How to Store Wegovy, Ozempic and Mounjaro: Temperature, Travel and Pens

Storing your GLP-1 pen incorrectly can render the medication ineffective. Semaglutide and tirzepatide are biological medicines, proteins that degrade when exposed to incorrect temperatures, direct light, or freezing. Unlike tablets, you cannot simply replace a damaged pen with a spare from the cupboard and carry on: degraded medication may appear normal but deliver little or no active drug.

This guide covers exactly what each pen requires, what happens if storage conditions are breached, and how to manage travel.

The Basic Rules for All GLP-1 Pens

The storage requirements are consistent across Wegovy (semaglutide 2.4mg), Ozempic (semaglutide up to 2mg), and Mounjaro (tirzepatide). The differences between pens are minor; the core rules are the same.

Before first use (unused pens):

• Store in a refrigerator between 2°C and 8°C
• Keep away from the freezer compartment and the back wall of the fridge (where temperatures can drop below 2°C)
• Store in original packaging to protect from light
• Do not use after the expiry date printed on the label

After first use (in-use pens):

• Can be stored at room temperature (up to 30°C) or in the refrigerator
• Must be used within 6 weeks (42 days) for Wegovy and Ozempic after first use
• Mounjaro: each pen is single-use only, so there is no "in-use" storage consideration
• Keep the pen cap on when not in use to protect the needle area from contamination

What Happens If a Pen Freezes?

Freezing is the most damaging storage error and unfortunately not uncommon. It happens when pens are stored near the back wall or ice compartment of the fridge, or during travel in cold climates.

When semaglutide or tirzepatide freezes, the protein structure of the active molecule is disrupted. The medication may still appear clear and colourless after thawing, but the biological activity is compromised. You cannot tell by looking at it whether it has been damaged.

What to do if your pen has frozen:

• Do not use the pen. Discard it and contact your prescriber or pharmacy for a replacement
• Do not attempt to thaw and use it; the damage is not reversible
• Check whether your insurance or prescribing service covers replacement pens in this circumstance

Signs that a pen may have been frozen: the liquid looks cloudy, has changed colour, or contains visible particles after thawing. However, visual inspection alone is not reliable: frozen-and-thawed medication can still look clear.

What Happens If a Pen Gets Too Warm?

Exposure to temperatures above 30°C degrades the medication over time. The 30°C threshold is the maximum sustained temperature, not a brief spike. A pen left in a hot car on a summer day, where car interior temperatures can reach 40-60°C within minutes, can be damaged within an hour.

Signs of heat-damaged medication:

• Liquid appears cloudy or discoloured
• Visible particles in the liquid
• Liquid looks thicker than usual

If the pen looks normal but you suspect it has been exposed to excessive heat for a significant period, contact your pharmacy or prescribing service for guidance. Do not assume the medication is still effective.

In the UK, a pen left at room temperature below 30°C is fine for up to 6 weeks after first use. During a typical British summer (average maximum around 20-22°C even in heatwaves, rarely sustained above 30°C), room temperature storage is generally safe. Take care during exceptionally hot spells.

Pen-Specific Storage Details

Wegovy (Semaglutide 2.4mg)

• Unused: refrigerate at 2-8°C in original packaging
• After first use: up to 30°C or refrigerate; use within 6 weeks (42 days)
• Each Wegovy pen is pre-filled and single-dose per injection, but the pen itself remains in use across the dose escalation schedule (not every injection uses a full new pen)
• Keep the pen cap on between uses

Ozempic (Semaglutide 1mg or 0.5mg)

• Unused: refrigerate at 2-8°C in original packaging
• After first use: up to 30°C or refrigerate; use within 6 weeks (42 days)
• Ozempic pens contain multiple doses, you will use the same pen for several weekly injections
• After 6 weeks, discard regardless of remaining medication

Mounjaro (Tirzepatide)

• Unused: refrigerate at 2-8°C in original packaging
• Each pen is single-use: inject once and dispose of the pen, there is no post-use storage consideration
• Remove from fridge 30 minutes before injecting for comfort
• Do not store in a freezer

Fridge Placement: Where Not to Store Your Pen

The typical domestic fridge is not uniformly 2-8°C throughout. The coldest areas, where freezing is a genuine risk, include:

• The back wall of the main compartment (particularly near the cooling element)
• The area directly adjacent to the ice-making compartment
• The bottom shelf directly beneath the freezer (in fridge-freezer models)

Safer placement:

• A middle shelf away from the back wall
• The door shelf (slightly warmer, but well above freezing and acceptable for GLP-1 pens)
• In the original packaging, standing upright

Do not store GLP-1 pens next to dairy products or raw meat in the door compartments where temperature varies with frequent opening, this is more about contamination hygiene than temperature. The middle shelf remains the most consistent position.

