Propylene Glycol USP / Food Grade Common Use: Heat Transfer Fluids, Fragrance, Cosmetics and Personal Care, Food and Flavorings, Pet Food/Animal Feed. What is Propylene Glycol Propylene glycol is a clear, colorless, slightly syrupy liquid at room temperature. It may exist in air in the vapor form, although propylene glycol must be heated or briskly shaken to produce a vapor. Propylene glycol is practically odorless and tasteless. Propylene glycol is a chemical made by reaction of propylene oxide with water. Propylene glycol has had an unsurpassed reputation for safe use in a wide range of consumer products, including food products, animal feed, cosmetics and pharmaceuticals, as well as industrial applications. It’s used as a stabilizer (to keep things held together, and keep them from evaporating), and to keep foods moist. It’s used in many of the foods that we eat, and the FDA deems it safe for human consumption.