[lilituc]

I've had Novolog go bad. Like other insulins, it's not the suddenly going bad you need to worry about, because you can tell that if you look at the vial. When it goes bad normally, it just loses effectiveness. This happened to mine once when I was travelling in a car and it was sitting in a bag under the heater. The bag didn't feel that hot or anything, but after two hours, it suddenly was only about 50% effective. I know because I had to use it until I could get a new one. I'm still not sure why this happened when it wasn't that hot, though.