Insulin Bottles differing?

Each week I try to pick one thing to work on with my diabetes. It may be as simple as learning to use my small purse size scale for restaurants or as big as conquering the super bolus regime to knock down spikes.

My question for this week has been a nagging one…I find sometimes that I will have great control, things are working great with the pump settings as they are. The variables I can control are controlled…ie…I weigh everything and dose for each bite that goes in my mouth. Then it’s time for a new bottle of insulin…and wham…everything goes somewhere in a hand basket… It has to be the insulin. Last night I was on the 2nd draw off a new bottle and the previous 5 days on this new insulin have been off. Not enough to make me sick but instead of waking up at 100 I wake up at 130. Spikes are higher…harder to bring down. I eliminated all the questionable variables…used a good site for the 2nd draw…pump is working find. Foods are weighed and calculated correctly…Not fighting an infection…etc…etc…

I opened a new bottle of insulin last night and using the same site, just filling a new cartridge and tubing and bam…within in 20 minutes I could feel the difference. I was 87 around 2 am and woke up at 102 this morning.

Is there really that much difference between bottles or lots of insulin? (I use Humalog) I thought this stuff was supposed to be identical from bottle to bottle? Has anyone had a similiar experience? Got any theories?

Thanks for the answers in advance! I’ve learned so much this last month from this site and hope to keep on learning. Until the day there is a cure and then I am going to learn how to knit…


Activity is not perfectly identical bottle-to-bottle and you are probably noticing something in the few percent area of differing activity. Even if it’s manufactured in the same plant in the same batch, storage time and storage temperature come in at the few percent level.

Do a little research in the pharmaceutical textbooks on the defnition of a “unit of insulin” and you’ll be surprised:

Insulin is measured in units, abbreviated U
(international units, previously abbreviated IU).
One unit of insulin is defined as the amount of
insulin that will lower the blood glucose of a
healthy 2 kg (4.4 lb) rabbit that has fasted for
24 hours to 2.5 mmol/l (45 mg/dl) within 5

I tend to agree with you John, if it were me and my bg’s, I would never chalk up something as small as a bg discrepancy of 30 mg/dl to the bottle of insulin. But others here have different goals and standards.

I’ve never noticed differences in a bottle of insulin. I do notice differences in sites due to absorption. For us a 30 pt variance in waking is not a huge deal, but my DD is a teen.

I do see a difference in insulin resistance at different times of the month – maybe this is part of it for you? Some days are much more forgiving than others. I have all the charts from the cgms so I can see it is a monthly pattern. I also see insulin resistance when she eats a lot of fat.

I understand those are small discrepancies…but I feel them. I feel crummy in the morning with those higher numbers and it just gets worse at the day goes on and food is added into the mix. It can sometimes ruin a perfectly good day. So if I can identify the problem I’d like to. I’m going to try keeping the same lot of insulin for a month. If I just have to adjust between lots that is easier. I go through a bottle of insulin in 10 days so adjusting every 10 days is complicated especially when it will take about 3 days to clear out any other variables that could be causing the problem.

I’m also going to try doing a workout when i suspect bad insulin…I can drop like a rock with good insulin and actually go higher with bad. That being that the site is good and the pump is functioning well and any other variable is controlled as best I can.

Another “symptom” I have with not getting enough insulin is the munchies! If I go too long without insulin I get the dreaded nausea.

Yep…things change frequently!



I absolutely notice some change between lots… so much so that I’ve actually arranged all of my insulin in the fridge by lot # so that I can continue using the same lot without switching back and forth. The differences I notice ARE relatively minor though… but usually I end up needing to tweak my basals by about 5% one way or the other, but my ratios stay the same - it’s been my experience that when my basals are “off” the carb ratios just don’t work - I’m either getting too much insulin (when basal rates are on the high side), causing lows, or not enough (basals too low), causing highs, and much harder to control BG’s overall.

I use up a bottle in about 10 days just like you do, so if I was constantly tweaking my basal needs in 10 day cycles I would go insane - it’s hard enough just to stay on top of changing female hormone levels :slight_smile: Usually I have at least 4 bottles from a lot since that is what I get at a time from the pharmacy… sometimes I have longer runs, but sticking to the same lot #'s definitely makes things a little simpler - plus I know when I change to a different lot # I should expect some variance.

Personally I have a theory that the differences may not be tied to specific lots as much as the storage conditions those bottles went through getting to me… I have no idea how it was stored or treated before I picked it up.

I’m gonna do that…I checked this bunch of insulin that I just picked up and 3 of the 4 bottles are from the same lot. I’ll use those first and see how my days go.

Yesterday was wicked…I’m tired of fighting blood sugars…I’m tired of being a detective…

I want a new job…being a pancreas is no fun and the pay stinks…


I’ve had the same thing happen, not just in me, but in those I’ve been caregiver for. I put mine by lot #. Important to me.