Wegovy (semaglutide) is a GLP-1 receptor agonist licensed in the UK for weight management in adults with obesity or overweight with weight-related comorbidities. Proper storage is essential to maintain the medication's effectiveness and safety. Understanding how long Wegovy remains stable in the fridge—and what happens when storage guidelines aren't followed—helps patients use their medication correctly and avoid wastage. This article explains UK-approved storage requirements, shelf life for unopened and in-use pens, and how to recognise when your Wegovy pen may no longer be safe to use.

Wegovy Storage Requirements and Refrigeration Guidelines

Wegovy (semaglutide) is a glucagon-like peptide-1 (GLP-1) receptor agonist licensed in the UK for weight management in adults with obesity or overweight with weight-related comorbidities. The usual maintenance dose is 2.4 mg once weekly, with 1.7 mg as an alternative if the higher dose is not tolerated.

The Medicines and Healthcare products Regulatory Agency (MHRA) approved product information specifies that unopened Wegovy pens must be stored in a refrigerator at temperatures between 2°C and 8°C. The pens should be kept in their original carton to protect them from light. It is essential to store Wegovy away from the freezer compartment, as freezing will irreversibly damage the medication. If a pen has been frozen, it must be discarded and should not be used.

Once you begin using a Wegovy pen, storage requirements become more flexible. An in-use pen may be stored either in the refrigerator (2°C to 8°C) or at room temperature (not exceeding 30°C) for up to 6 weeks. This flexibility allows patients to carry their pen with them for convenience, particularly when travelling or during daily activities. However, the pen should always be kept with the cap on when not in use to protect it from light.

Importantly, you should always remove the needle after each injection and store the pen without a needle attached. Use a new sterile needle for each injection and never share your pen with others. Keep Wegovy pens out of the sight and reach of children.

Patients should avoid storing Wegovy pens near heat sources or in direct sunlight. As a general good practice, avoid storing medicines in environments with high humidity. Proper storage is fundamental to ensuring the medication retains its potency and remains safe for administration.

How Long Does Wegovy Last in the Fridge?

Understanding the shelf life of Wegovy when stored correctly is crucial for both medication safety and cost-effectiveness. Unopened Wegovy pens stored continuously in the refrigerator at 2°C to 8°C remain stable until the expiry date printed on the carton and pen label. This expiry date is determined by the manufacturer based on stability testing.

Patients should always check the expiry date before using a new pen and should never use Wegovy beyond this date, even if it has been stored correctly. Pharmacies in the UK typically ensure adequate shelf life remains when dispensing medication, but it is good practice to verify this when collecting your prescription, particularly if you are receiving multiple pens at once.

Once a Wegovy pen is first used, the storage timeline changes significantly. From the moment you administer your first dose, the pen may be kept for up to 6 weeks (42 days), whether stored in the refrigerator or at room temperature not exceeding 30°C. This 6-week period applies regardless of how many doses remain in the pen. It is advisable to write the date of first use on the pen label to help track this timeframe accurately.

For patients following the standard Wegovy dosing schedule—one injection per week—a single pen should last for multiple doses depending on the strength. However, the 6-week in-use limit means that any medication remaining after this period must be discarded, even if doses remain. This precaution ensures the medication maintains its sterility and stability. Patients should plan their prescription refills accordingly and consult their GP or pharmacist if they have concerns about medication wastage or dosing schedules.

What Happens If Wegovy Is Stored Incorrectly?

Improper storage of Wegovy can compromise the medication's chemical structure, reducing its therapeutic effectiveness and potentially creating safety concerns. Semaglutide, the active pharmaceutical ingredient in Wegovy, is a modified peptide that is sensitive to temperature extremes, light exposure, and physical stress. When storage guidelines are not followed, the medication may degrade, leading to reduced effectiveness for weight management.

Freezing is the most critical storage error to avoid. If Wegovy is accidentally frozen, the protein structure of semaglutide becomes irreversibly damaged. Frozen medication cannot be salvaged by thawing and must be discarded immediately. Patients should never use a pen that has been frozen. If you are unsure whether your pen has been frozen, check if the liquid appears cloudy or contains particles.

Exposure to excessive heat (temperatures above 30°C) can also degrade semaglutide. Prolonged heat exposure can reduce the medication's potency, meaning patients may not achieve the expected therapeutic benefits. This is particularly relevant during summer months or when travelling to warmer climates. Patients should avoid leaving pens in hot cars, near radiators, or in direct sunlight.

Extended storage beyond the 6-week in-use period raises concerns about both chemical degradation and sterility. Once the pen's seal is broken with the first injection, sterility cannot be assured beyond the in-use period. The MHRA-approved 6-week limit balances medication stability with safety. Using Wegovy beyond this timeframe is not recommended, as there is no official evidence supporting its safety or efficacy after this period. If you have stored your medication incorrectly, contact your pharmacist or GP for advice rather than using potentially compromised medication.

If you experience any suspected side effects from Wegovy, report them via the MHRA Yellow Card scheme at yellowcard.mhra.gov.uk or via the Yellow Card app.

Signs Your Wegovy Pen May No Longer Be Safe to Use

Recognising when a Wegovy pen should not be used is an essential aspect of medication safety. Before each injection, patients should perform a visual inspection of the medication through the pen window. According to the Patient Information Leaflet, Wegovy should appear as a clear and colourless solution. Any deviation from this appearance warrants caution and further assessment.

Key warning signs that indicate your Wegovy pen should be discarded include:

• Cloudiness or turbidity – The solution should be completely clear. If it appears milky, hazy, or cloudy, this suggests protein aggregation or contamination.

• Visible particles or precipitates – Any floating particles, sediment, or crystalline material indicates chemical degradation. Do not attempt to use the pen if particles are present, even if they appear small.

• Discolouration – If the solution has any unusual colouration, this suggests the medication has degraded and should not be used.

• Damaged or cracked pen – Physical damage to the pen casing, needle, or viewing window compromises sterility and dose accuracy. Never use a damaged pen.

• Expired date – Always check the expiry date printed on the pen. Using expired medication is not recommended, as potency cannot be guaranteed.

• Uncertain storage history – If you cannot confirm the pen has been stored correctly (e.g., after a power cut affecting your refrigerator, or if left in a hot environment), it is safer to obtain a replacement.

Remember to remove the needle after each injection and store the pen without a needle attached. Always use a new needle for each injection and never share your pen with others.

For safe disposal, place used needles in a sharps bin and return used pens and needles to a pharmacy for safe disposal. Do not discard needles in household waste.

If you identify any warning signs, do not use the pen. Contact your community pharmacist or GP practice for guidance on obtaining a replacement. Most pharmacies can provide advice on medication safety and may be able to arrange an emergency supply if clinically appropriate. The NHS 111 service can also provide out-of-hours advice if you have concerns about your medication and cannot reach your usual healthcare provider.

Frequently Asked Questions