travel in the UK and abroad with your medicine.

The official storage rules

The UK rules for storing Mounjaro come from its Patient Information Leaflet (PIL) and Summary of Product Characteristics (SmPC), both published on the Electronic Medicines Compendium. The details below reflect the leaflet at the time of writing. Always check the leaflet that comes in your pack, because product information is updated from time to time and packs can differ.

Why temperature matters

Tirzepatide is a peptide, a chain of amino acids similar in structure to a small protein. Peptides can be damaged by freezing and by high temperatures. A damaged medicine may look normal but work less well, or not at all. Because you cannot tell by looking whether the medicine has been affected, following the storage rules matters more than checking the appearance.

That said, it is still sensible to check the solution before each injection. The leaflet describes the solution as clear and colourless to slightly yellow. Do not use it if it is cloudy, discoloured or contains particles.

The KwikPen and its four doses

In the UK, Mounjaro is supplied as a KwikPen, a multi-dose pre-filled pen containing four weekly doses of a single strength. You attach a new pen needle for each injection. Because one pen lasts about a month, the 30-day unrefrigerated allowance can cover a full pen if you prefer to keep it at room temperature once you have started it.

Our step-by-step KwikPen guide covers how to prime the pen, inject and remove the needle safely. For an overview of the medicine and its licence, see the Mounjaro hub.

Storing Mounjaro at home

In the fridge

• Keep pens in the main body of the fridge, not in the door, where temperatures swing more each time it opens, and not near the back wall or cooling element, where items can freeze.
• Keep them in the carton. This protects against light and keeps the pharmacy label with the pen.
• Consider a fridge thermometer. Domestic fridges vary, and some run colder than their setting suggests, particularly at the back or bottom.
• Keep out of the sight and reach of children.
• Do not store pens next to the freezer compartment in fridges with a small internal ice box.

Out of the fridge

If you choose to use the 30-day room-temperature allowance:

• Write the date you took the pen out of the fridge on the carton, so you know when 30 days is up.
• Keep it somewhere that stays below 30°C. Avoid windowsills, radiators, cars, conservatories and steamy bathrooms.
• Keep it in the carton, out of direct sunlight.
• Discard after 30 days, even if there is medicine left.

Once a pen has been kept at room temperature, it should not be treated as though it had been in the fridge the whole time. Follow the leaflet's limit.

Before and after an injection

It can be more comfortable to let the pen reach room temperature before injecting, but you do not need to. Follow the instructions for use in your pack. After injecting, remove and dispose of the needle, replace the pen cap and return the pen to storage. Do not store the pen with a needle attached, because this can let air in or medicine leak out.

What to do if something goes wrong

The pen has frozen

Do not use a Mounjaro pen that has been frozen, even if it has thawed and looks normal. Contact your pharmacy or provider for advice. They can tell you how to arrange a replacement and how to handle your next dose. Keep any receipts or details if a fridge fault was responsible, in case your home insurance covers spoiled medicines.

The pen has been too warm

If a pen has been above 30°C, for example left in a hot car or in direct sun, or has been out of the fridge for longer than 30 days, it may no longer work properly. Do not use it without checking first. Your pharmacist can advise, and some may contact the manufacturer for specific guidance. Eli Lilly also runs a UK medical information service that answers product questions.

The fridge has failed

If your fridge has been off for a few hours, the pens may still be within the room-temperature allowance, as long as they have not been above 30°C. Count the time out of refrigeration towards the 30-day limit and ask a pharmacist if you are unsure.

You have run out or a pen is damaged

If a pen is cracked, leaking or broken, do not use it. Contact the pharmacy that supplied it. If you are about to run out, contact your prescriber or provider in good time. Our guide to missed Mounjaro doses explains what the SmPC says about doses that are delayed or missed, which may help if supply is interrupted.

Travelling with Mounjaro

Planning before you go

Good planning prevents most problems:

1. Check you have enough pens for your trip, plus a margin for delays. Speak to your prescriber or provider early if you need an extra supply, and be aware that they will need to judge whether that is appropriate.
2. Check the timing of your dose increases. It may be easier to avoid stepping up to a new dose just before or during a trip, because side effects can be stronger after an increase. Discuss this with your prescriber rather than changing the plan yourself.
3. Bring enough pen needles, plus spares, and a portable sharps container.
4. Pack documentation: the pharmacy-labelled carton and a copy of your prescription, or a letter from your prescriber confirming that you use tirzepatide injections.
5. Check the rules at your destination. Some countries have specific requirements for bringing prescription medicines in. The embassy or consulate of the country you are visiting can confirm what is needed.
6. Check travel insurance. Make sure you have declared relevant medical conditions and that cover includes medicines.

