JUUL delivers substantially more nicotine to the blood per puff than cigarettes or previous-generation e-cigarettes (e-cigs) and impairs blood vessel function comparable to cigarette smoke, according to a new study by researchers at UC San Francisco.
The study, which appears online Jan. 4, 2019, in Tobacco Regulatory Science, found that nicotine concentrations were five to eight times higher in rodents that were exposed to JUUL versus other tobacco products. The work also supports an earlier finding by the same researchers of harm to blood vessels from brief exposures to both direct and secondhand smoke from cigarettes, little cigars and combustible marijuana, and to aerosol from IQOS “heat-not-burn” tobacco products.
JUUL and earlier generation e-cigs are promoted as being less hazardous than cigarettes. Since 2016, there has been a dramatic increase in youth e-cig use, with JUUL devices particularly effective at recruiting teenagers to begin nicotine usage. A recent study found 27.5 percent of high school students and 10.5 percent of eighth graders currently use e-cigs, with more than half of both groups using JUUL as their preferred choice.
A caveat of this study is that it measured the impact of equal numbers of puffs of all products, whereas adult former cigarette smokers may stop their vaping session when they reach the level of nicotine they normally ingest, said senior author Matthew Springer, PhD, professor of cardiology at UCSF and member of the UCSF Center for Tobacco Research and Education.
“However, adolescent non-smokers who are not familiar with the effects of nicotine may be more likely to chase higher levels of the drug’s effects,” Springer said. “The ease of over-consuming nicotine with JUUL makes this likely, especially in light of reports of teenagers binging on JUUL to the point of rapid addiction and behavioral consequences.”
As with earlier-generation e-cigs, the liquid in JUUL pods is composed of vegetable glycerin and propylene glycol, along with flavors and nicotine. But while the freebase nicotine used in earlier generations limits the amount comfortably inhaled, JUUL has introduced acidified nicotine salts, which are easier to inhale and deliver nicotine at substantially higher concentrations.