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How long does insulin last once it's been opened?

11 answers | Last updated: Sep 11, 2015
A fellow caregiver asked...

My mother has type 2 diabetes and needs help with her insulin injections. After I open a new bottle, how long does insulin last for, how should I store it, and how do I know whether it's gone bad?


Caring.com User - Theresa Garnero
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Theresa Garnero is clinical nurse manager of Diabetes Services at California Pacific Medical Center in San Francisco.
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Theresa Garnero answered...

As a general rule, most bottles of insulin are good for 28 days once they're opened. Of course, how quickly a person goes through a vial is highly individual. Some See also:
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may go through a bottle in a week or two. Others, on a lower dosage, may not use all the insulin within four weeks. But the drug's stability and potency is only guaranteed for 28 days.

Opened insulin pens typically last 14 days, though some last only 10 days. If you're uncertain, check with your mother's pharmacist to find out how long her insulin should last. When either of you opens a new vial or pen, make a note on the calendar -- and note the date when you'll need to throw out any remaining insulin.

It's best to store an opened bottle of insulin at room temperature, even though manufacturers often recommend refrigeration for opened containers. It's usually less painful to inject insulin when it's at room temperature than when it's cold.

Store unopened insulin vials and pen cartridges in the fridge, though, where they should last until their expiration date. Insulin shouldn't be exposed to extreme temperatures, so don't leave it in the car, next to the stove, in the freezer, or in the bathroom. If the bottle freezes, it must be discarded.

Two typical signs that insulin has gone bad: poor performance and unusual appearance. If your mother is following her treatment plan and her glucose levels stay stubbornly, inexplicably high, her insulin may have lost its potency. Insulin that's cloudy when it's supposed to be clear or that contains particles, crystals, or small clumps is no longer safe or effective and should be discarded.

Even if you or your parent are only mildly concerned that the insulin has gone bad, don't take any chances: Throw the bottle away and open a new one. If the bottle is unopened and the expiration date hasn't passed, you may be able to return it to the pharmacist for an exchange or refund.


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A fellow caregiver answered...

This article was helpful which I'am a diebetic myself and we do keep our insulin in the fridge all the time.


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An anonymous caregiver answered...

that's what my Dr. told me. I check my insulin 5 times a day.


apfelundsie answered...

i cant get my insulin trhough a DR. because i am self pay. I am a type I diabetic. My friend who is also a type I willl give me insulin to inject when she can buy it. She is on a pump(she has insurance) so getting bottles is a little harder. Any who i have a bottle of insulin that expired june 2006 before i use it. Should I? running blood sugars in the 400's and up is a pain. Im tempted because feeling comatose is horrible but im affraid that it will hurt me in some way. Any sujestions?? please respond


dd6f70b1 answered...

the best is to take brown rice well cooked, along whit any other food to minimize the need for heavy dose of insulin says the people who are on the natural food along whit rehabilitation self made programs, in the case of brown rice is better short grain organic, also psalm 91 help the mind to be free from worry, thus helping to get better and not worse Jesus is the reason for the season, love you all now Simoncinni cancer cause and cure is a information available on his site on the web he has good advise too.


antaki answered...

I am on Insulin Humalog (Lispro) and Lantus. I have been keeping them in the refrigerator whil at the same time I have been using them. My dosage of Lispro are early in the morning 7 units, at lunch time 10 units and in the evening 8 units. At bedtime, I use 28 units of Lantus. The lantus insulin lasts for almost 2 months while the Humalog (Lispro) insulin lasts 3 months as long as they are duly refrigerated or kept in a thermocooler . If you require additional information, I may supply you. Antaki


CureMySon answered...

My son is a type 1 diabetic...if you want to use less insulin, and yet stay in range, I have found that eating foods low on the glycemic index require less insulin. Also, your best bet is to weigh and measure your food and match the carbs best you can with insulin to keep from needing a correction after meals. Exercise also helps, as muscles don't need insulin to use glucose for energy. Good luck to those that don't have insurance. Diabetes is expensive!!!


An anonymous caregiver answered...



Markww answered...

Insulin dates and Unopened. Lantis I have used Lantis till bottle was empty 40 days says last for 28 days so I measured my BG and lasted till bottle was empty. SOME GOOD INFO BELOW

NPH is a old insulin comes in three different types can be bought over the counter at Walmart for $24.88 WITHOUT a Script. NPH last 48 days by its paperwork once it has been opened, compared to Lantis. The only draw backs to NPH is that some doctors says shoot it twice cause it is a 12 hour med, But If I am not mistaken it is also a 24 med. That you can read on the paperwork inside the container.

UNOPENED INSULIN REFRIGERATOR -- Best by dates. I have used unopened Insulin Lantis 1.5 yrs after date on container. There was no crystals, NOW IF LANTIS starts to go YELLOW its tossed which has not happened yet. The best thing you can do is use your bottle. If I use a outdated bottle still unopened I just check my BG if it starts to go up I toss the bottle. Hope that helps everyone Mark


An anonymous caregiver answered...

i left a slightly used bottle of Lantis at the beach condo and did not return for 4 months. When i used it, it seemed to work as well as the much newer bottle i was currently using.