Lantus is one of the most prescribed brands of insulin in the United States. But studies have shown that most patients don’t know how to store their medicine correctly at home.

Don’t be one of them. Optimal refrigeration and adequate storage are what guarantee that Lantus stays fully effective for the longest. Ultimately, your diabetes management depends on it.

Learn here how to refrigerate, store, and keep your Lantus pens or vials once back from the pharmacy.

4AllFamily Travel Coolers for Insulin, Lantus, Novolog, Humalog, Fiasp, Levemir, HumulinKeep Lantus Refrigerated at All Times with 4AllFamily's Travel Coolers!

What is Lantus? 

Lantus is a long-acting synthetic insulin used to treat people with type 1 or type 2 diabetes. It helps lower blood sugar levels and keep them in the normal range to prevent diabetes-related complications. 

Long-acting insulins, also called basal insulins, have a prolonged duration of action and stay in the bloodstream for 24 hours. As opposed to fast-acting insulins (bolus insulins), they're usually taken once daily and help manage blood glucose between meals and overnight.

Lantus is administered via subcutaneous injections and is available in different formats like the Solostar auto-injectable pens, vials, or cartridges.

Related articleA Beginner's Guide to Basal and Bolus Insulin.

Does Lantus need to be refrigerated?

Yes, Lantus need to be refrigerated. Like all types and brands of insulin, Lantus is a biological drug. More specifically, long-acting insulins like Lantus, Basaglar, and Toujeo contain insulin glargine as their active ingredient.

Biologic drugs are made from parts of living cells (plants, animals, or humans). Therefore, they are highly sensitive to temperature and storage conditions. As a result, biologics like Lantus can quickly spoil, go bad, or get contaminated when exposed to high temperatures, luminosity, or humidity.

That’s why Lantus must be refrigerated before opening and is only good for a limited time once taken out of the fridge. 

Related article: Does Insulin Really Need to Be Refrigerated and How to Store Your Pens and Vials Correctly?

Lantus storage instructions

According to Sanofi, the manufacturer of Lantus, this insulin must be stored in the fridge before opening (36°F to 46°F / 2°C to 8°C ) until the expiration date labeled on the contained. 

Once open or out of the fridge for more than a few hours, Lantus must be kept at room temperature (below 86°F / 30°C) and is only good for 28 days.

When kept inside the fridge, ensure your pens or vials are not in direct contact with the freezer compartment. Frozen Lantus isn't safe for use, even if it has thawed afterward.

Additionally, you must pay attention to avoid exposing Lantus to direct light for prolonged periods of time.

How long does Lantus last?

Like any insulin, Lantus has two different expiration dates. The first one is the one labeled on the container by the manufacturer. Lantus lasts until this official expiration date if kept in the refrigerator. It’s usually about one year after the purchase date.

The second expiration date is not set but occurs 28 days after you've opened your Lantus pen or vial for the first time or left it out of the fridge for a few hours.

Related article: How to Store Novolog Insulin Correctly?

How long can Lantus be unrefrigerated?

Once left out of the fridge, Lantus has a limited shelf life and is only safe for 28 days. Past that time, laboratory and clinical tests have shown that it starts degrading and losing efficiency.

So, Lantus can be unrefrigerated for a maximum of 28 days. It should be protected from high heat and direct light during that time.

Can you put Lantus back in the fridge once opened? 

No. According to Sanofi, you should not put Lantus back in the fridge after opening it. Once it has reached room temperature and the cold chain is broken, putting it back in the fridge won't prolong its shelf life. Besides, temperature fluctuations aren't good for biological drugs either.

Related article: Humalog Insulin, Storage Instructions and Best Practices!

How long is Lantus good for after opening?

Lantus is good for a maximum of 28 days after opening or until its expiration date if it occurs first.

Once Lantus has expired, you must throw your pen or vial away, even if it still has insulin inside. Using expired insulin or insulin that has gone bad can be dangerous for your health. So do not take any chance. 

Related article: Does Levemir Need to Be Refrigerated and How Long is it Good For?

What happens if Lantus is not refrigerated?

When not refrigerated, Lantus becomes unstable and starts degrading gradually. Like other insulins and biological drugs, Lantus stability at room temperature is limited. As said above, it's only guaranteed to be safe for use and fully effective for 28 days when not refrigerated.

Insulin is a protein, and, like any protein, its exposure to light and high temperatures can spoil it.That's why the Lantus Solostar pen cap is opaque. It protects the medication from light.

What if Lantus gets warm?

While Lantus can stay unrefrigerated for 28 days without risking deterioration, it should still be protected from high temperatures.

Exposure to temperatures above 86°F / 30°C, even briefly, can quickly make Lantus go bad and lose its potency, which could ultimately cause severe consequences for your health, including high blood sugar levels and ketoacidosis. 

During 28 days after opening, protect your Lantus pens and vials from heat. Never leave them near a heat source (stove, chimney, etc.). Do not leave them in the car on a sunny day, and use an insulin cooler whenever outside temperatures are above 86°F / 30°C.

When in doubt, and if you think your Lantus got warmer than that, throw it away immediately and get a new one from the fridge.

Related article: A Step-by-Step Guide to Using Insulin Pens for Injection.

How to keep Lantus cool while traveling?

Keeping insulin cool while traveling or away from home is one of the biggest concerns of people with insulin-dependent diabetes.

