Your Smartwatch Could Carry a Hidden Health Risk

Newsweek

21-07-2025

Based on facts, either observed and verified firsthand by the reporter, or reported and verified from knowledgeable sources.
Newsweek AI is in beta. Translations may contain inaccuracies—please refer to the original content.
Smartwatch bands have been found to contain high levels of a potentially harmful chemical that researchers believe can be absorbed through the skin, raising the question of whether the popular accessory could pose a hidden public health risk.
A University of Notre Dame study published the American Chemical Society at the end of 2024, found the wearable tech contained significant amounts of "forever chemicals," per- and polyfluoroalkyl substances (PFAS)—specifically perfluorohexanoic acid (PFHxA).
The author of the study, Graham Peaslee, a professor of physics at the University of Notre Dame, Indiana, told Newsweek that "we found that it was almost entirely PFHxA leaching out of the wristbands."
"I believe the plastics industry has been using this particular PFAS in consumer products, which helps explain why it is so prevalent in the samples from this study," he added.
Peaslee also indicated that a significant proportion of these chemicals in wristbands could pass through human skin under normal conditions.
While traditional watch bands are made from a wide range of materials, from stainless steel to leather, smartwatch bands are typically made from more synthetic materials.
Smartwatch bands have been found to contain high levels of a potentially harmful chemical, raising the question of whether the popular accessory could pose a hidden public health risk.
Smartwatch bands have been found to contain high levels of a potentially harmful chemical, raising the question of whether the popular accessory could pose a hidden public health risk.
Photo-illustration by Newsweek/Getty/Canva
What Is PFHxA?
PFHxA, one of the thousands of compounds belonging to the PFAS family, is used widely in consumer products as well as for paper food packaging and carpets, but can be harmful to humans.
It has been found to have an impact on thyroid and liver function and, given it is part of the PFAS family, is by default associated with certain cancers as PFAS chemicals are classed a Group 1 carcinogen by the International Agency for Research on Cancer (IARC). There is, as yet, limited research directly connecting PFHxA to cancers.
Despite it's possible health impacts, it is not one of the PFAS molecules currently regulated by the EPA.
"Like most PFAS, the potential public health effects are still under investigation, but PFHxA is likely among the PFAS species that can accumulate in biological and environmental systems, including the human body," Christy Haynes, a professor of chemistry at the University of Minnesota, told Newsweek.
Compared with other PFAS chemicals, it is thought to have a smaller impact on the human body, because it is a shorter-chain chemical that was initially planned to be used as a replacement for perfluorooctanoic acid (PFOA), Jennifer Freeman, a professor of toxicology at Purdue University, Indiana, told Newsweek.
"Shorter chain PFAS usually have less concern for bioaccumulation in the body compared to their longer chain counterparts," she said.
Research is still ongoing, however, and studies have indicated PFHxA may cause similar adverse health effects to other PFAS chemicals, Freeman added.
PFHxA "has been largely unstudied because it only shows up in whole blood samples for humans" unlike other PFAS chemicals, which "show up in blood sera samples," Peaslee told Newsweek. This is because it "is much harder to measure whole blood," he said.
But, as a result of its "hazardous properties," the European Commission is looking to restrict the use of the chemical because of the risk to health it poses, requiring certain industries to scale back their use of PFHxA over the next five years.
In the U.S. only Michigan has a maximum contaminant level for PFHxA, specific to drinking water contamination, while several other states "have advisory or notification levels, or cleanup levels in groundwater, soil or fish tissue," Phil Brown, the director of the Social Science Environmental Health Research Institute at Northeastern University, told Newsweek.
"We should be concerned because this is a common replacement for PFOA which has many documented health effects," Brown said. "The general scientific consensus is that PFAS chemicals share many types of biological activity and many similar health effects."
What Smartwatch Producers Have Said
Smartwatches are a widely worn accessory in the U.S.—with around one in five Americans wearing either a smartwatch or wearable fitness tracker, according to a Pew Research survey from 2020.
Some of the major producers of smartwatches include Apple, Samsung and Google.
In light of the University of Notre Dame study published last year, a Google spokesperson told Newsweek: "Pixel Watch bands meet industry standards with regard to PFAS."
The spokesperson added that Google "proactively restricts" the chemicals in its products and is "committed to minimizing PFAS beyond what is required by law." Google imposes limits on a long list of different chemicals, PFHxA being one of them.
"We are proactively developing long-term alternatives to eliminate PFAS where possible," the spokesperson added.
