| In my case, taking Lantus in the morning, means I must wait four hours for the Lantus to be at 100%. So, sometimes I must bolus an extra unit or two during the Lantus "launch".
I just recently started doing morning fasts (still taking Lantus) to see how the basal rate was going. My first test showed I needed more basal units. Today I was even at 105...116...125...then back to 90 for about two hours before lunch. I also take a small split dose of Lantus at night that is factored into that morning fast.
I had just increased my a.m. Lantus by 3 units per endo's suggestion, (well she suggested more, but I do increases gradually to avoid the ER!) I may try a bit more in a few days and see if I'm still running good basals, or not...don't want to be too low.
But, if taking Lantus in mornings, many people forget about the 4-hour warm-up. See the package graph for a clear example, if needed. | 
