Use of electronic cigarettes (e-cigarettes), vape pens, e-hookah, e-cigars, e-pipes, or other electronic nicotine delivery systems (ENDS) has increased rapidly since their introduction in the United States in 2007, growing to a $2 billion market.1 There is controversy concerning the utility of ENDS as a harm reduction strategy, reflecting major gaps in the emerging evidence on potential benefits and harms of the products.2-4 Although exclusive use of ENDS is generally considered to be less risky for individuals than smoking combustible tobacco products, there is concern that their availability may both lead to dual product use (ie, ENDS and cigarettes) and reduce cessation. Additionally, there is concern that ENDS may be used by nonsmoking adolescents and young adults who might not otherwise have used nicotine-delivering products, and that dual use may follow. Numerous flavored products that have seeming appeal to adolescents and young adults are on the market, such as Cherry Crush, Chocolate Treat, Snappin’ Apple, and Vanilla Dreams flavors; their availability may generate an entirely new population of nicotine-addicted users among never-users of combustible tobacco products.