Whether on holiday or not, there are numerous situations where your Lantus pen may be exposed to high temperatures, especially if you live in or travel to places where it frequently gets above 86°F/ 30°C. 

Most diabetes patients choose to use a portable insulin cooler like the ones from 4AllFamily. Our team of experts designs medical-grade travel coolers for people whose life depends on refrigerated medications.

4AllFamily Travel Coolers for Insulin and Diabetes Injections

Our products range from pocket-size insulin cooling cases to high-performing mini travel fridges. Depending on your needs, travel habits, and lifestyle, they can function with USB power or simple freeze packs. They're all TSA-approved to keep your insulin cool even while on the plane.


Related article: How to Keep Insulin Cool While Traveling?

How to tell if your Lantus pens or vials have gone bad?

Like most insulins, glargine insulin, such as Lantus, is a clear, colorless, water-like liquid. Visual inspection may help tell if your Lantus has gone bad. Any change of color, cloudiness, clumps, strings or frost inside indicates that Lantus isn't suitable for use. However, bad Lantus isn’t always visible.

Unexplained high blood sugar levels may also indicate your Lantus has gone bad. In any case, when in doubt, immediately throw your in-use pen or vial away and get a new one from the fridge. Do not take any chances.

Related articleClear vs. Cloudy Insulin, Why it Matters!

What are the risks of using bad Lantus?

The main risk of using bad Lantus is prolonged hyperglycemia (high blood glucose). If your Lantus has expired, whether because of a past expiration date, exposure to high temperatures, or being unrefrigerated for more than 28 days, it may have lost its efficiency and become useless.

Injecting bad Lantus is like injecting water. While it won’t make you sick, it won’t lower your blood sugar. Ultimately, this could cause diabetic ketoacidosis, a life-threatening diabetes complication.

We hope we've answered your questions about refrigerating and storing Lantus. If not, please place your comment below! 

December 01, 2022


4AllFamily Customer Care Team said:

Dear Margaret,
Thank you for your comment. According to Sanofi, the manufacturer of Lantus, you should not put the injector pen back in the fridge after each injection, as this would cause too many temperature fluctuations.
The best practice is to store your unopened Lantus pens in the refrigerator, but once you’ve used a pen for the first time, keep it out of the fridge (at room temperature) between each injection and for about 28 days.
I hope I´ve answered your question. Don’t hesitate to reach out to your pharmacist or doctor too,
Warm regards,

Margaret said:

Appreciate your help about this. I give myself one injection in the morning. I take Lantus out of refrigerator for about 15 minutes as I prepare checking bloodwork. Give injection the put back in frig. Is this ok?
I am new to insulin only 2 days use. I was literally given no directions on any of this. I am legally blind and slowly learning on iPad from the internet. All information is greatly appreciated.

4AllFamily Customer Care Team said:

Dear John,
According to Sanofi, you should not put Lantus back in the fridge after opening it. Once it has reached room temperature and the cold chain is broken, putting it back in the fridge won’t prolong its shelf life. Besides, temperature fluctuations could deteriorate the medicine quicker.
You’re not in trouble, but in the future, try to follow the manufacturer’s instructions as much as possible!
Warm regards,

John said:

I have been using Lantus Solostar for 3 months. It helps a lot. I have been putting it back in fridge after each use. Am I in trouble? I just found out, you are supposed to keep it out after first use.

4AllFamily Customer Care Team said:

Dear Rick,
According to the manufacturer, Lantus should not be put back in the fridge once open, mainly because of temperature fluctuations that could deteriorate the insulin.
However, it’s common practice to do so when there’s no better option.
I would recommend getting a cooler though, something like the Companion Cooling Bag that can keep your open insulin pens at room temperature when it’s hot outside or in your camper van.(
Best regards,
4AllFamily Customer Care Team

rick said:

I just received the lantus solo pen,can i leave the solo star pen in the refrigerator after opening due to the temperatures in my camper get up to 90 degrees

4AllFamily Customer Care Team said:

Hi Jennifer,
Lantus contains the active drug insulin glargine, which is a biological product made from parts of living cells. It’s a hormone protein. As such, and like any protein, exposure to light and high temperature can spoil it.
Think of it as meat: once the cold chain has been broken, the degradation process begins and the time you have left to eat it is limited.
The same happens with Lantus and other insulins. Once you’ve taken it out of the fridge and disrupted the cold chain, it begins its degradation. Fortunately, degradation happens slowly and gradually, and laboratory tests have shown that Lantus stays fully effective for up to 28 days when unrefrigerated (if not exposed to high temperatures).
I hope I’ve answered your question,
All the best,
4AllFamily Customer Care Team

Jennifer waithe said:

Grateful if you could explain just why lantus should not be stired in the fridge while in use.
Is it due to oxidation that occurs once the pen has been punctured by the needle,,?

4AllFamily Customer Care Team said:

Hi Timothy,
If you do not have access to a fridge, you do need a portable solution to keep your stocks of Lantus refrigerated. Lantus can be only left unrefrigerated for up to 28 days.
If you have access to household or USB power, we recommend using our big-size insulin cooler:
When plugged in to a power source, it keeps insulin refrigerated for an unlimited time. It can hold up to 7 Lantus pens. Should you need to buy several units, please reach out at so we can help you.
All the best,
4AllFamily Customer Care Team

Timothy said:

I live in the country side and have no access to a fridge. I have to buy 2 to 3 months supply of Lantus insulin. How for i store the insulin for later use?

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