Propylene glycol is in a surprisingly wide range of everyday products, from salad dressing and ice cream to moisturizers, medications, and airplane deicing fluid. It’s a synthetic, colorless, nearly tasteless liquid that absorbs water easily, which makes it useful as a moisture-retainer, solvent, and preservative across dozens of industries. The FDA classifies it as Generally Recognized as Safe (GRAS) for use in food.
Foods That Contain Propylene Glycol
The list of food categories where propylene glycol is approved as an additive is long. It serves multiple roles depending on the product: keeping things moist, dissolving flavor compounds, preventing clumping, and stabilizing textures. You’ll find it in ice cream, sherbet, pudding, and other dairy-based desserts. It’s in soft drinks (both carbonated and non-carbonated), flavored drink concentrates, and even some alcoholic beverages.
Baked goods are another major category. Bread, cakes, cookies, doughnuts, muffins, scones, and pancake mixes can all contain it. So can dried fruit, candied fruit, fruit fillings for pastries, and fruit toppings. It shows up in processed vegetables and nuts, dried pastas and noodles, batters for breading fish or poultry, and snack foods made from potato, cereal, or flour.
Condiments and seasonings rely on it too. Propylene glycol is used in mustard, ketchup, mayonnaise, salad dressings, cheese sauces, gravies, ready-to-eat soups, herbs, spices, and seasoning packets. It’s also present in confectionery and even in table salt as an anticaking agent. In many of these products, its primary job is acting as a carrier solvent for food colorings and flavorings, dissolving them evenly throughout the product.
Skin Care and Personal Care Products
Propylene glycol is one of the most common ingredients in cosmetics and personal care products. It appears in moisturizers, serums, shampoos, conditioners, deodorants, and makeup. It performs three useful functions in these products. As a humectant, it pulls water into the skin and helps hold it there, which is why it’s a staple in hydrating formulations. As a preservative, its mild antimicrobial properties help extend shelf life. And as a penetration enhancer, it helps active ingredients absorb more effectively through the skin.
Most people tolerate it without issue, but it can cause irritation or contact dermatitis in some individuals, even at concentrations as low as 2 percent. Contact allergy to propylene glycol is relatively uncommon, estimated at up to 3.5% of people who are tested for suspected contact dermatitis. If you notice redness or irritation from a product and can’t pinpoint the cause, it’s worth checking the ingredient list for propylene glycol.
Medications and Pharmaceuticals
Propylene glycol is a widely used pharmaceutical excipient, meaning it’s not the active drug but helps deliver it. It acts as a solvent to keep ingredients dissolved and stable. It’s found in oral solutions, injectable medications, topical creams and ointments, and inhaler aerosols. Concentrations vary by product type, ranging from about 5% in some topical formulations up to 60% in certain injectable solutions.
Common medications that use propylene glycol as a solvent include certain anti-anxiety drugs, sedatives, antibiotics, pain relievers, and antiviral medications. It’s also in some multivitamin solutions used in hospital settings and in topical burn treatments. For most patients taking standard doses, the amount of propylene glycol in a medication is too small to cause any problems. Toxicity concerns arise mainly in hospital settings where patients receive large, continuous intravenous infusions over extended periods.
E-Cigarettes and Vaping Liquids
Propylene glycol is one of the two base liquids in virtually all e-cigarette liquids, alongside vegetable glycerin (VG). In vaping, propylene glycol carries the flavor and nicotine, dissolving them more effectively than vegetable glycerin does. It also produces the “throat hit” that mimics the sensation of smoking tobacco and creates a thinner, lighter vapor similar in density to cigarette smoke.
E-liquids come in various ratios of VG to PG, typically ranging from 50/50 to 90/10 (VG/PG). Higher propylene glycol ratios deliver stronger flavor and throat hit but produce less visible vapor. Some products are labeled “max PG” for users who prioritize flavor intensity, while “max VG” products minimize propylene glycol for smoother, cloudier vapor.
Industrial and Non-Food Uses
Outside the kitchen and medicine cabinet, propylene glycol has a significant industrial presence. It’s a key ingredient in antifreeze and deicing solutions for cars, airplanes, and boats. It’s specifically chosen for these applications in situations where leakage could lead to contact with food or animals, because it’s far less toxic than the alternative, ethylene glycol. It’s also used as a solvent in the paint and plastics industries, as a raw material for making polyester compounds, and as the base for artificial smoke and fog machines used in theatrical productions and firefighter training.
How Your Body Processes It
One reason propylene glycol has such broad approval for food and pharmaceutical use is that the body handles it efficiently. Your liver breaks it down into lactic acid and then pyruvic acid, both of which are normal components of your body’s energy-production cycle and are further converted into carbon dioxide and water. About 45% of an absorbed dose passes through the kidneys unchanged.
This metabolic pathway is what separates propylene glycol from its more dangerous chemical cousin, ethylene glycol, the compound historically used in conventional antifreeze. Ethylene glycol breaks down into oxalic acid, which is toxic to the kidneys and can be fatal. Propylene glycol’s breakdown products are harmless at normal exposure levels, which is why it replaced ethylene glycol in any application where human or animal contact is possible.
Why It’s in So Many Things
Propylene glycol’s versatility comes down to a handful of chemical properties that are hard to replicate with a single alternative. It absorbs and retains water, which keeps products moist. It dissolves a wide range of substances that don’t dissolve well in water alone, making it an effective carrier for flavors, colors, and active drug ingredients. It lowers the freezing point of water, which is useful for both deicing fluids and frozen desserts. And it has mild preservative qualities that help prevent microbial growth. Few other compounds check all of those boxes while also being low in toxicity, odorless, and nearly tasteless.