How to store weight loss injections properly is essential for maintaining their effectiveness and safety. Weight loss injections such as semaglutide (Wegovy) and liraglutide (Saxenda) are biological medicines containing delicate proteins that degrade when exposed to incorrect temperatures, light, or physical stress. Improper storage can render these medications ineffective, compromising your weight management treatment and potentially affecting blood glucose control in patients with type 2 diabetes. This guide explains the precise storage conditions required for weight loss injections, covering refrigeration requirements, travelling considerations, and common mistakes to avoid, ensuring you receive the full therapeutic benefit of your prescribed treatment whilst minimising safety risks.
Quick Answer: Weight loss injections must be stored refrigerated at 2°C to 8°C before first use, never frozen, and protected from light to maintain their therapeutic effectiveness.
Weight loss injections, particularly glucagon-like peptide-1 (GLP-1) receptor agonists such as semaglutide (Wegovy) and liraglutide (Saxenda), are biological medicines that require careful storage to maintain their therapeutic efficacy and safety. These medications are protein-based compounds that can degrade when exposed to inappropriate temperatures, light, or physical stress, potentially rendering them ineffective or unsafe for use.
Improper storage can lead to structural changes in the active pharmaceutical ingredient, compromising the medication's ability to regulate blood glucose levels and suppress appetite effectively. When these injections are stored outside recommended conditions, the delicate protein structure may denature or aggregate, reducing potency. This is particularly concerning given the significant investment patients make in these treatments, both financially and in terms of their weight management journey.
Patient information leaflets (PILs) emphasise that patients must follow storage instructions precisely as outlined. Failure to do so may result in treatment failure, necessitating dose adjustments or medication changes. For patients with type 2 diabetes who use GLP-1 receptor agonists for diabetes management (e.g., Ozempic), degraded medication could lead to reduced glycaemic control.
Key considerations include:
Maintaining consistent refrigeration temperatures
Protecting medications from light exposure
Avoiding freezing, which irreversibly damages the formulation
Checking expiry dates regularly
Proper storage practices ensure you receive the full therapeutic benefit of your prescribed weight loss injection whilst minimising safety risks and avoiding unnecessary waste of these valuable medications.
Mounjaro® is the most innovative GLP-1 medication proven to dramatically curb appetite, hunger, and cravings to help professional men achieve substantial weight loss.
Start Here
Wegovy® is a weekly injectable GLP-1 medication with proven effectiveness in reducing appetite, hunger, and cravings to help busy professionals lose significant weight.
Start HereMost weight loss injections approved in the UK require refrigeration between 2°C and 8°C before first use. This temperature range is critical for preserving the stability of GLP-1 receptor agonists and other biological weight loss medications. Standard domestic refrigerators typically maintain this range, though it's advisable to store medications in the main body of the fridge rather than the door, where temperature fluctuations are more common. Keep pens away from the cooling element or back wall of the refrigerator.
The medications must never be frozen. Freezing causes irreversible damage to the protein structure, rendering the injection ineffective and potentially unsafe. If your medication has been accidentally frozen—even if subsequently thawed—it must be discarded and replaced. Check the appearance carefully, as ice crystals or unusual cloudiness may indicate previous freezing.
Protection from light is another essential storage requirement. Most weight loss injections are supplied in packaging designed to shield the medication from light exposure. Keep the pen in its original carton when not in use, as ultraviolet and visible light can degrade the active ingredient over time.
Once opened or removed from refrigeration, storage requirements vary by product:
Wegovy (semaglutide): Single-use pens can be kept at temperatures up to 30°C for up to 6 weeks after removal from refrigeration
Saxenda (liraglutide): After first use, can be stored at temperatures up to 30°C for 1 month or kept refrigerated
Additional storage principles:
Store away from the freezer compartment
Keep out of reach of children
Do not store in bathrooms where humidity and temperature vary
Maintain original packaging until ready to use
Always refer to the specific storage instructions in your medication's Patient Information Leaflet available from the electronic medicines compendium (emc).
Unopened weight loss injections should remain refrigerated at 2°C to 8°C until you're ready to begin treatment. Store them in their original carton to protect from light, ideally on a middle shelf of your refrigerator where temperature remains most stable. Never place unopened pens in the freezer compartment or directly against the back wall of the fridge, where they might freeze. Check expiry dates upon receipt and organise your supply so you use the earliest expiring medication first.
Before injection, you may remove the pen from the refrigerator approximately 30 minutes before use to allow it to reach room temperature. This is for comfort during injection; according to product SmPCs, letting the medication warm to room temperature does not affect its efficacy.
Once opened or removed from refrigeration, storage requirements vary by product:
Wegovy (semaglutide): These are single-use pens. After removal from refrigeration, they can be stored at temperatures up to 30°C for up to 6 weeks. After injection, the pen should be discarded.
Saxenda (liraglutide): After first use, pens can be stored at temperatures up to 30°C for 1 month or kept refrigerated. For multi-dose pens like Saxenda, write the date of first use on the pen label.
Important practices for pens:
Keep the pen cap on when not in use to protect from light
Never store with a needle attached, as this can cause leakage or air bubbles
Discard after the specified in-use period, even if medication remains
Store away from direct heat sources and sunlight
If you're uncertain about storage duration or conditions, contact your pharmacist rather than risk using potentially compromised medication. The NHS advises that proper storage practices are fundamental to medication safety and treatment success.
Travelling with weight loss injections requires advance planning to maintain proper storage conditions throughout your journey. For short trips within the UK, an insulated medication travel case with ice packs can maintain appropriate temperatures for several hours. However, ensure ice packs don't directly contact the medication pen, as freezing will damage it irreversibly. Place a barrier such as a cloth between ice packs and medication.
