What Are the Ingredients in Vape Liquids? Vaped Vaping 101: What is E Juice and How is it Made? I was stood in the kitchen, minding my own business and noticed my partners vape juice on the side. I found myself with nothing better to do than to read the ingredients 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. Understanding E Liquid Ingredients and Variations eJuiceDB