Potentially toxic ‘forever chemicals’ found in smartwatch wristbands – as scientists recommend which ones to buy

ELEVATED levels of potentially toxic “forever chemicals” have been found in several smartwatch wristbands.

The chemicals may be more common at certain price points, say scientists.

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PFAS (Per- and polyfluorinated alkyl substances), also known as forever chemicals, are a large family of more than 10,000 long lasting chemicals, whose components break down very slowly over time.

Smartwatches and fitness trackers have become popular forms of wearable tech, strapped to many people’s wrists day and night.

But new research by American scientists warns that they may expose the skin to forever chemicals in the process.

More expensive wristbands made from fluorinated synthetic rubber revealed “particularly high” amounts of one forever chemical, perfluorohexanoic acid (PFHxA), according to the study published in the journal Environmental Science & Technology Letters.

Author Professor Graham Peaslee, of the University of Notre Dame, Indiana, said: “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.”

Because PFAS repel water, sweat and oil, manufacturers include the chemicals in many consumer products, such as stain-resistant bedding, menstrual products and fitness wear – including smartwatch and fitness tracker wristbands.

The bands contain fluoroelastomers – synthetic rubbers made from chains of PFAS – to prevent discolouration and repel dirt.

Though the durability makes the bands great for sweaty workouts, the researchers say it might also make it easier for these compounds to get under the wearer’s skin – literally.

Prof Peaslee plus co-authors Alyssa Wicks and Heather Whitehead examined several commercially available watchbands for the presence of fluorine, as well as 20 individual PFAS.

They screened 22 wristbands from a range of brands and price points, most of them newly purchased but a few previously worn.

All of the 13 bands advertised as being made from fluoroelastomers contained the element fluorine.

But two of the nine bands that did not advertise being made from fluoroelastomers also contained fluorine, indicating the potential presence of PFAS.

Of those tested, wristbands that cost more than $30 contained more fluorine than those under $15.

Next, following a chemical extraction, all the wristbands were checked for 20 different PFAS.

PFHxA was found to be the most common, appearing in nine of 22 tested wristbands.

The median PFHxA concentration was found to be nearly 800 parts per billion (ppb), and one sample exceeded 16,000 ppb.

Comparatively, previous research by the team in 2023 on cosmetics found a median concentration of around 200 ppb of PFAS.

Prof Peaslee said: “We have never seen extractable concentrations in the part-per-million range for any wearable consumer product applied to the skin.”

The team suggest that the large amounts of PFHxA found in the wristbands may be a result of the compound being used during the fluoroelastomer manufacturing process.

Scientists don’t currently understand how much PFHxA transfers into the skin, nor how it could affect health once it gets there.

But Prof Peaslee says recent studies suggest that a significant percentage of the chemicals could pass through human skin under normal conditions.

Study lead author Ms Wicks says the team recommends buying lower-cost wristbands made from silicone.

She added: “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.”

PFAs were detected in fruit and veg sold in the UK earlier this year.