Can insulin be used if it has been unrefrigerated during a power outage?

According to the FDA, insulin in vials or cartridges (opened or unopened) may be kept at room temperature between 59 and 86 degrees Fahrenheit for up to 28 days and remain effective. Above 86 degrees, effectiveness degrades over time. Do not freeze insulin. If the medication has been exposed to temperatures above the safe range and no replacement is available, the CDC advises using it until a new supply can be obtained, while monitoring blood sugar closely and contacting a doctor as soon as possible.

How long does a refrigerator maintain safe temperature during a power outage?

The FDA states that a refrigerator will keep food cold for about 4 hours if it remains unopened. A closed refrigerator (or freezer) during a power outage may maintain its temperature for at least one day according to FDA guidance on biological products. Keep the door closed as much as possible. An appliance thermometer inside the refrigerator allows you to verify the actual temperature when power is restored.

What medications require refrigeration besides insulin?

Many biologics and specialty medications require refrigeration, including certain injectable medications for rheumatoid arthritis and other immune conditions, some vaccines, certain eye drops, some thyroid and hormone preparations, and some antibiotic liquid formulations. The specific storage requirements vary by product. Always check your medication's label or patient information sheet, and call your pharmacist if you are uncertain whether a specific medication has been compromised after a temperature excursion.

Refrigerated Medications During Outages

The core tension

The safest instruction and the practical one are different.

The safest general rule is straightforward: the CDC states that when the power is out for a day or more, medications that require refrigeration should be discarded unless the label says otherwise.

But insulin is not like a carton of milk. For a person who depends on it, discarding it and having nothing is not the safe option. The CDC also specifies: if a life depends on the refrigerated medication, use it until a new supply is available. This is not an emergency workaround invented on a forum. It is the CDC's own guidance for exactly this situation.

The same tension applies to biologics, certain injectables, and some other specialty medications. Your pharmacist is the right person to advise on your specific medication. This guide gives you the FDA and CDC guidance for insulin specifically, and the general framework for everything else.

Who to call

Your pharmacy is your first call during any medication storage question. Most pharmacies have after-hours and emergency lines. Your prescribing doctor is the second call. The American Diabetes Association emergency line for insulin: 1-800-DIABETES (800-342-2382), Monday through Friday, 9 AM to 7 PM ET.

Insulin specifically

Temperature windows from the FDA.

The FDA provides specific guidance on insulin storage during emergencies. These are the numbers to know before the power goes out.

Refrigerated (ideal)

36 to 46 degrees F

The FDA-recommended storage temperature for all insulin brands. Unopened insulin stored at this temperature maintains potency until the printed expiration date.

Room temperature (usable)

59 to 86 degrees F, up to 28 days

According to the FDA, insulin in vials or manufacturer cartridges (opened or unopened) may be kept at room temperature in this range for up to 28 days and continue to work.

Above 86 degrees F

Effectiveness degrades

The FDA states that insulin loses effectiveness when exposed to extreme temperatures. The longer the exposure, the less effective it becomes. Monitor blood sugar closely and replace as soon as possible.

Additional insulin rules (FDA)

Do not freeze. Insulin that has been frozen should not be used. Keep it away from ice if you are using a cooler, and make sure it does not contact ice directly.
Keep away from direct sunlight and direct heat. Both degrade effectiveness faster than ambient warmth alone.
Insulin pumps: The FDA specifies that insulin in a pump reservoir or tubing should be discarded after 48 hours. Insulin exposed to pump temperatures above 98.6 degrees F should be discarded immediately.
Insulin that was diluted or removed from the original vial (not factory cartridges) should be discarded within two weeks regardless of storage.
When replacement is available: Discard insulin that has been exposed to extreme temperatures and replace with properly stored stock.

Source: FDA, "Information Regarding Insulin Storage and Switching Between Products in an Emergency," fda.gov. Accessed August 2026.

Other refrigerated medications

Insulin is the most common, but not the only one.

Many people who take medications for rheumatoid arthritis, psoriasis, multiple sclerosis, certain cancers, and other conditions take biologics or specialty injectables that also require refrigeration. The guidance is less specific for these than for insulin, because the medications are more varied.

The general framework from the FDA for biological products: most refrigerated products may maintain potency in a closed refrigerator for at least a day during a power outage, unless the internal temperature rises significantly. A thermometer inside the refrigerator allows you to verify actual temperature when power returns.

What to check on your medication

Read the "Storage and Handling" section on the medication label or patient information sheet. The allowable temperature range and maximum unrefrigerated time are stated there.
Call the manufacturer's medical information line (the number is on the package) to ask about your specific situation. Most specialty drug companies have 24-hour lines for exactly this kind of question.
Call your pharmacy. They have access to the drug stability data that is not on the consumer label and can advise on your specific medication and the conditions of your outage.
The FDA advises: discard medical devices that require refrigeration if the temperature has risen above the safe storage temperature. For medications, check the label and call the manufacturer or pharmacy if uncertain.

