My GLP-1 Froze: Is It Still Good?
- Jennifer Hardy
- Sep 20
- 7 min read
I keep seeing questions about frozen semaglutide and frozen tirzepatide, usually after someone makes a mistake like leaving it in the car or accidentally putting it in the freezer. The FDA-approved versions of these drugs are supposed to be refrigerated, not frozen, so the question is what happens when your expensive GLP-1 pen turns into an ice block?
Is it dangerous? Can thawing bring it back? Or is the money down the drain? Let’s break down what the manufacturers say, what science says, and what you should do. Plus, find out what really happens when Ozempic, Wegovy, or Zepbound exceed the temperature thresholds.
TIP: If you're looking for permission to use GLP-1s after exceeding temperatures, you won't find it here.
What the Drugmakers Say
Both Novo Nordisk (maker of semaglutide products Ozempic, Wegovy, and Rybelsus) and Eli Lilly (maker of tirzepatide products Mounjaro and Zepbound) are clear in their storage instructions: do not freeze these medications.
Semaglutide (Novo Nordisk): Store between 36°F and 46°F. Do not freeze. If a pen freezes, throw it away.
Tirzepatide (Eli Lilly): Same guidance. Keep refrigerated, never frozen. If it has been frozen, discard it.
This is black-and-white from the companies themselves. Neither manufacturer says, “Give it a shot and see what happens.” Their official position is that once frozen, the drug should not be used.
Why Freezing Matters
The warning isn’t just about being overly cautious. It comes down to chemistry.
Semaglutide: It’s a peptide, basically a chain of amino acids folded into a specific shape. That shape is what lets it bind to GLP-1 receptors and work the way it should. Freezing can cause those folds to unravel or clump together. Even if the liquid looks fine once thawed, the drug inside may have lost its structure.
Tirzepatide: Same story. It’s also a peptide, just a bigger and slightly different one. Freezing can denature the molecule and reduce its ability to act at GLP-1 and GIP receptors.
Once a peptide drug has been damaged by freezing, there’s no way to refold it back to its active shape. Think of it like scrambling an egg. You can heat it, cool it, even freeze and thaw it, but it’s never going back to raw egg form.
Is It Dangerous to Inject a Frozen or Thawed Pen?
This is where it’s important to separate fear from facts. A frozen GLP-1 pen is not toxic. Injecting it isn’t going to poison you or suddenly cause dangerous side effects. The issue is effectiveness.
If you inject a dose from a pen that has been frozen, you may not be getting the actual drug effect. That means your blood sugar might not improve, or your weight loss plan could stall, even though you’re still experiencing side effects like nausea. The risk is wasted medication, not poisoning.
For people using these drugs for blood sugar control, the loss of effectiveness carries much more immediate risk than for someone who might “only” see slower or less weight loss. Also, it's important to note that you can't tell if the medicine is still "good" by looking at it. Thawed GLP-1s will look the same as the original version to the naked eye.
Why Frozen GLP-1s Keep Happening
GLP-1s are among the most expensive medications on the market. Many people pay $1,000 or more a month out of pocket. Losing a pen to freezing feels like throwing money out the window.
Yet it happens often because the instructions aren’t always clear or realistic:
Shipments get left on porches or in cars in subzero weather.
Travelers mistakenly put GLP-1s in checked baggage, where there isn't climate control.
Patients assume refrigeration means colder is better and mistakenly put pens in the freezer.
At GLP-1 Newsroom, we don’t recommend compounded GLP-1s. They were only permitted during shortages, and since the FDA has ended that allowance, they are no longer considered legally permitted.
However, it's worth mentioning because my first two months of use were compound tirzepatide, before the rules changed. In that case, the medication was supposed to be frozen and thawed before use. I share this to stress one point: always follow the manufacturer’s instructions and confirm with your pharmacist so you have the most current, accurate guidance.
Preventing Frozen Semaglutide and Frozen Tirzepatide
A few simple steps can help you avoid the headache:
Don’t store pens in the freezer, ever.
If traveling, keep pens in an insulated bag, but not on ice.
Bring them inside quickly if shipped in cold weather.
Ask your pharmacy about winter packaging or express shipping.
I know my Zepbound vials come in a temperature-controlled cooler with ice packs, yet there's enough packaging between the ice and the vials that it never freezes.
Can You Replace Frozen GLP-1s?
If your pen freezes, don’t assume you’re out of luck. Start with your pharmacy — some will replace a pen if it was shipped during freezing weather or if you picked it up recently. Next, check with the drugmaker. Both Novo Nordisk and Eli Lilly have patient support lines and replacement programs, especially if the freezing happened during delivery.
