Semaglutide (the active ingredient in Ozempic, Wegovy, and some compounded formulations) is a temperature-sensitive biologic medication that must be handled carefully to remain safe and effective. Like most injectable peptides and proteins, it can degrade when exposed to heat, light, or freezing, which reduces potency and may increase the risk of bacterial growth or other safety issues. Patients frequently ask what happens if the pen or vial gets warm during shipping, travel, power outages, or accidental room-temperature storage.
The short answer is that brief warmth usually does not ruin the medication, but prolonged or extreme heat can degrade semaglutide and make it less effective or unsafe to use. Manufacturer guidelines provide clear temperature ranges for both unopened and in-use pens, and exceeding those limits for too long typically means the product should be discarded. Compounded versions often have stricter rules because they lack the same stabilizing excipients found in branded products.
This article explains official storage requirements for branded and compounded semaglutide, what happens at different temperatures, how to recognize a compromised pen or vial, safe travel and emergency storage tips, and what to do if your medication has been exposed to warmth.
Official Storage Rules for Branded Semaglutide Pens
Novo Nordisk provides identical storage instructions for Ozempic and Wegovy pens. Unopened pens must be refrigerated at 2–8 °C (36–46 °F) until the expiration date printed on the label. Do not freeze the pens, and do not use any pen that has been frozen—even if it has thawed completely—because freezing can cause the solution to separate or degrade.
Once the pen is used for the first time (after removing the cap and performing the first injection), it can be stored either refrigerated or at controlled room temperature up to 30 °C (86 °F). In both cases, the pen must be discarded after 56 days (8 weeks), whichever comes first, even if solution remains. Protect the pen from direct sunlight and excessive heat at all times.
These rules allow flexibility for travel or short periods without refrigeration after the pen is in use. The 56-day limit is based on stability testing that confirms potency, sterility, and physical integrity within that window under approved conditions.
Branded Pen Storage Summary
- Unopened: Refrigerate at 2–8 °C until expiration date
- After first use: Refrigerate or keep at ≤30 °C (86 °F)
- Maximum duration after first use: 56 days (discard after 8 weeks)
- Never freeze or expose to direct sunlight
Follow the carton and pen label instructions exactly.
What Happens When Semaglutide Gets Warm
Semaglutide is a peptide that can denature (lose its three-dimensional structure) or aggregate when exposed to high temperatures for prolonged periods. Denaturation reduces the drug’s ability to bind to GLP-1 receptors, lowering potency and effectiveness. Aggregation can make the solution cloudy or form visible particles, which may increase injection-site reactions or reduce absorption.
Brief exposure to warm temperatures (for example, 30–40 °C / 86–104 °F for a few hours) usually does not cause clinically meaningful degradation in branded pens. Novo Nordisk stability data show that pens remain within specification after short excursions up to 40 °C. However, the longer and hotter the exposure, the greater the loss of potency.
Extreme heat (above 40–50 °C / 104–122 °F) for more than a few hours can cause significant degradation. The solution may become cloudy, discolored, or contain particles, and potency can drop substantially. Any pen that has been exposed to such conditions should be discarded, even if it looks normal.
Temperature Impact Guide
- 2–30 °C (36–86 °F): Safe for in-use pens up to 56 days
- 30–40 °C (86–104 °F): Short excursions (hours) usually okay
- >40 °C (>104 °F): Risk of degradation increases rapidly
- Freezing (≤0 °C / 32 °F): Destroys the drug—discard immediately
Discard any pen that has been frozen or exposed to excessive heat for a prolonged time.
Storage Rules for Compounded Semaglutide
Compounded semaglutide (custom-made by pharmacies) does not have one universal storage rule because formulations vary between pharmacies. Most compounding pharmacies require continuous refrigeration at 2–8 °C (36–46 °F) for both unopened and in-use vials. Room-temperature storage is generally not permitted unless the pharmacy specifically states it is acceptable for a limited time.
The beyond-use date (BUD) is typically 28–30 days after the vial is first punctured or the syringe is filled. Some pharmacies assign shorter BUDs (14–28 days) if preservatives are minimal or absent. Freezing is not recommended for compounded versions either, as it can degrade the active ingredient or cause the solution to separate.
Always follow the exact BUD and storage instructions provided by the compounding pharmacy on the label. If the label is missing or unclear, do not use the vial—contact the pharmacy immediately for clarification.
Compounded Semaglutide Storage Summary
- Unopened vial: Refrigerate at 2–8 °C
- After first use: Refrigerate continuously
- Beyond-use date: Usually 28–30 days after first puncture
- Do not freeze or leave at room temperature long-term
Pharmacy instructions take priority over general guidelines.
Comparison: Temperature Tolerance of Branded vs Compounded Semaglutide
| Aspect | Branded Semaglutide (Ozempic/Wegovy) | Compounded Semaglutide |
|---|---|---|
| Unopened storage | Refrigerate until expiration date | Refrigerate until beyond-use date |
| After first use | Refrigerate or room temp ≤30 °C (86 °F) | Refrigerate continuously |
| Maximum time after first use | 56 days | 28–30 days (check pharmacy label) |
| Tolerance to brief warmth | Safe for hours up to 40 °C | Usually not recommended; check label |
| Freezing allowed? | No—discard if frozen | No—discard if frozen |
This table highlights the main storage differences. Branded pens offer more flexibility after first use, while compounded versions require stricter refrigeration.
