Juul, the vape device teens are getting hooked on, explained Vox Let's talk vaping. Smokeless doesn't mean harmless. Most e cigarettes contain nicotine which is highly addictive and can harm adolescent brain development, which continues into the early mid 20's. Some e cigarettes can even JUUL Labs The Rise (and Stumble) of the E Cigarette Giant Juul will pay nearly $440 million to settle states' teen vaping probe : NPR Juul wanted to revolutionize vaping. It took a page from Big Tobacco's chemical formulas Tobacco 21