Propylene glycol
PG · E1520 · "humectant" · "solvent"
A synthetic, colorless, slightly sweet liquid used to keep moisture in baked goods, dissolve flavors and colors, and prevent ice crystals from forming in frozen desserts. Yes, a related compound shows up in antifreeze — but the truth is more nuanced than the viral headlines suggest.
Why we flag it
The "propylene glycol is in antifreeze" claim needs unpacking. The toxic antifreeze most people picture is ethylene glycol — a different molecule. Propylene glycol is actually the safer alternative used in pet-safe and food-grade antifreeze formulations. The FDA classifies food-grade PG as Generally Recognized as Safe at typical intake levels.
That said, "safer than ethylene glycol" isn't the same as "ideal." PG can cause skin irritation and allergic reactions in sensitive people, and high doses have been linked to lactic acidosis in people with impaired kidney function. The European Food Safety Authority sets a much lower acceptable daily intake than the FDA, and the EU prohibits its use in many product categories. We flag it as a marker of heavy industrial processing — it's rarely in food you'd otherwise call "clean."
Where you'll find it
Anywhere texture, moisture, or flavor stability matters in processed food:
- Salad dressings, marinades, and sauces
- Cake mixes, frostings, and snack cakes
- Ice cream, soft-serve, and frozen desserts (prevents iciness)
- Drink mixes, flavored coffees, and energy drinks
- Flavoring extracts and food coloring carriers
- Soft and shelf-stable packaged baked goods
- Some processed cheeses and shredded cheese (anti-caking)
- Liquid medications, e-cigarette vapor liquids, and cosmetics
What to look for instead
Real ingredients deliver the same texture and flavor without the synthetic solvent:
- Glycerin (vegetable glycerin) — a closer-to-nature humectant from plants
- Honey, maple syrup, or molasses — natural humectants that keep baked goods moist
- Real cream and butter in ice cream — fat handles texture without solvents
- Fresh vinaigrettes and homemade dressings — emulsify with mustard or honey instead
- Whole, fresh ingredients — propylene glycol mostly disappears from your diet when you cook more from scratch
USDA Organic certification prohibits propylene glycol in food.