I have been taking Lantus for years because my blood sugars tend to shoot up while I am sleeping overnight. If I go to bed with my sugars high, Lantus will keep it there. Similarly, if I got to bed with a normal blood sugar reading, the insulin will keep it there. Lantus is less about moving your blood-sugar number than it is about keeping it wherever you get to with short-acting insulin. Were I to use long-acting insulin alone, I would never get a number between 85 and 115, normal for me. An endo once explained it this way to me .... think of short-acting insulin as runner in a footrace. Short-acting is the cheerleader that helps you keep going at whatever "pace" you set.