Travelling with GLP-1 Pens

By Air (UK Domestic or International)

GLP-1 pens should go in your hand luggage, not in checked baggage. The cargo hold of an aircraft can reach temperatures well below freezing, which would destroy the medication. This applies to all biological injectables.

You are legally permitted to carry GLP-1 pens through airport security in the UK and EU (and most internationally) with appropriate documentation:

• Carry the original packaging with the pharmacy label showing your name and the medication
• Carry a letter from your prescriber or GP confirming that the medication is prescribed for you and must be kept in hand luggage, many prescribers will provide this on request
• Liquids rules: injectable medications are exempt from the 100ml liquid restriction under UK aviation regulations; declare them at security
• Needles (if separate): carry a letter from your prescriber; expect to declare them and have them inspected

Most UK airports are familiar with this process. Declare the medication at security; do not try to hide it. Security staff are trained to deal with injectable medications.

Travelling by Car (UK Summer)

Do not leave your pen in a glove compartment or on a car seat in direct sunlight. Even on a mild UK summer day, the interior temperature of a parked car can exceed 40°C within 30 minutes. Keep the pen in an insulated cool bag (not next to an ice pack that could freeze it) when travelling.

Insulated Travel Cases

An insulated medication case maintains temperature between 2-8°C using cooling elements for approximately 6-10 hours, depending on the ambient temperature. These are useful for day trips, holidays where refrigeration is uncertain, or long flights.

When using a cooling case:

• Do not place the pen directly against the cooling element, wrap it in a cloth or use the case's divider
• Direct contact with a frozen cooling element can freeze the medication
• Check the case temperature periodically on longer journeys

Holiday Accommodation

Most hotel rooms and holiday apartments have fridges suitable for medication storage. In the UK, even basic accommodation typically has a mini-fridge. For self-catering holidays, confirm fridge availability before booking if you are on a weekly injectable.

If travelling to a hot country (Mediterranean, long-haul destinations), the room temperature rule (up to 30°C) should be respected, do not leave an in-use pen in a 35°C hotel room for a week. Keep it refrigerated.

The 6-Week In-Use Rule: What It Means in Practice

Once you start using a Wegovy or Ozempic pen, the 6-week clock starts, not the injection count. This means:

• If your dose frequency means you will not use all the doses in a pen within 6 weeks, you must still discard the pen at 6 weeks
• Do not try to consolidate doses or defer injections to use up a pen
• The 6-week rule reflects protein stability data, not remaining medication volume

For the dose escalation schedule and when each dose step typically occurs, see /guides/glp1-dose-escalation-guide-uk.

Light and Packaging

Semaglutide and tirzepatide should be stored in their original packaging to protect from light. Prolonged exposure to direct sunlight or UV light degrades biological proteins. The packaging is opaque specifically to provide this protection.

When not injecting, keep the pen cap on and the pen in its box. Do not store pens on a windowsill, in a transparent container on a worktop, or anywhere with consistent light exposure.

Disposing of Pens and Needles

Pens must be disposed of in a sharps bin, not household waste. Needles are clinical waste and present a needle-stick injury risk to waste handlers.

NHS and local council sharps collection: free sharps bins are available from your GP surgery, pharmacy, or local council waste service. Many pharmacies accept used sharps bins for clinical disposal.

Do not recap needles in a way that risks needle-stick injury. Discard directly into the sharps bin after use.

Checking Before Injecting

Before every injection, check:

1. The pen has not expired
2. The liquid is clear and colourless (no cloudiness, particles, or discolouration)
3. The pen has not been frozen (check for signs, cloudiness, unusual appearance after any period of very cold storage)
4. You are within the 6-week window for in-use pens

If in doubt about any of these, do not use the pen. Contact your pharmacy or prescribing service for guidance.

Related Guides

• Where to Inject Wegovy and Ozempic
• GLP-1 Dose Escalation Guide
• Finding the Right GLP-1 Prescriber in the UK