Does Insulin Need to Be Refrigerated? Essential Users Tips for Proper Insulin Storage!

Quick answer: Insulin needs to be refrigerated between 36°F and 46°F (2°C and 8°C) before opening to maintain its effectiveness. Once opened, it can stay at room temperature (below 77°F or 25°C) for up to 28 days. Proper storage is essential to ensure insulin remains safe and effective.

While insulin is a life-saving treatment for people with diabetes, managing its use, especially when it comes to refrigeration and storage, can be challenging.

Surprisingly, many people with diabetes are unaware of how to store their insulin correctly. Insulin that's left unrefrigerated for too long or stored improperly can lose potency, leading to uncontrolled blood sugar and potentially serious complications.

As a general rule, unopened insulin should be refrigerated between 36°F and 46°F (2°C and 8°C). After opening, it can be kept at room temperature, below 77°F (25°C), for up to a month, but there's more to storing insulin than just keeping it cool.

The following article will answer all your questions about insulin refrigeration and storage to help keep your pens and vials safe and effective.

Does insulin need to be refrigerated?

Insulin is a protein-based hormone sensitive to temperature fluctuations. Regardless of the type, brand, or container, manufacturers recommend storing unopened insulin in a refrigerator at temperatures between 36°F and 46°F (2°C to 8°C) to preserve its potency.

Refrigerating insulin before use helps to:

✅ Preserve insulin potency: Insulin is a delicate protein that can degrade when exposed to heat. Keeping it refrigerated between 36°F and 46°F (2°C and 8°C) helps preserve its molecular structure, ensuring it remains effective in managing blood glucose levels.

✅ Extend shelf life: When stored properly in the refrigerator, insulin retains its full potency until the expiration date printed on the packaging. Exposure to warmer temperatures can accelerate insulin's breakdown, reducing its shelf life and requiring more frequent replacements.

✅ Prevent bacterial growth: Warm environments can promote bacterial contamination in biologic medications like insulin. Refrigeration reduces this risk, helping ensure that the insulin remains safe and sterile for use.

Exposure to temperatures outside this range can degrade insulin, rendering it less effective. Be careful that your fridge isn't set to temperatures below 36°F (2°C) to prevent insulin from freezing, which would render it ineffective, too!

💡 Pro tip: It's a good practice to regularly check and monitor your fridge temperature. Using tools like a smart thermometer that alerts you when the temperature deviates from the set range, in case of a power outage for example, can help ensure that your insulin is always stored at the optimal temperature.

Are you a visual learner? Here's a helpful video on insulin refrigeration:

Related article: How to Store Insulin Without Refrigeration? Practical Tips from a Type 1 Diabetic!

How long does insulin last in the fridge?

When properly stored in the refrigerator, unopened insulin pens and vials remains effective until the expiration date printed on the packaging or container.

Each insulin vial, pen, or cartridge includes an official expiration date provided by the manufacturer. In most cases, the refrigerated shelf life of unopened insulin is about one year from the purchase date, but always double-check the label.

If unsure, your pharmacist can help clarify the exact expiration date.

It's important to understand that insulin has two expiration timelines you should track:

• 📅 The official expiration date: This is printed on the insulin packaging and applies as long as the insulin remains unopened and refrigerated.
• 📅 The "in-use" expiration date: Once insulin is opened or removed from the refrigerator, it typically lasts for 30 days, depending on the brand and type.

Even if unopened insulin has been refrigerated the entire time, it should never be used past its printed expiration date. After this point, insulin becomes chemically unstable, less effective, and potentially unsafe. Using expired insulin can result in elevated blood sugar levels and increase the risk of serious diabetes complications.

To stay safe, keep track of the official expiration date AND the date you first opened or removed your insulin from the fridge.

Related article: Insulin Storage: 10 Common Mistakes to Avoid When Storing Your Insulin Pens and Vials

How long can insulin be out of the fridge?

