What you may have heard
Smart and fitness watch bands may contain cancer-causing “forever chemicals” known as PFAS (per- and polyfluoroalkyl substances). These are used in bands made of fluoroelastomer, a kind of synthetic rubber resistant to dirt, water, sweat, and oil. There is growing concern that PFAS in watch bands may be absorbed through the skin and increase your risk of cancer and other poor health outcomes over time.
What the science tells us
Elevated levels of PFAS may increase the risk of developing certain cancers, including kidney, testicular, and prostate cancer. PFAS exposure is also associated with negative reproductive effects, developmental delays in children, weakened immune function, hormonal disruption, and cholesterol regulation issues (EPA). Scientists are working to understand how forever chemical exposure from smart watch bands, specifically, may influence adverse health outcomes.
Epidemiological Evidence
The University of Notre Dame conducted a 2024 study on over 22 varieties of watch bands, finding high concentrations of fluorine, a key component of PFAS, in 15 of the bands. One compound in particular, PFHxA, was extracted from nine fluoroelastomer watch bands in high concentrations (Wicks et al.). These findings raise important questions about how regular skin contact with PFAS-containing bands might contribute to cumulative chemical exposure over time and call for further research.
Laboratory Evidence/Supporting Evidence
There is currently limited knowledge on PFAS absorption from repeated, prolonged contact with the skin. While laboratory studies have shown that forever chemicals can penetrate the skin and enter the bloodstream, the extent of absorption from everyday smart watch use is unclear.
How to reduce your risk
If you are concerned about potential PFAS exposure from smart or fitness watch bands:
- Check product labels. Avoid bands with the label “fluoroelastomer,” as they may contain PFAS.
- Choose watch bands made of silicone or untreated leather.
- Consider limiting the amount of time you wear your watch (e.g., take off during sleep).
- Wash your band and wrist regularly to reduce potential chemical buildup.
Bottom line
Several smart and fitness watch bands have been reported to contain PFAS. However, additional research is needed to determine how varying levels of PFAS exposure in watch bands may influence cancer risk. To decrease your potential risk from forever chemicals in smart watch bands, check product labels and look for bands without fluoroelastomers.