If you've ever checked the ingredients on your moisturizer, salad dressing, or flavored coffee syrup, you've probably seen propylene glycol listed. It's an ingredient used as a humectant in skincare, a preservative and stabilizer in food, and a carrier for flavors and colors.

The FDA classifies it as "generally recognized as safe," and most people tolerate it without any problems. But for those with sensitive skin or certain allergies propylene glycol can cause unwanted reactions.

Here's what the research shows about potential side effects.

Skin Irritation and Contact Dermatitis

This is the most common issue with propylene glycol, especially in skincare products. Research has found that even low concentrations can trigger irritation in susceptible individuals, with reactions including redness, itching, rashes, and swelling.

In one study, undiluted propylene glycol caused noticeable redness and swelling in roughly 40% of participants during patch testing. People with pre-existing skin conditions like eczema or those with sensitive skin are at higher risk.

If you notice persistent irritation from a product, checking whether it contains propylene glycol could be worthwhile.

Could Cause Issues at High Doses

For the vast majority of people consuming propylene glycol in normal food amounts, there's no concern the body breaks it down within 48 hours. However, at very high doses (typically from medications or intravenous solutions, not from food), propylene glycol has been associated with serious effects including rapid heart rate, seizures in infants, and metabolic imbalances.

Certain groups should be more cautious: infants, pregnant women, and people with kidney or liver disease may have difficulty processing larger amounts.

So, Should You Avoid It?

For most people, propylene glycol in food and skincare products poses no risk. But if you have sensitive skin, eczema, or notice a pattern of reactions to certain products, it's worth investigating whether propylene glycol might be a trigger.

Apps like pom can help you quickly identify products containing propylene glycol, so you can make informed choices based on your individual sensitivities. You can flag it as a custom concern or use built-in filters for skin irritants and allergens.

Sources:

• Environmental Working Group. Propylene Glycol: Skin Deep® Cosmetics Database.

• American Academy of Dermatology. Contact Dermatitis and Propylene Glycol Sensitivity.

• U.S. Food and Drug Administration. Generally Recognized as Safe (GRAS) Food Ingredients.