I also carry mine most of the time. I am careful to not leave it out in the sun as I live in Florida and the stuff is too expensive as it is. (uninsured here so I buy it every month out of my unemployed pockets.) I use Lantus, Novolog and Novolin R and I carry the Novolog/Novolin every where I go as I use it with meals and for adjustments.
So far I have never had an issue with it going bad and I sometimes use it past the 30 day mark due to cost.
I am not on pens anymore (pumping), but when I was, I would regrigerate only the unopened pens. Once I opened a pen, I would leave it room temp for the month. I do the same with my insulin vials now.
We don’t use the syringes anymore but when I did, we always kept the insulin in the frig. I actually thought that part of the reason to keep it refrigerated had to do with introducing germs into the vial every time you extracted more insulin and keeping it refrigerated kept them at bay. Now that we pump, I keep the vial my son uses on the counter because he goes through 1 vial in a week!!! (If I keep it refrigerated and try to fill his reservoir, I get too many air bubbles. ) I don’t know but that is what I read somewhere. When we had the pens, we were told to keep the extra cartridges in the frig but not to refrigerate the pens - something about the cold not being good for the mechanism in the pen. That is what we were told, but it appears many people are told different things!!!
As a followup, I found some unopened vials of humalog with an expiration date of 8/2007 which were picked up at 7/2005. They had been stored at 4c the whole time unopened.At lunch today I decided to test the five years hypothesis - I calculated lunch carbs, injected the proper # of units with a syringe, and tested every hour thereafter. The insulin worked fine - I went a tad low but that was probably due to syringe inaccuracy. I did not see any sediment or coloration in the vial. Ymmv of course depending on the insulin and temperature stability of your storage area, but I was impressed that it worked at all after almost four years.
To add the one thing is to not shake your insulin either especially Lente if anyone uses that anymore.
It is DNA and they are strands and can be damaged by vigorous shaking which can effect it’s performance.
I always keep the vials in the butter compartment of the fridge, and did so even before I got my first pump 15+ years ago. I always make sure that the vial and/or cartridge (aka syringe) is hand warmed before I put it in the pump. The real problem with bubbles in the insulin is that they will stay suspected for longer in colder liquids. So if I load 140 units in my pump then let it warm up in there until it’s used up several days later it’s inevitable that some bubbles will have separated out, and they may well end up being fed into the infusion set hose and go unnoticed, causing real problems.
The reason there is a supposed restriction of 27 days in use is that way back when, 1950’s or earlier, insulin was stored at a constant 86 degree F (or 30 C) temperature and it’s strength was tested at set intervals. They found it lost 1% of its effective strength at the end of 27 days, and set that as the standard. It DOES not fail totally or get dangerous. So if you’re really stuck sometime and the only insulin you have is past the 27 day at 86 F mark you can still use it, but you might have to take a slight bit more. Just be sure to test afterward, the difference of 1% of
30 units is only .3 units, which is a bit hard to measure in a syringe, but could be practical in a pump.
Keep the pen you are using at ROOM temp 24-7, all others just keep refrigerated. Are you in a HOT climate that the chemical bonds are going to be broken down by normal room temp usage??? Why would they ever go bad?
Stuart