Although they do not produce tobacco smoke, e-cigarettes still contain nicotine and other potentially harmful chemicals. While several studies have found that e-cigarettes produce lower levels of carcinogens when compared to smoke emitted by traditional cigarettes, very little is really known about the health risks of using them. Due to the lack of scientific evidence on the health effects of using e-cigarettes, for now, they cannot be recommended as a safe and helpful way to quit smoking.