PG (Propylene Glycol) E Liquid Base Make My Vape Understanding Vape Juice: Ingredients, Varieties, and Safety General Vape Nicotine, propylene glycol, sweet flavorings, and various toxic chemicals like carcinogens and heavy metals are found in vape juice, posing health risks, especially to youth. Vape Juice Ingredients: What's Inside Your E Liquid? VITAE Glass VG vs PG Explained: E Liquid Ratios Guide Ecigone Do you know what you're vaping? Propylene glycol (PG) and vegetable glycerin (VG) are the main liquids in vapes. When heated, these chemicals turn toxic and aren't safe to breathe.