E juice or e liquid is comprised of five ingredients - water, flavoring, propylene glycol, vegetable glycerin and nicotine (excluding zero nicotine liquids). Food-grade flavorings are used for many food-based applications, are safe to consume, and when combined correctly, can produce a wide variety of amazing vape juice flavors. Propylene Glycol is a colorless and odorless liquid that is used in many food and medical applications. This ingredient helps to evenly distribute taste and flavor throughout the vape e liquid. Vegetable Glycol is a natural chemical that is derived from vegetable oil. It is used to give a thickness to the vapor and to smoothen out the harshness of PG.