Quick answer: Never freeze your Zepbound pens. If tirzepatide freezes, even briefly, it can become unsafe and ineffective. Never inject a pen that may have been frozen, even if it looks normal.
Tirzepatide, commonly known under brand names like Zepbound and Mounjaro, is a once-weekly injectable medication used to treat Type 2 diabetes and aid in weight loss.
Because it's a temperature-sensitive injectable, many people are understandably concerned about what happens if it's stored improperly, especially in extreme cold or warm temperatures.
Whether you've accidentally left your Zepbound pen in the freezer or it arrived in the mail during a cold winter day, it's essential to understand how freezing affects tirzepatide.
In this article, we'll explore the consequences of freezing tirzepatide, how to know if it's still safe to use, and what to do if you suspect your medication was exposed to extreme cold.
Can you freeze tirzepatide (Zepbound & Mounjaro)?
You should never freeze tirzepatide or use it after it has been frozen.
It should always be kept between 36°F and 46°F (2°C to 8°C). If needed, it can be stored at room temperature (below 86°F or 30°C) for up to 21 days.
Here are a few ways to protect your supply:
✅ Store pens in the middle of the fridge, not near the back where temperatures are colder.
✅ When traveling, use a medication travel case with temperature control that prevents freezing if in direct contact with the cooling element.
❌ Avoid ice packs that come into direct contact with your Zepbound or Mounjaro pens.
These small precautions go a long way in preventing costly losses and treatment interruptions.
Related article: The Do’s and Don’ts of Tirzepatide Refrigeration and Storage
What happens if tirzepatide freezes?
If tirzepatide is exposed to freezing temperatures, its chemical structure can break down. This reduces its effectiveness and can even make it unsafe to use. Tirzepatide cannot be thawed and reused once frozen, it must be thrown away.
Why? Because Tirzepatide is a biological drug, freezing can denature the delicate proteins in the medication. Even if the pen still looks normal, the drug may not work as intended.
Never inject tirzepatide that has been frozen, even briefly.
To prevent storage mishaps from happening in the first place, it's important to know exactly how to store medications with tirzepatide correctly.
Check out our complete Tirzepatide refrigeration guide for everything you need to know about keeping your medications with this active ingredient safe and effective.
What to do if your tirzepatide was exposed to freezing temperatures
If you suspect your tirzepatide pen has frozen, follow these steps:
- Don't use it. Even if it looks fine, the damage might not be visible.
- Inspect for changes. Look for particles, cloudiness, or cracks.
- Check how it was stored. Was it near a freezer vent? Left outside?
- Contact your pharmacist or healthcare provider. They can help determine next steps.
Related article: Freezing Mounjaro: Risks and Prevention Tips
Can you freeze Zepbound?
Zepbound, a branded version of tirzepatide used for weight loss, is just as sensitive to cold.
Just like tirzepatide in general, you cannot freeze Zepbound. Even temporary exposure to freezing temperatures (like being left outside or in a car) can make it ineffective.
What happens if Zepbound freezes?
When Zepbound freezes, it may:
- Become cloudy or develop floating particles
- Lose its ability to regulate blood sugar or support weight loss
- Cause discomfort at the injection site
- Pose safety risks if used after thawing
Even minor freezing can compromise the integrity of the medication. If you left your Zepbound pen in the car overnight during winter or it arrived in cold packaging, don't take chances.
When in doubt, we always recommend reaching out to a healthcare provider to determine if a replacement is needed.
Related article: How to Travel Safely with Zepbound: TSA Rules, Storage Tips, and Keeping Your Injections Cool on the Go
Tips for preventing tirzepatide (Zepbound) freezing
Tirzepatide-based medications like Zepbound are temperature-sensitive and must be handled with care, especially in colder months.
Here are some practical tips to help you avoid accidental freezing and protect your medication's effectiveness:
✅ Monitor your fridge temperature
Make sure your refrigerator is set between 36°F to 46°F (2°C to 8°C), the safe range for storing tirzepatide. If you don't already have one, consider using a refrigerator thermometer to make sure the internal temperature stays consistent and doesn't dip too low.
❄️ Avoid storing pens near the freezer compartment
Never place Zepbound pens near the freezer box or at the back of the fridge. The coldest areas, often at the rear or side vents, can accidentally expose your pen to freezing temperatures.
Store it in the middle shelf, ideally in a container or designated medication drawer.
🚗 Don't leave your medication in the car overnight
Even a few hours in a cold vehicle can ruin your tirzepatide.
Always bring your medication indoors and avoid storing it in places where temperatures are uncontrolled or can drop below freezing.
🧥 Keep it close in cold weather
When you're out and about in chilly conditions, place your pen in an inside coat pocket, close to your body. Your natural body heat can help maintain a safe temperature and prevent freezing during transport.
🧳 Use a travel case
If you're traveling or need to keep your medication cool on the go, invest in a temperature-regulated travel case designed for insulin or biologic meds.
4AllFamily offers a wide range of products designed to keep your medication safe in extreme temperatures. Our newest travel case, the RxCoolers Max has a dual functionality, warming up when it gets too cold and cooling down when it gets too hot!
Related article: How Long Can Zepbound Be Out of the Fridge Without Going Bad?
Final thoughts on preventing your tirzepatide from freezing
Freezing can silently destroy your tirzepatide injections, even without any visible signs.
Because it's a temperature-sensitive biologic, protecting your Zepbound and Mounjaro pens from extreme cold is essential. With just a few simple precautions, you can protect your medication, your health, and your peace of mind.
📌 Key Takeaways:
💉 Never use a frozen pen: Tirzepatide becomes unsafe and ineffective once frozen-always discard it.
❄️ Store smart in the fridge: Keep pens in the middle shelf, away from cold spots near the freezer.
🚗 Cold weather = caution: Never leave tirzepatide in your car or near exterior doors in winter.
🧊 Use anti-Freeze travel gear: Choose medical cooler bags with anti-freeze biogel packs for peace of mind while traveling.
We'd Love to Hear From You!
💬 Have you ever had to deal with a frozen Zepbound pen? Do you have any fridge storage hacks or travel tips to keep your tirzepatide safe? Share your experience or ask us a question in the comments!