Common medications that require refrigeration

This is not a complete list. Always check your medication's own label.

Insulin (all types)
Biologic injectables (many rheumatoid arthritis, Crohn's, psoriasis, and similar medications)
Some eye drops (preservative-free formulations in particular)
Some hormone injections and thyroid medications
Some liquid antibiotic formulations (often dispensed for children)
Some MS and cancer treatment injectables

Keeping medications cold

Options when the refrigerator stops.

Each option here buys time. None replaces refrigeration indefinitely. The goal is to keep medication within its allowable temperature range while you obtain a replacement supply or wait for power to return.

Insulated cooler with ice packs

An insulated cooler with ice packs or block ice can maintain safe temperatures for insulin and many biologics for several hours to a day or more, depending on outdoor temperature and how well the cooler is insulated.

Do not let insulin contact ice directly. It can freeze, which destroys it.
Wrap insulin in a cloth or place in a sealed bag before placing near ice.
Keep a thermometer in the cooler to verify temperature.

Wet cloth cooling (short-term)

Wrapping a medication vial in a wet cloth in a shaded area uses evaporative cooling to reduce temperature. This is a short-term measure, not a replacement for ice, and its effectiveness depends entirely on humidity and air movement.

Works best in low humidity and moving air.
Does not work well in humid conditions common during summer outages.
A thermometer is essential to know whether this is working.

Powered cooler or car refrigerator

Small 12-volt coolers and powered car refrigerators can run from a vehicle's power port or a portable power station. They maintain a set temperature without ice and can run for extended periods with the right power source.

Verify the specific temperature range the unit holds before trusting medication to it.
Running from a car engine risks carbon monoxide in enclosed spaces. Use outdoors or in a well-ventilated area.
A portable power station can run a small powered cooler indoors without exhaust risk.

Pharmacy, hospital, or shelter

Pharmacies that remain open during outages usually have backup power. If your medication cannot be kept cold at home, call a local pharmacy to ask whether they can store it temporarily. Emergency shelters designated for people with medical needs often have refrigeration available.

Call ahead. Not all pharmacies store personal medications for customers.
Your local emergency management office can direct you to the nearest medical-needs shelter.

The decision

Use it or discard it?

This decision depends on the specific medication, how long and at what temperature it was stored, whether a replacement is available, and whether not having it is more dangerous than using a potentially degraded supply.

1

Check the temperature and the time

Do you know how long the power was out and what temperature the medication reached? A thermometer in the refrigerator answers this definitively. Without a thermometer, you are estimating, and the conservative answer is to treat the medication as potentially compromised if the outage lasted more than 4 hours (the FDA's guideline for refrigerators maintaining safe temperature while closed).

2

Call your pharmacist or doctor

For any refrigerated specialty medication, call the pharmacy or prescribing doctor before deciding to discard or continue using. They have access to stability data for your specific medication and can advise based on what actually happened rather than the general rule. Most specialty pharmacies have 24-hour emergency lines for exactly this purpose.

3

For insulin: the CDC rule

The CDC states: if a life depends on the refrigerated medication, use it until a new supply is available. Monitor blood sugar closely. Contact your doctor as soon as the emergency is over. Seek medical attention if blood sugar control worsens. Discard and replace as soon as a properly stored supply becomes accessible.

4

Look at the medication

Some degradation is visible. Do not use insulin that appears cloudy, discolored, or has visible particles if it is not supposed to (check the label; some insulins are meant to be cloudy). For clear insulins, any change in appearance is a reason to discard. For other medications, follow the same principle: visible changes in color, consistency, or clarity mean discard.

Plan ahead

Three things to do before the next outage.

Put a thermometer in your refrigerator

A simple appliance thermometer costs a few dollars at a hardware store and answers the most important question after an outage: what temperature did the refrigerator actually reach? Without it, you are guessing. With it, you have a fact. Get one today and put it on the refrigerator shelf where your medications are stored.

Know your medication's room-temperature window

Find the patient information sheet for each refrigerated medication you take. Look for the "Storage and Handling" section. Write down the allowable temperature range and the maximum unrefrigerated time. If you cannot find this on the label, call your pharmacist. Store this information where you will find it during an emergency, not just in your head.

Write down the emergency numbers

Manufacturer's medical information line, your pharmacy's after-hours number, your doctor's emergency line, and the specialty pharmacy number if you use one. These numbers should be on paper, not only in a phone that may have no charge. Keep them in your household binder and in your go-bag alongside the medication itself.

Connected guides

When the refrigerator stops working.