Smartwatches can help improve our health and fitness. But a new report says it's important to consider what kind of bands we put on them, as several popular brands were found to contain high levels of a class of chemicals linked to health issues.
There's little room for debate about the manufacturing benefits of chemicals known as per- and polyfluoroalkyl substances, or PFAS. Produced since the 1940s, these chemicals containing strong carbon-fluorine bonds have found their way into industries ranging from aerospace to packaging. They are quite good at resisting oil and water, so they have also been used in non-stick coatings, umbrellas, stain-resistant coatings on carpet and clothing, cleaning products, and personal care items like makeup and shampoo.
While efforts to find ways to eliminate them are under way, the durability that makes PFAS so desirable in manufacturing also means that they don't break down once they are created and released into the world, a trait that has earned them the designation of being "forever chemicals." Due to their ubiquitous nature in manufacturing, these chemicals are also starting to find their ways into our bodies, where they've been linked to a wide range of health concerns including cancer and diabetes.
Now, a new study has found disturbingly high levels of a particular type of PFAS known as perfluorohexanoic acid (PFHxA) in watch bands, most of which are used to strap smartwatches to our wrists.
"This discovery stands out because of the very high concentrations of one type of forever chemical found in items that are in prolonged contact with our skin," says study co-author Graham Peaslee from the University of Notre Dame in Indiana.
In the study, the researchers tested 22 different watch bands made by Apple, Google, FitBit, Samsung and others for 20 different PFAS. PFHxA was found in nine of the bands, representing the most commonly found PFAS in the study. More concerning than its presence, however, was its concentration. The median concentration of PFHxA was nearly 800 parts per billion (ppb) with one sample exceeding 16,000 ppb.
For comparison with something else that regularly touches our skin, the researchers previously found PFAS concentrations in cosmetics to be just 200 ppb.
"We have never seen extractable concentrations in the part-per-million range (>1000 ppb) for any wearable consumer product applied to the skin," says Peaslee.
Elsewhere, the European Commission has deemed PFAS to be such a problem that a restriction is set to go into effect in October 2026, which caps PFHxA limits in cosmetics at no greater than 25 ppb.
False-ish advertising
Thirteen of the watch bands tested by the researchers advertised that they were made from PFAS known as fluoroelastomers, a kind of synthetic rubber. As expected, all 13 of those bands were found to contain fluorine, a hallmark of PFAS usage. The other nine bands didn't mention the use of fluoroelastomers, yet two of them were also found to contain fluorine.
While the researchers didn't reveal the direct levels of PFAS on a brand-by-brand basis, they did say that bands that cost more than $30 had more fluorine than those under $15, meaning that they were likely higher in overall PFAS content.
While PFAS have been found inside the human body for years, scientists are still not quite sure how readily PFHxA in particular transfers through the skin or what the effects are once it is inside of us. Therefore, the researchers are not making any health claims regarding the potentially damaging effects of wearing watch bands containing the chemicals.
Still, study lead author Alyssa Wicks says consumers should take their findings into account if they are shopping for new watch bands.
"If the consumer wishes to purchase a higher-priced band, we suggest that they read the product descriptions and avoid any that are listed as containing fluoroelastomers," she concludes.
The study carried out by Wicks and her team has been published in the journal, Environmental Science & Technology Letters.
Source: American Chemical Society