Novo Nordisk (Ozempic, Wegovy, Rybelsus): 1-800-727-6500
Eli Lilly (Mounjaro, Zepbound): 1-833-807-6576
If the freezing was due to storage at home, replacements are less likely, but it’s still worth asking. The key is to call quickly, explain what happened, and have details ready, like your prescription number and the date of purchase. I've seen several success stories for one-time-only issues, but it's not guaranteed.
Bottom line? Make it a priority to put your meds in the refrigerator as soon as possible.
Other Temperature Concerns with GLP-1s
Which GLP-1 drugs can be stored at room temperature, and for how long?
Semaglutide (Ozempic/Wegovy pens): After first use, pens can stay at room temperature (below 86°F) for up to 56 days.
Tirzepatide (Mounjaro/Zepbound pens): Once removed from the fridge, pens can be stored at room temperature (below 86°F) for up to 21 days.
Vials vs pens: Most patients use prefilled pens, but the same general rules apply. Vials should also avoid freezing or excessive heat.
What happens if the GLP-1 gets too hot?
GLP-1s are heat-sensitive. Prolonged exposure above 86°F can cause the active peptide to break down. That means lower potency and weaker results, even if the drug still looks normal. Again, the risk of using overheated GLP-1s, even after getting back to room temperature, is efficacy, not toxic health risks.
How hot is too hot for GLP-1s, and for how long?
Short exposures (like carrying your pen outside on a warm day) usually aren’t a problem.
Sustained heat (hours in a hot car or direct sunlight) is the issue. Once the temperature inside a pen climbs above 86°F for several hours, the drug may degrade.
If it’s been above 90–100°F for any significant time, most manufacturers say the pen should be discarded.
Where is the safest place to store GLP-1 pens in the fridge?
Keep them in the main compartment, not the fridge door. The door is subject to temperature swings every time it opens. A middle shelf in the back of the fridge offers the most consistent cooling. I've read about many people hiding them in the veggie compartment, out of sight from spouses and kids. Both GLP-1 makers say to avoid storing the medication right next to the cooling source inside the fridge, as that could cause freezing or too low temperature exposure.
Can I put my pen or vial back in the fridge after it’s been at room temperature?
This question comes with a few caveats depending on which brand and type you're using. Let's go right to the source.
Novo Nordisk says, "Ozempic® can be used as long as the product has not been exposed to temperatures below 36 °F or above 86 °F. If Ozempic® was exposed to non-refrigerated temperatures (any temperature above 46 °F), the product must be used or discarded within 56 days." Wegovy has the same guidance, except that the expiration date is 30 days.
For Zepbouond, do not put it back in the refrigerator after it has been stored at room temperature. You'll have 21 days for room temperature storage, provided it doesn't get above 86°F or freeze.
What if the medication looks cloudy or discolored?
Semaglutide and tirzepatide solutions should be clear and colorless. If you see cloudiness, particles, or discoloration, do not use it. Call your pharmacy and document the issue with photos.
Should I use ice packs when traveling?
Yes, but never place the pen directly on ice or a freezer pack. Wrap it in a cloth or use an insulated travel case to avoid freezing. Keep it with you in carry-on luggage. Learn more about how to travel with GLP-1s.
Does light exposure affect semaglutide or tirzepatide?
Yes, both drugs should be protected from light because peptides can degrade when exposed for long periods. The concern is mainly direct sunlight or strong artificial light, like a lamp or heat-producing bulb. A few seconds in the refrigerator light when you grab your pen isn’t going to ruin it. What you want to avoid is leaving the pen out on a windowsill, in a hot car, or anywhere sunlight can hit it for hours. The safest bet is to always keep pens in their original packaging or a travel case until use.
There's liquid left after an injection/dose. Can I put this back in the fridge?
It depends on whether you’re using a pen or a vial.
Pens (Ozempic, Wegovy, Mounjaro, Zepbound): These are multi-dose devices. After the first use, pens can be stored in the refrigerator or at room temperature, depending on the product’s instructions. Each pen has an “in-use” time limit (Wegovy and Ozempic: up to 56 days at room temp; Mounjaro and Zepbound: up to 21 days). After that period, any leftover liquid must be discarded.
Vials (tirzepatide only): FDA-approved tirzepatide vials are single-use only. They are intentionally overfilled so you can withdraw the full labeled dose without worrying about air bubbles or dead space in the syringe. Once punctured, any leftover liquid must be discarded and cannot be stored for another injection.
