E Cigarette Use Among Youth Smoking and Tobacco Use CDC E Cigarettes and Vaping OHSU Time to kick nicotine habit once and for all Synergy Dental Clinic Researchers Find Toxic Metals in E Cigarette's Johns Hopkins Bloomberg School of Public Health Have you been thinking about trying vapes or e cigarettes? Think again! Most e cigarettes contain nicotine and other harmful substances. Some products claiming to be nicotine free have been found to contain nicotine. Nicotine Vaping Could Be 'Potentially Even More' Harmful to Hearts Than Smoking, Scientists Warn Newsweek