When flying, always carry weight loss injections in your hand luggage rather than checked baggage. Aircraft hold temperatures can drop below freezing, destroying your medication. According to NHS guidance on taking medicines abroad, airport security regulations permit passengers to carry necessary medications, including injections and needles, but you should carry your prescription or a letter from your GP confirming medical necessity. Keep medications in original packaging with pharmacy labels clearly visible.
For longer journeys or holidays, research refrigeration availability at your destination. Many hotels can provide refrigerator access in rooms or will store medications in their facility refrigerator if requested in advance. If refrigeration isn't available, remember that weight loss injections can remain at room temperature (below 30°C) for limited periods, which vary by product:
Wegovy (semaglutide): Up to 6 weeks at temperatures up to 30°C
Saxenda (liraglutide): Up to 1 month at temperatures up to 30°C
These durations count towards the total allowed time out of refrigeration.
Travel checklist:
Insulated medication travel pouch
Sufficient supply plus extra in case of delays
Prescription or GP letter
Sharps container for safe needle disposal
Copy of storage instructions
Contact details for your prescriber
When travelling to hot climates, never leave medication in vehicles, where temperatures can exceed 50°C within minutes. If you're concerned your medication has been exposed to extreme temperatures during travel, consult a pharmacist before use. Patient safety must always take precedence over completing a partially used pen.
Recognising when a weight loss injection has been compromised is essential for both safety and treatment efficacy. Visual inspection before each injection is a critical safety step. According to product Patient Information Leaflets, GLP-1 receptor agonist solutions should appear clear and colourless (or almost colourless) with no particles. Any cloudiness, discolouration, or visible particles indicates the medication should not be used and must be returned to your pharmacy for assessment.
If you observe ice crystals within the solution or the liquid appears frozen or partially frozen, the medication has been irreversibly damaged and must be discarded. Even after thawing, previously frozen medication cannot be used safely. Similarly, if the solution has changed colour—becoming darker, brownish, or showing unusual tints—this suggests degradation of the active ingredient.
Changes in consistency also warrant concern. If the normally free-flowing liquid appears thickened, gel-like, or contains floating particles or sediment, do not inject it. These physical changes indicate protein aggregation or contamination. Additionally, if the pen mechanism feels stiff, doesn't advance properly, or leaks medication, this suggests mechanical compromise that could affect dose accuracy.
Other warning signs include:
Medication stored beyond the specified period after opening or removal from refrigeration (Saxenda: 1 month; Wegovy: 6 weeks)
Exposure to temperatures above 30°C for extended periods
Storage with needle attached between doses
Damaged or cracked pen casing
Expired medication (check date on carton and pen)
If you're uncertain about your medication's integrity, do not use it. Contact your pharmacist or prescriber for guidance. Using compromised medication may result in inadequate therapeutic effect. Your pharmacist can arrange replacement medication and provide advice on proper storage going forward. If you experience any suspected side effects or believe your medication is defective, report this through the MHRA Yellow Card scheme.
One of the most frequent storage errors is storing medication in the refrigerator door. Whilst convenient, the door experiences significant temperature fluctuations each time the fridge opens, potentially exposing medication to temperatures outside the recommended 2°C to 8°C range. Always store weight loss injections on a middle shelf where temperature remains most stable. Consider using a fridge thermometer to monitor that your refrigerator maintains the correct temperature range.
Leaving needles attached between injections is another common mistake that can compromise medication quality. An attached needle creates a pathway for air to enter the cartridge, potentially causing oxidation of the medication and introducing contamination. It can also lead to leakage and inaccurate dosing. Always remove and safely dispose of needles immediately after each injection in a proper sharps bin, available from your GP surgery or pharmacy.
Many patients inadvertently freeze their medication by placing it too close to the freezer compartment or against the back wall of the refrigerator where temperatures drop lowest. Even brief freezing irreversibly damages the protein structure. Store pens away from the cooling element and back wall of the refrigerator.
Continuing to use medication beyond the specified storage period is a significant safety concern. Product-specific limits must be followed:
Wegovy (semaglutide): Single-use pens can be kept at temperatures up to 30°C for up to 6 weeks after removal from refrigeration
Saxenda (liraglutide): After first use, can be stored at temperatures up to 30°C for 1 month or kept refrigerated
Additional mistakes to avoid:
Storing in bathrooms where humidity and temperature fluctuate
Removing medication from original packaging prematurely
Failing to record the date of first use on multi-dose pens
Exposing pens to direct sunlight or heat sources
Sharing medication or storage containers with others
Not checking expiry dates before use
If you've made any of these storage errors, consult your pharmacist before using the medication. For information on safe disposal of used needles and other sharps, contact your local council, GP surgery or pharmacy, who can provide appropriate sharps bins and advice on local disposal arrangements.
Once opened or removed from refrigeration, weight loss injections can be stored at room temperature up to 30°C for limited periods: Wegovy for up to 6 weeks and Saxenda for up to 1 month. Unopened pens must remain refrigerated at 2°C to 8°C.
Freezing causes irreversible damage to the protein structure of weight loss injections, rendering them ineffective and unsafe. If your medication has been frozen, even if subsequently thawed, it must be discarded and replaced—do not use it.
Always carry weight loss injections in your hand luggage, never in checked baggage where temperatures can drop below freezing. Use an insulated medication case with ice packs (ensuring they don't directly contact the pen), and carry your prescription or a GP letter confirming medical necessity for airport security.
All medical content on this blog is created based on reputable, evidence-based sources and reviewed regularly for accuracy and relevance. While we strive to keep content up to date with the latest research and clinical guidelines, it is intended for general informational purposes only.
DisclaimerThis content is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare professional with any medical questions or concerns. Use of the information is at your own risk, and we are not responsible for any consequences resulting from its use.
