Zero-nicotine e-cigarettes are sometimes seen as safer because they do not contain nicotine. This study examined whether their aerosol could still affect the blood-brain barrier, which helps protect the brain from substances circulating in the blood.
Researchers used laboratory cell models and mice. Longer exposure produced changes in proteins that help maintain the blood-brain barrier and increased several inflammatory markers. These findings show possible biological effects, but they come from experimental models and do not prove the same effects occur in people.