Cool bags and insulated cases

For many trips, the 30-day room-temperature allowance means a pen can travel without refrigeration, as long as it stays below 30°C. For journeys in hot weather, or if you are carrying pens you want to keep refrigerated, an insulated medicine travel case can help.

Points to keep in mind:

• Do not let pens touch ice packs directly. Direct contact can freeze the medicine. Wrap the pen or use a case with a barrier.
• Gel and ice packs may be subject to airport liquid rules. Check with your airport or airline before you fly.
• Electronic and evaporative cooling cases are available; check that they keep within the 2°C to 8°C range if you intend to keep the pen refrigerated.

Flying

UK government guidance on hand luggage allows essential medicines to be carried through security, including in containers larger than the usual liquid limit, when you have supporting documentation such as a prescription or a letter from a medical professional. Rules can differ between airports and change over time, so check the current guidance on GOV.UK and with your airline before you travel.

Practical tips:

• Always carry pens in your hand luggage. The cargo hold can get extremely cold, and checked bags can be lost or delayed.
• Keep pens in the original carton with the pharmacy label showing your name.
• Tell security staff that you are carrying injectable medicine and needles if asked, and have your documents ready.
• Keep pens out of direct sunlight at your seat and away from heat sources.
• Avoid storing pens in hotel minibars unless you are confident about the temperature. Some run very cold, others are not cold at all. Ask the hotel for a proper fridge if needed, and check it is not freezing items.

Long-haul trips and time zones

Because Mounjaro is taken once a week, time zones are less of an issue than with daily medicines. The UK SmPC states that the day of the weekly injection can be changed if necessary, as long as the time between two doses is at least three days (72 hours). Once you have chosen a new day, continue with weekly doses on that day.

For a long-haul trip, a simple approach is to keep injecting on your usual day, at a convenient local time. If a trip disrupts your schedule significantly, plan with your prescriber or pharmacist beforehand. If you do miss a dose, the SmPC says to take it as soon as possible within four days of the missed dose; if more than four days have passed, skip it and take the next dose on your usual day.

Hot countries

In hot climates, room temperature may exceed 30°C, which is above the leaflet's limit for unrefrigerated storage. In this situation:

• Keep pens in a fridge at your accommodation, checking they will not freeze.
• Use an insulated case when you are out.
• Never leave pens in a car, on a beach or in direct sun.
• If a pen may have overheated, seek advice before using it.

Road and rail trips in the UK

Cars can heat up quickly, even on a mild sunny day, and the boot can be hotter still. Keep pens in the passenger area, out of direct sunlight, ideally in an insulated case. On long journeys, avoid leaving them in a parked car.

Other situations

At work or staying with others

If you inject at a time when you are away from home, you can usually rely on the 30-day room-temperature allowance rather than needing a workplace fridge. If you do use a shared fridge, keep the pen in a labelled bag or container, away from the back wall, and out of reach of others. Take the pen home with you rather than leaving it somewhere you cannot monitor the temperature.

Camping, festivals and outdoor trips

Tents, caravans and cars can become very hot during the day and cold at night. If you are away for a short trip, it may be simpler to time your injection so that you do not need to bring a pen at all, as long as you stay within the rules on dose timing. If you need to bring a pen, an insulated case kept in the shade is important, and the pen should never be left in a hot vehicle or exposed to frost.

Cruises

Cabins on cruise ships usually have a small fridge, but its temperature may not be reliable. Ask the ship's medical centre whether they can store medicines, and check that the fridge in your cabin does not freeze items. Bring documentation, as you would for a flight, because you may pass through several countries.

Moving house or a long stay away

If you are moving or spending several months away from home, plan your supply and follow-up with your prescriber in advance. Prescribers need to review treatment regularly, including weight and side effects, and some will not supply large quantities at once. If you are moving abroad for a longer period, you will usually need to arrange care with a prescriber in that country.

