Insulin potency: Pump vs Vial

Hi gang!
I’ve been pondering this question for a while… why is the insulin in a pump only good for three days (2 in my case) but the insulin vial unrefridgerated is good for 28 days? I never questioned it before because I figured with an omnipod the insulin might be warmer because it’s closer to the body - but other pumps can be worn away from the body, so the reservoir would be at room temperature like an insulin vial. Plus “room temperature” varies across the country/world. Any idea why this is? Thanks!

I think it varies because different counrtries have different temps. And because not all countries messure in Ferinheit.

Thanks @AAT1D!
I should clarify - I am inquiring as to why insulin is only good in pumps for 3 days but ok in insulin vials for 28 days at room temperature.

It’s because of the glass vs. plastic.

It’s because in a pump the temperature climbs to 99 F and you are shaking it

@ami-one the way the insulin manufacturers do this is by testing insulin efficacy and microbe (genetic typicalled viables) growth over time. For refrigerated insulin (not frozen) the vial is good until expiry. Once you use it you’ve exposed it to potential contamination typically from drawing air into your syringe and filling the vial) so they say “30 days”

The manufacturer test for confidence, meaning if they say 30 days then usually 99.9999 or better percent of vials tested are still good. Can you go longer? - of course.

The only difference in a pump is higher temperature because it’s on your body and under your covers and shaking. Both (agitation and temperature) are really bad for protein degradation.

Hope it helps

Thank you @joe!!! This makes sense. I’ve heard from people who pay out of pocket for their insulin that they reuse the leftover from one set to another. Figured it wasn’t ideal. Tricky enough to match bg and insulin under ideal settings. Feel free to add more if you learn of any other factors.