How to Store Lantus Insulin & How Long It Lasts

Quick answer: Lantus is effective for up to 28 days after being opened and should be stored at room temperature during this time. Yes, Lantus does need to be refrigerated, and it should be kept refrigerated before use to maintain its potency and effectiveness.

Lantus is one of the most prescribed brands of insulin in the United States. It helps millions of people with type 1 and type 2 diabetes manage their blood sugar levels. Lantus is generally administered once a day and is crucial for controlling diabetes in the long run.

It's a long-acting insulin that helps regulate blood sugar levels over an extended period. Unlike fast-acting insulins (also known as bolus insulins), which are typically taken around mealtime to manage immediate spikes in blood sugar, Lantus is a basal insulin that provides a steady, slow insulin release throughout the day and night.

Even though it is so commonly prescribed, many patients may not know how to store their insulin correctly at home, which is crucial for ensuring its effectiveness. Proper storage can help maintain the medication's quality and prevent it from becoming contaminated or degraded.

In this blog, we will discuss how to store your Lantus pens and vials to make sure they stay fully effective and safe for use. We'll also cover common storage mistakes and how to avoid them.

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Does Lantus Need to Be Refrigerated?

Yes, Lantus needs to be refrigerated before it's opened.

Like all types and brands of insulin, Lantus is a biologic drug, meaning it is derived from parts of living cells, and is highly sensitive to temperature. Biologic drugs, such as Lantus, are more likely to break down or become ineffective if exposed to heat, light, or humidity.

Refrigeration helps maintain the stability of the insulin and keeps it potent for the longest possible period.

Before opening, Lantus must be kept in the fridge at temperatures between 36°F and 46°F (2°C to 8°C). Storing it outside this temperature range could cause the insulin to spoil or lose its effectiveness. It's also important to note that while Lantus should be refrigerated, it should never be stored in the freezer, as freezing can permanently damage the insulin.

Lantus Storage Instructions

Proper storage is essential for keeping your Lantus in optimal condition. Let's break down the specifics to ensure that your insulin stays effective.

Proper Refrigeration Before Opening

Before you open a new Lantus pen or vial, it must be stored at the proper temperature in the fridge.

✅ Keep unopened pens/vials in the fridge: Store in a compartment between 36°F and 46°F (2°C to 8°C).

✅ Avoid freezing: Do not store in the freezer.

✅ Store away from the freezer compartment: Ensure that Lantus does not come in contact with freezing temperatures in the fridge.

Lantus Storage After Opening

Once you open a Lantus pen or vial, it's no longer safe to store it in the fridge.

✅ Store at room temperature: Once opened, keep the Lantus pen or vial at a temperature below 86°F (30°C).

✅ Avoid sunlight and heat: Never store Lantus in direct sunlight or near heat sources (like stoves or radiators).

✅ Use within 28 days: After opening, discard any leftover insulin after 28 days to ensure effectiveness.

💡 Pro tip: If you don't think you will use the entire vial or pen within 28 days, it's a good idea to store an unopened backup in the fridge for future use.

How Long Does Lantus Last?

Lantus has two different expiration timelines depending on whether it's unopened or opened. Understanding these timelines will help you ensure that you're using the insulin while it's still effective.

Lantus Expiration When Unopened

Unopened Lantus, when stored in the fridge, will remain effective until the expiration date printed on the container. The expiration date is typically about one year after purchase, but it can vary depending on when the product was manufactured.

It's essential to check the expiration date on the packaging and avoid using the insulin after this date, as expired Lantus may not effectively control blood sugar and could cause unwanted health complications.

To maximize the shelf life of unopened Lantus, always keep it refrigerated until you're ready to use it. If you have multiple pens or vials, be sure to rotate your stock and use the oldest one first.

Lantus Expiration Once Opened

Once Lantus is opened and exposed to room temperature, it has a shelf life of 28 days. After 28 days, it's no longer safe to use, even if insulin remains in the pen or vial. This is because, after this period, Lantus begins to degrade, and its potency is compromised.