A quick storage checklist

• Fridge at 2°C to 8°C, pen in the carton, away from the cooling element.
• Never frozen. If it has been, do not use it.
• Out of the fridge: no more than 30°C, for no more than 30 days. Date the carton.
• New needle for every injection; never store the pen with a needle attached.
• Check the solution is clear and colourless to slightly yellow before injecting.
• Hand luggage only when flying, with the pharmacy label and a prescription or letter.
• Used needles in a sharps bin; old pens back to the pharmacy.

Side effects while travelling

Travel can bring its own challenges for people taking GLP-1 medicines. Smaller meals, richer food, alcohol, heat and long journeys can all make side effects such as nausea, constipation and dehydration more noticeable.

• Stay well hydrated, particularly in hot climates and on flights. See our guide to hydration on GLP-1 medication.
• Be cautious with alcohol, which can worsen nausea and dehydration. Our guide to Mounjaro and alcohol explains why.
• Pack simple remedies you know work for you, after checking with a pharmacist that they are suitable alongside your other medicines.
• Take care with food and water hygiene abroad. A stomach bug on top of GLP-1 side effects can lead to dehydration faster.
• Know how to get help at your destination, and carry details of your medicines and medical conditions.

If you are taking oral contraception, remember that the Mounjaro leaflet advises considering a barrier or non-oral method for four weeks after starting and after each dose increase. Vomiting or diarrhoea while travelling can also affect how well the pill works.

Do not source Mounjaro abroad or from unregulated sellers

Running short while away can be stressful, but obtaining tirzepatide from overseas pharmacies, social media sellers or unregulated websites carries serious risks. The MHRA has repeatedly warned about falsified and unlicensed weight-loss injections, including products sold as "tirzepatide" that contain the wrong dose, different substances or contaminants.

In the UK, Mounjaro should be supplied only on a prescription from a regulated prescriber and dispensed by a registered pharmacy. If you need help with supply while travelling, contact your prescriber or the pharmacy that supplied your medicine. Our guides to fake and unlicensed weight-loss jabs and getting weight-loss injections online safely explain how to check a provider is legitimate.

If you are reviewing which regulated services you use, our provider comparison sets out how services differ on prescribing, delivery and support. Delivery arrangements, including whether medicines are sent in temperature-controlled packaging, are one of the factors that can affect overall cost; see our prices page for more.

Receiving Mounjaro by post

Many people in the UK receive their pens by post from an online pharmacy. Regulated pharmacies usually send injectable medicines in insulated packaging with cool packs, designed to keep the medicine within range for a set period.

When your parcel arrives:

• Open it promptly and put the pens in the fridge.
• Check the packaging for damage and the pens for any signs of freezing or leakage.
• Check the label: correct name, medicine and strength.
• Contact the pharmacy if the parcel was delayed, arrived warm, or the contents look damaged. Do not use pens you are unsure about.

If you will not be home, arrange a safe delivery option or a collection point, so the parcel does not sit in a hot porch or van for longer than necessary.

Disposing of pens and needles safely

• Needles: put used pen needles straight into a sharps bin. Your pharmacy or local council can advise on how to get a sharps bin and how to dispose of it once full; arrangements vary by area.
• Pens: return empty, expired or unused pens to a pharmacy rather than putting them in household waste or flushing them away.
• When travelling: use a portable sharps container and bring it home, or follow local rules.

Never share pens, even with a new needle. Sharing can spread infections.

When to speak to a professional

Contact your pharmacist, prescriber or provider if:

• A pen has frozen, overheated, or been out of the fridge longer than the leaflet allows.
• A pen is damaged, leaking or looks cloudy or discoloured.
• Your delivery arrived warm or delayed.
• You need advice about taking enough supply for a trip, or changing your dose schedule around travel.
• You are unsure about the rules for taking medicines into another country.

Seek urgent medical help (NHS 111, or 999 / A&E in an emergency, or the local emergency number abroad) if, while taking Mounjaro, you develop:

• Severe, persistent abdominal pain, which may spread to your back, with or without vomiting. This can be a sign of pancreatitis.
• Signs of significant dehydration, such as dizziness, confusion, a very dry mouth or passing very little urine, especially if you cannot keep fluids down.
• Signs of a serious allergic reaction, such as swelling of the face, lips or throat, or difficulty breathing.

Your prescriber and pharmacist are there to help with practical questions about supply, storage and schedules, as well as medical ones.