How Long Do EpiPens Last?

An expired EpiPen may not be as potent as one that is unexpired. But, in the event of anaphylaxis, an expired EpiPen is probably better than no EpiPen at all. Furthermore, research shows that most epinephrine auto-injectors (EAIs) retain 90% of their drug content for up to 30 months after their expiration date.

An EpiPen is an auto-injecting device that delivers epinephrine to treat severe allergic reactions, including anaphylaxis. Most EpiPens expire 12 to 18 months after the date they are manufactured. Seeing as a two-pack of EpiPens costs at least $600 out-of-pocket, keeping your EpiPens up to date can get pricey.

This article explains how long EpiPens last, along with when you should (and should not) use one that has expired.

How EpiPens Work

Food allergies, particularly to nuts and seafood, can be severe and life-threatening, with more cases of fatal food allergy reactions being reported every year.

The treatment of choice for anaphylaxis from all causes, including as a result of food allergy, is injectable epinephrine. Most cases of fatal anaphylaxis are linked to the lack of, or delay in, the administration of epinephrine.

Epinephrine, also known as adrenaline, is both a neurotransmitter and a hormone. It's also the medication inside of an EpiPen.

During a severe allergic reaction, the immune system releases chemicals called histamines that cause blood pressure to drop and the airways to swell, making it harder to breathe. Some people also experience nausea and vomiting, loss of bladder control, and other symptoms of anaphylaxis.

Upon injecting an EpiPen, epinephrine immediately takes action to:

• Relax the muscles in your airways to help you breathe easier
• Reverse the rapid drop in blood pressure by constricting blood vessels
• Relax the muscles in the stomach, intestines, and bladder

How Long Does an EpiPen Last in Your System?

EpiPens begin to work immediately after they are injected. They also wear off within 20 to 30 minutes, and the allergic reaction can start to come back. For this reason, you should always call 911 after using an EpiPen.

How Long Does an EpiPen Last

Epinephrine auto-injectors, including EpiPen, Twinject, and Avi-Q, have a relatively short shelf life of at least one year. Depending on the manufacturer, the typical epinephrine auto-injector has an expiration date of at least 12 months after its manufacturing date.

Epinephrine degrades relatively quickly, particularly when exposed to light, air, or extreme temperatures. While auto-injector containers are designed to protect epinephrine from the elements, manufacturers still recommended storing them in a dark place at room temperature.

Some studies show that epinephrine stored in an auto-injector may even remain stable and usable for much longer than one year.

How to Read Expiration Dates

An EpiPen expiration date can be found on the auto-injector's label. It is expressed as a set of letters and a number, signifying a month and year. EpiPens always expire on the last day of the month listed. For example, an expiration date that reads "JAN 25" means the EpiPen expires on January 31, 2025.

Can I Use an Expired EpiPen?

Unfortunately, because injectable epinephrine kits are rarely used and are relatively expensive, it's common for people to (knowingly or unknowingly) keep expired epinephrine kits.

With that being said, a person having a severe allergic reaction can use an expired EpiPen, and absolutely should use it if an unexpired EpiPen is not available. Without a doubt, it is far better to use an expired EpiPen than none at all.

According to a study published in The Journal of Allergy and Clinical Immunology, the majority of EAIs retain 100% of their epinephrine content up to six months past the expiration date, and over 90% of epinephrine up to 30 after expiration.

Does this mean that you should purposefully keep your EpiPens for years after they expire? Not if you can help it. While there are minimal risks to using an expired EpiPen, the only way to guarantee your EpiPens have full potency when you need them is to replace them before they expire.

Expiration dates aside, it's important to regularly inspect your EpiPens for signs they have gone bad. The liquid in an EpiPen should be clear. If the liquid is light brown or tea-colored, or has particles in it, then it will not be effective and should be replaced.

Summary

The expiration date for most EpiPens is at least 12 months after its manufacturing date. However, research shows that epinephrine auto-injectors continue to meet FDA requirements for epinephrine potency up to 30 months post-expiration date. While it is better to get new EpiPens before yours expire, in the event of an anaphylactic emergency, expired epinephrine is probably better than no epinephrine at all.

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

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3. Harvard Health Publishing. Is there a way to lower the cost of an EpiPen?.
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5. National Institutes of Health. Unexpected role for the nervous system in anaphylaxis.
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10. American Academy of Allergy Asthma & Immunology. Epinephrine auto-injectors retain high levels of epinephrine years after expiration date, study finds.

• Simons FER, Gu X, Simons KJ. Outdated EpiPen and EpiPen Jr Autoinjectors: Past Their Prime? J Allergy Clin Immunol. 2000;105:1025-30.

By Daniel More, MD
Daniel More, MD, is a board-certified allergist and clinical immunologist. He is an assistant clinical professor at the University of California, San Francisco School of Medicine and formerly practiced at Central Coast Allergy and Asthma in Salinas, California.

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