E liquid composition Vaping Post E Liquid 101: What's in Vape Juice? Flavour Beast 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. What's In Your Vape Juice? E Liquid Ingredients Explained EDGE Vaping What is Vape Juice? Ingredients, Flavoring & More ZampleBox Zamplebox What's in an e liquid or vape juice? The main ingredients are propylene glycol (PG) and vegetable glycerine (VG). These are solvents that are basically used to dissolve and carry the other ingredients.