How to Tell If Semaglutide Has Been Damaged by Heat
Inspect the solution before every injection. Branded pens should contain a clear, colorless liquid with no visible particles, cloudiness, or discoloration. If the solution looks cloudy, has particles, or has turned yellow/brown, discard the pen immediately—even if it has been stored correctly.
Compounded vials should also be clear and colorless. Any cloudiness, floating particles, separation, or unusual odor indicates possible degradation or contamination. Discard the vial and contact the pharmacy for a replacement.
If the pen or vial has been exposed to known excessive heat (e.g., left in a hot car for several hours), discard it even if it looks normal. Potency can be reduced without visible changes, and using a degraded product may lead to poor blood sugar control or inadequate weight-loss effect.
Visual & Sensory Checks Before Each Use
- Clear, colorless solution (no cloudiness or particles)
- No unusual odor
- No discoloration (yellowing or browning)
- No leaks or damage to pen/vial
- Within printed expiration or beyond-use date
If anything looks or smells off, do not use it.
Safe Travel & Emergency Storage Tips
For short trips (a few days), opened branded pens can stay at room temperature if kept below 30 °C (86 °F). Use an insulated cooler bag with gel packs (not loose ice) to maintain 2–8 °C during longer travel. Place the pen in a carry-on bag—never check it in luggage where temperatures can become extreme.
Compounded vials usually require refrigeration during travel. Use a medical-grade cooler bag with frozen gel packs and monitor temperature if possible. Avoid placing the vial directly on ice packs to prevent freezing.
After travel, return the medication to the refrigerator promptly. Discard if it has been exposed to excessive heat or freezing.
Travel Storage Tips
- Use an insulated cooler bag with gel packs
- Keep medication in carry-on luggage
- Avoid direct sunlight or hot car interiors
- Carry a copy of your prescription
- Plan extra time for security screening
These steps keep the medication safe during trips.
What to Do If Your Semaglutide Gets Warm
If a pen or vial has been exposed to warmth, evaluate the duration and temperature. Brief exposure (a few hours at 30–40 °C) is usually safe for branded pens that are already in use. Longer or hotter exposure (above 40 °C for more than a few hours) increases the risk of degradation—discard the product.
If the pen or vial looks abnormal (cloudy, particles, discoloration), discard it immediately. If it looks normal but has been exposed to known excessive heat, err on the side of caution and discard it. Using a degraded product can lead to poor blood sugar control or inadequate weight-loss effect.
Contact your pharmacy or prescribing provider for guidance and to arrange a replacement. Keep a backup supply when possible, especially during travel or summer months when heat exposure is more likely.
Conclusion
Semaglutide remains stable and safe within the manufacturer’s specified temperature ranges (refrigerated unopened, refrigerated or ≤30 °C after first use for branded pens, continuous refrigeration for most compounded versions). Brief warmth usually does not ruin the medication, but prolonged or extreme heat can degrade potency and should lead to discarding the pen or vial. Always inspect the solution before use, follow exact storage instructions, and contact your pharmacist or provider if you are unsure about a product’s condition. This article is for informational purposes only and not medical advice—proper storage is essential for maintaining effectiveness and safety during treatment.
FAQ
How long can Ozempic or Wegovy stay out of the fridge after first use?
Opened branded pens are stable at room temperature up to 30 °C (86 °F) for 56 days. After that, discard even if refrigerated. Protect from direct light and extreme heat.
How long does compounded semaglutide last in the fridge?
Compounded semaglutide usually has a beyond-use date of 28–30 days after first puncture or filling. Always follow the exact date on the pharmacy label. Keep refrigerated continuously.
Can I freeze semaglutide pens or vials?
No—freezing damages the active ingredient. Discard any pen or vial that has been frozen, even if it thaws. Never store in the freezer compartment or near cooling vents.
What happens if semaglutide is left out too long?
Branded pens left out longer than 56 days after first use lose potency and should be discarded. Compounded versions left out for more than a few hours (check pharmacy instructions) may degrade or become contaminated. When in doubt, discard.
How can I tell if my semaglutide is still good?
Check that the solution is clear and colorless with no particles, cloudiness, or discoloration. For branded pens, ensure you are within 56 days of first use. For compounded vials, stay within the pharmacy’s beyond-use date.
Should I refrigerate semaglutide during travel?
Yes—use an insulated cooler bag with gel packs to keep it at 2–8 °C. For short trips, opened branded pens can stay at room temperature up to 30 °C. Keep in carry-on luggage.
What if my semaglutide pen looks cloudy?
Do not use it. Cloudiness, particles, or discoloration indicate possible contamination or degradation. Discard immediately and contact your pharmacy or prescriber for a replacement.
How should I store unopened semaglutide pens?
Keep unopened branded pens refrigerated at 2–8 °C until the expiration date on the label. Do not freeze. Compounded vials should also be refrigerated continuously until first use.
Can semaglutide be stored at room temperature the whole time?
Branded pens can be kept at room temperature after first use for up to 56 days. Compounded versions usually require continuous refrigeration. Follow the specific instructions provided with your product.
What should I do if I’m not sure how long my semaglutide has been out of the fridge?
Err on the side of caution and discard it if it has been outside recommended conditions for more than a short time. Contact your pharmacy or prescriber for guidance. Using compromised medication can reduce effectiveness or cause harm.
Dr. Usman is a medical content reviewer with 12+ years of experience in healthcare research and patient education. He specializes in evidence-based health information, medications, and chronic health topics. His work is based on trusted medical sources and current clinical guidelines to ensure accuracy, transparency, and reliability. Content reviewed by Dr. Usman is for educational purposes and does not replace professional medical advice.