PFAS, or per- and polyfluoroalkyl substances, are pervasive chemicals found in a wide range of products we use daily, from cosmetics and food packaging to waterproof clothing. Recent research highlights a new concern: these chemicals can potentially pass through our skin, adding another layer to how we might be exposed to them.

A study led by environmental chemists from the University of Birmingham, published in *Environment International*, investigated how PFAS interact with human skin. Their findings show that certain PFAS can indeed penetrate the skin barrier and possibly enter the bloodstream. These chemicals, known for their “forever” nickname due to their extremely stable carbon-fluorine bonds, have been in use since the 1940s in items like nonstick cookware and water-repellent fabrics. Despite their benefits, they are now recognized for their harmful effects on health and their persistence in the environment.

In the U.S., PFAS exposure primarily comes from food packaging, indoor dust, and contaminated drinking water. The EPA has set new guidelines to limit PFAS levels in drinking water due to their concerning prevalence. While previous studies hinted at skin absorption as a potential route of exposure, data has been limited.

In this new study, researchers examined 17 types of PFAS, using lab-grown human skin models to simulate exposure. They applied a dose of each PFAS chemical to the skin models and monitored how much of the chemical passed through the skin barrier, remained in the skin’s surface, or was not absorbed.

Out of the 17 PFAS tested, 11 were found to cross the skin barrier, with those containing four to seven carbon atoms being more readily absorbed than longer-chain PFAS. For example, about 59% of perfluoropentanoic acid (PFPeA) and 49% of perfluorobutane sulfonate (PFBS) were absorbed into the skin and possibly into a simulated blood fluid. Though these shorter-chain PFAS were developed as safer alternatives, they are proving to be problematic as well.

Despite these findings, it is not yet confirmed that PFAS absorbed through the skin will definitely reach the bloodstream, according to Oddný Ragnarsdóttir, who now works at the University of Iceland. However, since PFAS can penetrate the skin, this is a concerning first step toward potential systemic exposure.

The study’s doses were higher than typical real-world exposure, which Miriam Diamond from the University of Toronto notes may not fully reflect everyday scenarios. Additionally, skin thickness varies across different body areas, affecting absorption rates.

Nevertheless, Ragnarsdóttir advises that consumers should be cautious about PFAS in clothing and personal care products. Extended contact with these products could increase exposure, making awareness of their presence in everyday items crucial.