The harmful chemicals in vape juices SEATCA Most vapes contain dangerous chemicals that can harm your lungs, heart and brain, but did you know that the very act of vaping and sucking in air could in itself lead to PG Propylene Glycol vs VG Vegetable Glycerin All you need to know Toxicity of humectants propylene glycol and vegetable glycerin in electronic nicotine delivery systems ScienceDirect The combination of propylene glycol and vegetable glycerin e cigarette aerosols induces airway inflammation and mucus hyperconcentration Scientific Reports