While the general guideline is that insulin can stay unrefrigerated for about one month, the exact length of time it is good out of the fridge varies based on the brand and type of insulin prescribed.

Below is a list of how long popular insulin brands are good out of the fridge, according to their respective manufacturer:

• Lantus (insulin glargine): up to 28 days.
• Novolog (insulin aspart): up to 28 days.
• Humalog (insulin lispro): up to 28 days.
• Humulin N (insulin NPH): up to 31 days.
• Humulin R (insulin regular): up to 31 days.
• Apidra (insulin glulisine): up to 28 days.
• Novolin N (insulin NPH): up to 42 days.
• Novolin R (insulin regular): up to 42 days.
• Levemir (insulin detemir, discontinued in the US): up to 42 days.
• Tresiba (insulin degludec): up to 56 days.
• Toujeo (insulin glargine): up to 42 days.
• Basaglar (insulin glargine): up to 28 days.
• Fiasp (insulin aspart): up to 28 days.
• Admelog (insulin lispro): to 28 days.
• NovoRapid (insulin aspart): up to 4 weeks.
• Lyumjev (insulin lispro-aabc): up to 28 days.
• NovoMix (insulin aspart and insulin aspart protamine): up to 4 weeks.
• Humulin 70/30 (premixed insulin): up to 31 days.
• Novolin 70/30 (premixed insulin): up to 6 weeks.
• Humalog Mix 75/25 (premixed insulin): up to 10 days.
• Semglee (biosimilar to Lantus): up to 28 days.

Always consult the specific storage instructions provided with your insulin. If you have doubts, speak with your healthcare provider or pharmacist to determine the exact shelf life of your insulin when not refrigerated.

Related article: Can You Put Insulin Back in the Fridge After It's Been at Room Temperature?

The importance of proper temperature for insulin storage

Proper temperature is crucial for insulin storage because insulin is a heat-sensitive protein that can break down when exposed to heat or freezing temperatures.

When storing insulin, make sure it is kept within the recommended temperature ranges:

✅ Refrigerated Storage: 36°F to 46°F (2°C to 8°C).

✅ Room Temperature Storage: below 77°F (25°C)

Maintaining the right temperature ensures insulin remains effective, safe to use, and capable of properly regulating blood sugar levels.

Factors Affecting Insulin Stability

• Temperature: Exposure to temperatures above 86°F (30°C) can degrade insulin.
• Light: Direct sunlight can break down insulin molecules.
• Time: Even at optimal temperatures, insulin loses potency over time.

If insulin is left out for 12 hours, is it still safe?

Leaving insulin out of the refrigerator for 12 hours is generally acceptable if the ambient temperature remains below 77°F (25°C).

However, if the environment is warmer, the insulin's effectiveness may be compromised. Always inspect insulin for changes in appearance and consult a healthcare provider if unsure.

Related article: Can Insulin Go Bad? How to Identify Spoiled Insulin, Avoid Risks, and Store It Properly

Is it safe to use insulin that's been out of the fridge for too long?

⚠️ No, it is not safe to use insulin that has been left out of the fridge for too long, especially if it's been unrefrigerated for more than 28 days.

While using degraded insulin may not cause immediate harm, its effectiveness can be significantly reduced, putting your health at serious risk.

Think of it like this: insulin that's lost its potency is like injecting water; it won't do much to lower your blood sugar levels. Without properly working insulin, your blood glucose can rise unchecked, leading to hyperglycemia.

In people with type 1 diabetes, consistently high blood sugar from ineffective insulin can quickly lead to diabetic ketoacidosis (DKA), a dangerous and potentially life-threatening condition. Even in type 2 diabetes, poor blood sugar control over time increases the risk of complications affecting the heart, kidneys, eyes, and nerves.

What Happens If Insulin Gets Warm?

When insulin is exposed to temperatures above the recommended range, it can quickly lose its effectiveness. Here's what can happen:

❌ Degradation of insulin potency. High heat can break down the delicate proteins in insulin, causing protein denaturation. This means the insulin's molecular structure changes, making it less effective at managing blood sugar.

