UC San Diego

Waterpipe tobacco (WPT) smoking is a public health concern, particularly among youth and young adults. The global spread of WPTuse has surged because the introduction of pre-packaged flavored and sweetened WPT, which is widely marketed as a safer tobaccoalternative. Besides flavorants and sugars, WPT additives include humectants, which enhance the moisture and sweetness of WPT,act as solvents for flavors, and impart smoothness to the smoke, thus increasing appeal to users. In the United States, unlikecigarette tobacco flavoring (with the exception of menthol), there is no FDA product standard or policy in place prohibiting sales offlavored WPT. Research has shown that the numerous fruit, candy, and alcohol flavors added to WPT entice individuals toexperience those flavors, putting them at an increased risk of exposure to WPT smoke-related toxicants. Additionally, burningcharcoal briquettes—used as a heating source for WPT—contributes to the harmful health effects of WPT smoking. This reviewpresents existing evidence on the potential toxicity resulting from humectants, sugars, and flavorants in WPT, and from the charcoalused to heat WPT. The review discusses relevant studies of inhalation toxicity in animal models and of biomarkers of exposure inhumans. Current evidence suggests that more data are needed on toxicant emissions in WPT smoke to inform effective tobaccoregulation to mitigate the adverse impact of WPT use on human health.