Hi! I use a pump and had to switch to Apidra from Humalog because my insurance doesn’t cover Humalog anymore. I don’t think that the timing is any different for me than the Humalog, but I definitely don’t think it works as well as the Humalog did. In fact, I’m planning to switch to Novolog when I run out of Apidra. I’d bet that stopper material will dull your needles. It seems like a very dense rubber, where as the Humalog wasn’t and was easy to pop a needle through. I wish I could be more helpful. I’m not sure whether keeping it cold will make a difference, though I do notice that after a couple days, my sugars swing more with Apidra, so maybe that will make the difference! Of course, trying to keep your insulin cold all the time is a pain in the butt. Could you switch back to Humalog or Novolog?