BUT just this month (for a pump “vacation”) I’ve started using Lantus for the first time ever. Have any of you noticed that Lantus is more fragile than any other insulin? Do you actually throw out your nice, pricey, half-full Lantus vial after 30 days?

I never really had issues with the potency of the insulin I was using, in most cases where I thought their might be an issue I would find some other reason for the high (as the insulin was proved effective at a later date).

The only thing I would suggest not to do is let it sit in direct sun(so the rays are able to pass through the glass and degredade the insulin directly), but as far as potency in all my years with Type 1 I have never had an issue with insulin going bad and I have left open bottles in room temps (high and low) for most of these years without fail.

Dear Dr. Brange:
As a person living with Type 1 diabetes since 1967 I have seen a lot of changes in the types of insulins that are used to treat the disease and to control blood sugar.
I would be interested in any information that you have on the stability of Insulin at various storage temperatures. Most manufactures give basic information about insulin storage temperatures to preserve maximum activity. They generally say that the insulin is stable and active until the expiration date when stored at refrigerator temperatures and should be discarded after 30 days at room temperature. What is the “real story” on insulin storage and stability. I seem to be wasting a lot of insulin that I use because of the instructions to discard it after 30 days at room temperature. Lilly, Novo Nordisk, and Sanofi Aventis, are not much help. Where can I find the information that I am looking for. Thanks for your help; I look forward to hearing from you soon.

Dear Florian Menninger,
The real story is that the manufacturers of insulin have all reasons (FDA) to be on the safe side and not to promise too much. The true story is that even after 1 (one) year at 25 degrees the biological potency (blood sugar lowering capacity) of any insulin is still about 90-95% of its initial potency. During storage at room temperature degradation products of insulin are formed at a rate of a few percent per month, but the largest amount of these products have nearly full biological effect. The formation of such products is very much lowered in the fridge and insulin kept that way will retain its effectivity even after many years. I hope that it is what you needed to know in order not to discard too much insulin.
Best regards
Jens Brange, D.Sc.

The summer heat makes a huge difference, in my experience. I tend to wear more skirts in the summer that require me to wear the thigh holster for my pump. The insulin undoubtedly gets warmer than usual and thus has the tendency to go bad more often.

I suppose one workaround would be to fill the pump reservoir more often, using less insulin, so that the insulin doesn’t sit in the reservoir too long.

What a pain!

A test would be great though. As insulin users, we all know the importance of handling and storing insulin properly, but U.S. consumers also strongly encouraged by our healthcare providers to fill recurring prescriptions by mail instead of by local pharmacy. For me, it took a lot of courage and blind faith to accept insulin shipments by mail, but we really have no idea what environments the insulin is subjected to before finding the box left on our front doorstep.

This seems like a job for a more entrepreneurial (i.e. hungry) biotech company. Could you send the same query to that group? Maybe JDRF or NIH would offer a grant for R&D in this area.

what a fantastic idea! Some of the responses from the companies certainly reflect a lack of understanding on living with diabetes every day. Particularly for pumpers we can experience highs not just because the insulin is bad, but also because our catheter may be kinked. Before replacing infusion sets multiple times, it would be nice to know if the insulin itself is the culprit.

It was nice to see SANOFI-AVENTIS and to a lesser extent NOVO NORDISK at least acknowledge how useful it would be for diabetics to know if their insulin is still good without having to resort to trial and error…

Also, I had a vial I suspected was bad. I requested Lilly to check it out; they did and it was okay. I was still suspicious but later discovered the source of my problem, which was not the insulin.

-Anne