I just started this week using e cig's. The first one I started with was "Cig20". 18mg. I got hits off of it like a real cigarette. But I overdosed.. and headed straight to get a lower dose, unfortunately they only have 0mg.as the next level down. I assumed that would be like smoking air. Furthermore the ones i just bought with another company,are 10-14mg known as a low dose nicotine. I have done all this in one week and spent about $100 just trying to get it right. I have learned though to just stick with what I have now. And in another week or 2 check out the 0mg. Also smoking real cigarettes with e cigs, is completing dangerous. If you think you have overdosed call your doctor immediately. It does take along time for the nicotine to go out of your system.