1,2 Propylene Glycol: A Biomarker of Exposure Specific to e Cigarette Consumption Researchers at the University of California, Riverside, found that heating propylene glycol, the main ingredient in most e cigarette liquids, can produce two toxic chemicals, methylglyoxal and acetaldehyde, which damage lung cells. Using Quelle utilisation du Propylne Glycol dans les Eliquide ? Tout comprendre sur le PG et le VG