Use patterns, flavors, brands, and ingredients of nonnicotine e-cigarettes among adolescents, young adults, and adults in the United States.

IQuestion: To what extent are nonnicotine e-cigarettes used, and what flavors, brands, and ingredients are most common? Findings: This cross-sectional study of 6131 US residents aged 13 to 40 years found that 25.9% had ever used a nonnicotine e-cigarette, 16.7% had used one in the past 30 days, and 12.4% had used one in the past 7 days; 18.8% had ever co-used nonnicotine and nicotine e-cigarettes. The most-used flavors were sweet, dessert, or candy flavors; fruit flavors; and mint or menthol flavors; most common ingredients were tetrahydrocannabinol, cannabidiol, melatonin, caffeine, and essential oils. Meaning: These findings suggest that a significant proportion of US residents are using nonnicotine flavored e-cigarettes marketed with unsupported health claims, which warrants further research, regulation, and prevention