I have been taking Lantus for overnight and day coverage for about five years. I take 30 units twice a day, about twelve hours apart. It made a huge difference in my blood sugar and helped with spikes. Some diabetics won't need to take this even if they are taking an insulin like NovoLog with meals or on a sliding scale. I use the vial and syringe method but it is also available in pen format. This is something that is better for those with vision problems or for those who do not like to measure out their doses. Most doctors will prescribe this for patients who have spikes with their blood sugar levels through the day or wake up in the morning with high numbers. If that is the case you might only have to take 20 to 25 units before you go to bed. There are times when I forget to take this every twelve hours but as long as I remember to take it ever 16 hours I don't see huge spikes, if the gap stretches out longer than that then I see my numbers creep into the 200 range where my normal is 120 or lower. One of the biggest things to remember when taking this is that you have to give your body time to adjust to it. If your numbers aren't going lower when you test your blood sugar, don't give up on it because you are going to end up with the nasty side effects of diabetes like numbness and event neuropathy in your toes and feet, kidney issues and vision problems.