Propylene glycol, a super common ingredient in skincare and cosmetics, can cause two types of skin problems: irritant reactions (like redness or burning) and allergic sensitization (where your skin develops an allergy to it over time). The study reviewed existing research to understand how often and why these reactions happen, and found enough evidence that people with sensitive skin should be aware of this ingredient.

The researchers reviewed published scientific literature on propylene glycol to summarize what's known about its ability to trigger skin irritation and allergies.

Funding not disclosed in abstract