Semaglutide is a protein-based medication, and heat breaks down proteins. If your pen gets warm, the drug can lose potency, meaning it won’t work as well or at all. The critical threshold is 86°F (30°C). Below that, you have a window of time where the medication stays stable. Above that, the manufacturer says the pen should not be used.
The Temperature Limits
Both Ozempic and Wegovy pens are designed to be stored in a refrigerator between 36°F and 46°F before first use. Once you start using a pen or take it out of the fridge, it can safely stay at warmer temperatures for a limited number of days, but only up to 86°F.
For Ozempic, that window is 56 days at temperatures between 59°F and 86°F. For Wegovy, it’s shorter: 28 days between 46°F and 86°F, and the cap must not have been removed yet. After those time limits, you discard the pen regardless of how much medication is left. If the pen goes above 86°F at any point, those timelines no longer apply. Novo Nordisk states plainly that Ozempic “can be used as long as the product has not been exposed to temperatures below 36°F or above 86°F.”
Rybelsus, the oral tablet form of semaglutide, is more forgiving. It’s stored at room temperature (68°F to 77°F) and can handle brief excursions up to 86°F without concern.
What “Too Warm” Actually Means
The 86°F ceiling matters because it’s surprisingly easy to exceed. A car parked in the sun on a mild 75°F day can reach interior temperatures above 100°F within 30 minutes. A mailbox in direct sunlight, a bag left on a sunny counter, or a suitcase in a hot trunk can all push well past the limit. The FDA labeling specifically warns: “Do not leave it in a car or other place where it can get too hot or too cold.”
Brief warmth below 86°F is not a problem. If your pen sat on the kitchen counter overnight in a 72°F house, it’s fine. That time simply counts against your 56-day (Ozempic) or 28-day (Wegovy) room-temperature window. The concern is sustained or extreme heat, not a few degrees above refrigerator temperature.
How to Tell if Your Pen Is Damaged
Semaglutide solution should be completely clear, colorless, and free of particles. Before every injection, hold the pen up to the light and look through the cartridge window. If you see cloudiness, discoloration, or tiny floating specks, the protein has likely degraded. A pen that has been frozen and thawed will also often show visible changes.
The tricky part is that heat damage doesn’t always produce visible signs. A pen that sat in a hot car for two hours might look perfectly normal but have reduced potency. You wouldn’t necessarily know until you noticed the medication wasn’t controlling your appetite or blood sugar the way it usually does. This is why the manufacturer sets a hard temperature ceiling rather than relying on visual inspection alone. That said, Novo Nordisk does recommend inspecting for “precipitation, or change in color or clarity that may indicate a loss in potency,” so a visual check is still worth doing as a secondary safeguard.
Freezing Is Worse Than Warming
If you’re weighing whether heat or cold is the bigger risk, freezing is actually more destructive. The FDA label is absolute on this point: “Do not use OZEMPIC if it has been frozen.” There is no grace period, no visual inspection that can clear it. Ice crystals physically shatter the protein molecules in ways that cannot be reversed by thawing. A frozen pen goes in the trash.
Heat damage, by contrast, happens on a spectrum. A pen that briefly touched 90°F is in a gray area. A pen that sat at 110°F for hours is almost certainly compromised. The manufacturer draws the line at 86°F because that’s the temperature up to which they can guarantee stability for the labeled duration.
Practical Tips for Warm Weather and Travel
If you’re traveling or dealing with summer heat, a few simple habits protect your medication. A small insulated pouch with a cool pack (not frozen solid, which risks freezing the pen) keeps temperatures in the safe range for most of a day. Pharmacies and online retailers sell medication travel cases designed for this purpose. When flying, always carry your pen in your personal bag rather than checked luggage, since cargo holds can swing to extreme temperatures.
At home, store unopened pens in the refrigerator, not the door shelf where temperatures fluctuate every time you open it. Place them toward the back on a middle shelf. Once you’re actively using a pen, keeping it in the fridge between injections is still the safest approach, though room temperature storage within the labeled time window is perfectly acceptable.
If you’re unsure whether your pen exceeded 86°F, consider when and where it was left. A pen forgotten in a climate-controlled office for a few hours is almost certainly fine. A pen left in a parked car on a summer afternoon is not. When in doubt, the safest choice is to replace the pen. Using a degraded dose means the medication may not be doing its job, and you won’t have a clear way to know until you notice your symptoms returning.