Do e cigarettes kill you? Researchers don't know. Vox Going completely smoke free is difficult for many, but did you know that nicotine has been found in e cigarette liquids claiming to be 'nicotine free?' While e cigarettes don't contain tobacco, they may still Electronic Nicotine Delivery Systems and Cardiovascular Cardiometabolic Health Circulation Research Frontiers Prediction and potential risk factors for electronic cigarette use behaviors among adolescents: a pilot study in Chiayi, Taiwan