❌ Reduced Blood Sugar Control. As insulin potency decreases, your body may not respond to it as expected. This can lead to poor blood sugar control, resulting in high blood glucose levels (hyperglycemia) and increasing the risk of complications over time.

❌ Visible Signs of Spoilage. If insulin has been compromised by heat, it may look cloudy, discolored, or contain clumps or particles. These changes are visual indicators that the insulin is no longer safe or effective to use.

You can take the following preventive measures to make sure your insulin stays safe and effective for as long as possible:

• Avoid Direct Heat: Keep insulin away from heaters, stoves, and direct sunlight.
• Use Insulin Coolers: When traveling, use cooling pouches or mini fridges for insulin to maintain temperature.
• Monitor Storage Conditions: Regularly check the storage environment's temperature.

Related article: Insulin and Heat: How to Keep Your Supplies Safe in High Temperatures!

Best practices for insulin storage after opening

Once insulin is opened or removed from the refrigerator, it should be stored at room temperature below 77°F (25°C) and used within 28 days. Following proper storage guidelines ensures insulin remains safe and effective throughout its use.

✅ Best Practices

• Label the opening date: As soon as you open a new vial, pen, or cartridge, write the date on it. This helps you track how long it's been in use and ensures you don't accidentally use insulin that's past its usability window.
• Avoid freezing: Never store insulin near the freezer compartment or allow it to freeze. Frozen insulin becomes ineffective, even if it later thaws, and should be discarded immediately.
• Keep a consistent temperature: Try to store your insulin in a place with a stable, cool temperature, away from heat sources like stoves, windows, or direct sunlight. Frequent temperature fluctuations can degrade insulin faster.
• Use insulin coolers when traveling: When you're on the go, carry your insulin pens and vials in proper insulin cooling cases. This helps protect it from overheating and light exposure.

🗑️ Disposal Guidelines

• Follow the 28-Day rule: Most insulin products are only stable for 28 days after opening. Regardless of how much insulin is left, it's best to discard it after this period to avoid using degraded medication.
• Use a sharps container: Dispose of used insulin pens or syringes in a proper FDA-cleared sharps disposal container to keep yourself and others safe from accidental needle sticks.

Related article: The Ultimate Guide to Traveling with Insulin: How to Keep It Refrigerated and Cool on the Go

Final thoughts on how to store insulin properly

Unopened insulin needs to be refrigerated to maintain its potency until expiration. Once it's opened, insulin can safely be stored at room temperature below 77°F (25°C), as long as it's used within its effective timeframe.

If you're ever in doubt about whether your insulin is still good, remember: when in doubt, throw it out. It's always safer to replace questionable insulin than risk poor blood sugar control or a medical emergency.

Related article: Can You Inject Insulin Cold Straight From the Fridge?

Key Take Aways:

❄️ Refrigerate unopened insulin: Insulin should be refrigerated until it's opened to maintain its potency.

🌡️ Room temperature after opening: Once opened, insulin can be stored at room temperature (up to 77°F/25°C) for up to 28 days, or longer depending on the type.

⏳ Be aware of expiration dates: Always use opened insulin within the recommended timeframe for optimal effectiveness. Don't risk poor control by using expired insulin.

🛑 When in doubt, throw it out: If you're ever unsure whether your insulin is still effective, it's better to replace it than risk an emergency due to degraded insulin.

We'd Love to Hear From You!

💬  We hope you found this article helpful and feel more confident in storing your insulin correctly, whether at home or while traveling. We'd love to hear from you! If you have any questions, personal experiences, or additional tips about insulin refrigeration and storage, please share them in the comments below. Your insights could be invaluable to others!

📆 Article Update History:

✅ Updated: May 1, 2025

✅ Updated: May 21, 2024

Originally Published: December 14, 2022