Apple and Samsung have previously faced lawsuits concerned with this issue. A lawsuit was raised in U.S. District Court in the Northern District of California in January against Apple, with the claimant stating Apple "misleadingly and materially omits, on all relevant marketing and advertising, that the products contain toxic PFAS."
"Instead, [Apple] falsely and misleadingly markets and advertises its products" as "the ultimate device for a healthy life," the lawsuit added.
At the end of 2024, a lawsuit was filed in U.S. District Court in the Central District of California against Samsung, with claimants, represented by the same law firm, making similar accusations—that Samsung had "misleadingly" not disclosed that its products contained PFAS, despite its advertising its product would help consumers "start your wellness journey."
Both lawsuits point to the study released by the University of Notre Dame as proof the products "are toxic to consumers due to the presence of PFAS," adding that the "public was reasonably outraged, as widely reported in the press, when it was revealed that Defendant's products instead contain toxic PFAS chemicals that harm humans and the environment, and at excessive levels."
A Samsung spokesperson told Newsweek: "Customer safety and satisfaction are our top priorities. We remain committed to using safe and sustainable materials, while maintaining high-quality products."
Meanwhile, all materials used in Apple products, including materials with prolonged skin contact, must comply with the Apple Regulated Substances Specification—an additional specification created by the tech company that restricts certain hazardous substances in wearable devices, where consumer exposure is higher.
The company adheres to this specification when "regulatory limits are in general not available or may not be sufficiently protective for prolonged skin contact."
"Apple Watch bands are safe for users to wear," an Apple spokesperson told Newsweek. "In addition to our own testing, we also work with independent laboratories to conduct rigorous testing and analysis of the materials used in our products, including Apple Watch bands," they said.
Newsweek also contacted Huawei, another global producer of smartwatches, via email for comment.
A file photo shows various models of the Apple Watch Series 10 on display at the Apple Store on 5th Avenue in Manhattan.
A file photo shows various models of the Apple Watch Series 10 on display at the Apple Store on 5th Avenue in Manhattan.
Sven Hoppe/dpa via AP
Are Experts Concerned?
Although there are concerns over whether PFHxA can be absorbed through the skin there is currently limited research to determine whether this is the case, and, if so, how much of the chemical can be absorbed via this route.
"The skin provides a great barrier for chemical absorption but is also recognized as one of the major routes of absorption," Freeman said. "Some chemicals, depending on their chemical properties, can permeate the skin with the potential to enter the bloodstream and be distributed throughout the body."
"There are a small number of studies suggesting uptake of PFAS through skin is possible and the concentrations of PFHxA reported in the study are quite high," Christina Remucal, a professor of civil and environmental engineering at the University of Wisconsin-Madison, told Newsweek.
"It's also important to take into account that when people wear a watch, it's for most of their waking hours, so that is a lot of exposure," Brown said, advising consumers to opt for silicone-based bands instead.
However, Remucal added that "there is still a lot we don't know about uptake through skin compared to other pathways like drinking contaminated water."
Additionally, the way these samples were extracted "may not translate directly into human exposure," she said.
"More work needs to be done to better understand how PFAS in watch bands ultimately end up in our bodies," she said. "This study suggests looking at this potential pathway is important."
While data is "insufficient to conclude if wearing a smartwatch band containing PFHxA will be a significant concern as a PFHxA exposure source," Freeman recommended consumers err on the side of caution, and consider using a PFAS-free or silicone band in the meantime.
While caution and alternatives are advised, Haynes also told Newsweek there was no need for consumers to panic about the study.
"I am not worried about PFHxA exposure from the wristband of a smartwatch," she said.
She said that the chemical was likely incorporated "within a polymerized matrix and, thus, quite unlikely to leach from the band unless it is severely degraded by harsh conditions."
While there is some evidence that liberated PFHxA can be absorbed through skin, she said, "ingestion and inhalation of PFHxA are more significant routes for exposure and accumulation."
"If I had this smartwatch and the wristband was damaged, I would replace it, but I wouldn't think about it much beyond that," Haynes said.
That said, "In a world where I think we should only use PFAS in critical applications where there aren't other options, such as medical devices, I think companies should be working on an alternate formulation for the wristband," she added.
Reference
Alyssa Wicks, Heather D. Whitehead, Graham F. Peaslee (2024) Presence of Perfluorohexanoic Acid in Fluoroelastomer Watch Bands, American Chemical Society Environmental Science & Technology Letters Vol 12/Issue 1. https://pubs.acs.org/doi/abs/10.1021/acs.estlett.4c00907