Ever since I keep my insulin out the fridge this happens

I had my insulins always in the fridge before I changed to keeping them out when in use. I thought that the action of the insulin was better keeping it out the fridge. Then I discovered that towards the end of the month when I always take new insulins the insulin I kept out was not performing properly, giving me many sudden highs. When I changed to the new bottles there was a notable difference in the readings coming down. This is a bit of a problem now. I can change a little earlier, maybe when I notice the higher readings, it is time to change the insulins.
Do any of you have the same experience? Or is this a JB special?

JB. (The sun is shining out there!)

I am going to say I think this is a JB special…lol…I have never heard of insulin not needing to be refrigerated unless it was in the pen form and it was already used once. If it was just plain on insulin in a vial I think you were using it wrong to being with. I am happy to hear however that you discovered when the insulin works best for you. :slight_smile:

I always keep my stash in the fridge and agree that it works better, particularly @ the end of a bottle. I think it gets a bit fried, even at reasonable room temperatures. When I did MDI, I’d save some empty bottles to use for portable purposes on hot days.

my dtr is on a pump and we use vials of insulin and must carry one with us all the time (at room temp)…not to mention the insulin in the pump is obviously at room temp for the 3 day duration of the pump and it “seems” to work fine but there ARE times when I wonder if at the end of the bottle is it working as well as when it was fresh…

Hi JB. My Apidra absolutely has to be kept in the fridge after opening. I transport both my Apidra vial and Levemir pen in an insulated bag with ice, three seasons of the year. Losing a pen or a vial after two weeks of use drives me crazy, but it happens. Good luck.

Johnben, you are SPECIAL!!

I keep mine in the fridge and use about a bottle a month. I’m on the pump. I notice a marked increase in the potency of a brand new bottle of insulin. It seems to last about two set changes (I change every two days).

I kept my daughter’s Humalog out when she was first diagnosed. The doctor said in order for this to work you have to keep it in a place where there are no temperature fluctuations. It worked fine, but if I didn’t have the new vial at the end of 28 days I would notice her BG going up. Now I keep it refrigerated and it works fine for at least an extra week if I need it to.

New insulin vials are always more potent. Unopened vials should be refrigerated. Every time the seal is punctured, it degrades a bit. I keep mine refrigerated (used or new) or cool (used) in a Frio wallet. Even though opened insulin doesn’t technically need to be refigerated, I think keeping it at the same consistent temp helps.

Hello Mr. Johnben,

You are special! But…I’ve been doing the same thing, for the past three months. Always towards the end of the month, yes, my Bg’s have been going higher as well. I started a couple of days ago with keeping the vials in the fridge again. Thanks for your post, it confirmed what I had thought.


I use Apidra and I haven’t noticed any change from the day I open it to when it’s empty… I don’t cart mine around with me though, once a vial is open, unless I go out of town, it just sits next to the sink in the master bathroom. I use up a vial on average in 12-14 days, so it’s rare that I have a vial open for longer than that… I go through 2 1/2 to 3 bottles a month after what is wasted (and I no longer feel the need to suck out the last few drops in a vial either).

Now, I can say that I have notices significant changes in potency/action between different lot numbers… for example I had a bunch set to expire in September of this year that seemed to be a bit “slower” than I had been experiencing and I needed much more of it to bring down high #'s. Changing to a lot # that expires 12/2011 and things are back to what was ‘normal’ before I started using the 9/2011 batch. I tend to have 4-6 vials of any one lot number, so I can get a consistent stretch before I need to worry about differences… typically a new lot # will mean minor changes in basal rates and I:C… so it’s nice to be prepared to make those changes rather than wondering what the heck is going on with my #'s.

This is confusing to me. Not long ago it it was stated here that keeping it in the fridge would just not work as well as when it was kept out. It was said that unopened bottles only should be kept in the fridge. So after 50 years of keeping and using the insulin in the fridge even after opening I tried to keep it out after opening.

Yes, 50 years ago we had fridges already…LOL. Confusing, confusing… Thanks for all the replies. Back into the fridge again.

Just from a different perspective, I use Apidra and the OmniPod insulin pump. I have been told to use room temp insulin when filling the pods, so yes I keep my opened insulin vial at room temp. But even before using the pump, I kept the opened vial at room temp.

I am a pump user. I have been instructed to leave the insulin at room temperature. The reason is that if the insulin is cold when a cartridge is filled, the insulin will “shrink” and cause air bubbles in the cartridge, which is not good. I only use about 20 units of insulin per day, so a bottle lasts me a while. I have never noticed any differnce in the action of the insulin.

By the way, when I used Lente some 40 years ago, I was also told not to refrigerate the bottle I was usingt. I was told it mixed better at room temp.

I too am a pumper and I keep my insulin refrigerated all of the time. When I need to do a site change, then I take insulin out of fridge for 1/2 hour to bring it up to room temp. Draw out the required amount and then pop it back in the fridge. It always lasts me 30 days.

Thanks to All


I keep my opened bottles of Lantus and Humalog at room temperature and carry them with me all the time. I also use them until they’re gone, which is about 45-50 days. I don’t have insurance so I try to stretch as much as I can. I do check my blood sugar more towards the end of the vial though to make sure it is still working correctly. Haven’t had any problems so far.

Jon, I have not noticed an issue with insulin being kept unrefrigerated but my insulin only lasts about 2 weeks. I have noticed that at the end of 3 days sometimes the insulin in my pump seems to be less effective. I have not confirmed this but it seems to be a frequent pattern. I wonder if keeping it in my pocket against my warm body is worse than using a belt clip??

In previous discussions on TuD, it was suggested that the plastic in the reservoir degrades the insulin by three days. My experience says that that suggestion is probably true, at least for me. After 2 1/2 days, the pump insulin quits. I keep my Apidra in the fridge all the time except just before I fill a reservoir for the pump, when I leave it out to warm up 20-30 minutes. If I travel with insulin, in my car–whatever–I put it in an insulated container with ice.

Thanks to all of you!


One interesting thing I learned recently about this was about refridgerated insulin in pumps. When I called into Animas, I was told that I was SUPPOSED to use room temperature insulin to fill my cartridges, otherwise oxygen would be released as the temperature changed. Nobody had ever told us that. Another thing: When I was in the emergency room for a broken leg and had to borrow some insulin, I found out that once hospitals open their insulin, they don’t refridgerate it. They open it, keep it out, and throw it away after a month. They do, however, refridgerate it before they open it. I hope this information helps!