It's essential to keep track of when you open a new pen or vial, especially if you're using it intermittently or are prone to forgetting the exact date. A simple way to remember is to write the opening date on the pen or vial label, so you can quickly check when it's time to discard it.

Can You Take Lantus After the Expiration Date?

No, you should never take Lantus after the expiration date has passed. Expired insulin is ineffective, and using it could lead to poorly controlled blood sugar levels, potentially causing severe complications such as diabetic ketoacidosis.

How Long Can Lantus Be Unrefrigerated?

Can You Put Lantus Back in the Fridge After Opening?

No, you should never put Lantus back in the fridge after it has been taken out and reached room temperature.

Once the insulin has been exposed to warmer temperatures, the "cold chain" is broken, and putting it back in the fridge won't extend its shelf life. It's best to keep it at room temperature (below 86°F / 30°C) for up to 28 days and dispose of it if it's not used within that timeframe.

What Happens if Lantus Gets Too Warm?

While Lantus can remain unrefrigerated for up to 28 days, it is essential to protect it from exposure to temperatures above 86°F (30°C).

If Lantus is left in a hot car, near a stove, or in direct sunlight, the insulin can go bad and lose its effectiveness. This could result in ineffective blood sugar control, leading to hyperglycemia (high blood sugar levels) or even diabetic ketoacidosis, a potentially life-threatening condition.

If you suspect that your Lantus has been exposed to excessive heat, it's safest to discard it and use a new, properly stored vial or pen.

How to Know If Your Lantus Has Gone Bad

Even if your Lantus is within the 28-day window after opening, it's crucial to inspect the insulin for any changes in appearance. Lantus should be clear and colorless. If you notice any cloudiness, discoloration, particles, or clumps inside the pen or vial, discard it immediately, as these are signs that the insulin has gone bad.

Final Tips: Safe and Effective Lantus Storage

Proper storage of your Lantus insulin is key to ensuring its effectiveness and longevity.

By following the right guidelines for refrigeration and room temperature storage, you can confidently manage your diabetes without worrying about spoiled or degraded insulin.

Key Takeaways:

Now that we've covered the essentials of storing Lantus, let's review the key takeaways for quick reference:

🧊 Keep It Cold: Lantus must be refrigerated before opening to maintain its effectiveness. Once opened, it can stay at room temperature for up to 28 days.

🕒 28 Days Max: After opening, Lantus lasts only 28 days at room temperature. Do not use it after that period, even if it hasn't been fully used.

🚫 No Freezing: Never freeze Lantus, as it can damage the insulin and make it ineffective.

👀 Check for Changes: Always inspect Lantus for any changes in appearance, such as cloudiness or discoloration. If it looks different, discard it to avoid using ineffective insulin.

We'd love to hear from you!

💬 Do you have any questions about storing Lantus or tips for keeping your insulin safe? Share your experiences or ask a question in the comment section below!

📆 Article Update History:

✅ Updated: April 17, 2025

Originally Published: December 01, 2022

December 01, 2022

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Comments

4AllFamily Customer Service said:

Dear Helen,

It’s concerning to hear about the delivery conditions of your husband’s Lantus insulin. Given that Lantus is only effective for 28 days if not refrigerated, the key concern is how long it was unrefrigerated and if it ever exceeded the temperature limit of 30°C.

I recommend contacting the pharmacy to explain the situation and express your concerns, asking for a replacement due to the uncertainty of the medication’s stability. If the pharmacy does not provide a satisfactory response, consider reaching out directly to the manufacturer to report the issue and seek further advice. It’s crucial to ensure the insulin is effective and safe for your husband’s use.

I hope this issue solves promptly,
Warm regards,
4AllFamily

Helen said:

My husband’s Lantus(3 months supply) has just been delivered by the pharmacy (they say it was in a cool bag in a car). It was in a paper bag on top of other medications and I noticed it wasn’t even cool, so I used our medical fridge temperature probe to check the temperature. It was 26°C. The pharmacy said it wasn’t a problem and told him to put it in the fridge where it has just got back down to 8 degrees after 40 minutes or so. I don’t know how long the insulin was out of the fridge but it was delivered at 4pm so could have been out since the morning. Will it have been degraded?