Lantus potency

Hey all! We made it through our first Christmas with minimal tears and maximum blood sugars. :pensive:. My 12 year old son’s sugars were the highest they’ve been since dx (6 months ago). I know that this could be caused by holiday stuff, excitement, sickness, all of the usual suspects, but I am also noticing a pattern with his Lantus. It seems that when we get close to the end of 28 days with the bottle of Lantus it’s potency goes way down. In the past if he goes to bed with somewhat elevated blood sugar, when he wakes up the Lantus has taken the edge off. Now, it almost seems that if he doesn’t have the fast acting in him, he doesn’t have any insulin in him period. If this is a thing other people have dealt with, I’d love some solutions. Thanks so much and happy holidays!

Hello, and congratulations on Christmas!
How do you store his Lantus? Although they now say you can keep “in use” insulin at room temp, I keep mine in the fridge (as instructed when I was diagnosed as a very young child). If you keep it chilled there may be more air bubbles to get rid of though. Just a thought.

Hi, Lucy @lucyinthesky827.

I’m with Dorie @wadawabbit. I have always been suspicious of insulin products that have not continued to be refrigerated. The bottle of Humalog that I am using to fill my pump reservoirs always stays in the refrigerator and, most of the time, I can continue to use the bottle without loss of potency well past the “recommended” 28-days.

When I travel I do store my active bottle of Humalog in my travel kit so it does reach room temperature and stays there for the duration of the trip. But I work hard to ensure that my travel kit does not get “heated up” by direct sunlight (or other heat sources).

I have returned home from trips with concern that my vial of insulin got too warm. In those situations I carefully monitor my glucose response when I refill my pump using the “suspected vial” and, if I see a pattern of all-day elevated blood glucose levels that I can’t attribute to anything else, I throw the “suspect vial” away and refill my pump from an unopened (and refrigerated) vial. That tends to solve the problem.

As you may know, when insulin products were first developed they were “extracts” from the pancreases of slaughtered cows and pigs. The “extracts” were as carefully filtered as could be done at the time. But. despite their best efforts, the insulin products that were available still included “other proteins,” and those were the source of all kinds of things that would “grow” in the vials of insulin if they were not kept “refrigerator cold.” Indeed, the “rule of thumb” was to look at the vial for evidence of “cloudiness” or “sediment” before you drew up insulin for an injection. If you saw “cloudiness” or “sediment,” you were to throw the bottle away and use a new vial of insulin. Keeping the insulin cold was a must.

If you/your son does keep “in use” vials of insulin at room temperature, I would encourage you to “move the butter aside” in the door of the refrigerator and keep it there. For me the above routine has eliminated many unwelcome “surprises,” and gives me confidence that the potency of my insulin preparation will remain predictable.

Glad your son made it through his “first” Christmas. I wish him, you, and the rest of your family the best of luck and endurance.


Lucy @lucyinthesky827, I used Lantus for a couple of years, from the month it was approved until I began using a pump, but that was long ago. I do not now recall loss of potency and at that Time I was traveling often for work and my insulin was subject to weather extremes.

As I recall, Lantus was the “long sot after” insulin that didn’t have peeks & valleys and was designed to keep BG level. That said, I would suggest [and discuss this with your son’s doctor], that instead of expecting the Lantus down from an “unusual high” that you add a bit of fast or rapid-acting insulin to his daily Lantus on those occasions. I’m suspicious that his established Lantus might be too much of it has the side-effect of causing his BG drop from something like 225 to 120 mg/dl overnight without the assist of fast-acting.

Change is the one thing that is constant while trying to manage diabetes; as his doctor must have told you, his insulin dose amounts will need adjustment from time-to-time.

Hi @BillHavins. I don’t think I ever knew the reason why we were told to keep our good old U40(!) pork or beef insulin in the fridge. Thanks for sharing the info. It was interesting - kind of gross, but interesting :blush:.