Scientists warn your smartwatch strap may contain risky chemicals you wear all day
Smartwatches and fitness trackers have become everyday companions, tracking our steps, sleep and heart rate. Yet scientists are warning that the biggest health concern may not be inside the device, but on our skin.
New research points to potentially risky chemicals used in some popular watch straps. A study published in Environmental Science & Technology Letters examined 22 straps from smartwatches and fitness bands.
Researchers focused on materials such as silicone, leather, textile and fluoroelastomer, a high-performance synthetic rubber often marketed as durable and sweat-resistant.
According to physicist Grey F. Pikcilingis of Notre Dame of Maryland University, the team was surprised by how common PFAS-based materials were. These so-called forever chemicals are prized for repelling water and oil, yet they are notorious for persisting in the environment and the human body.
The analysis revealed that many fluoroelastomer bands contained perfluorohexanoic acid, or PFHxA. This compound does not readily break down under sunlight or in water, meaning it can accumulate over time.
PFHxA and related substances are being restricted in parts of the European Union due to growing toxicological concerns.
PFAS chemicals as a group have been associated in studies with increased cancer risk, high blood pressure, immune disruption and fertility problems. They are already found in non-stick cookware, water-repellent fabrics, cosmetics, furniture and some cleaning products.
Experts stress that the health risk from a single strap is still being evaluated. Actual exposure depends on factors such as how long the band is worn, whether the skin is sweaty or damaged, and how much of the chemical can migrate from the material to the skin.
However, scientists argue that constant wear on sensitive wrist skin justifies a precautionary approach. Many users, including children and pregnant people, wear these devices day and night, which can increase cumulative contact compared with other consumer products.
Regulators are gradually tightening rules around PFAS in consumer goods, but most smartwatch and fitness band makers are not required to list detailed chemical contents. That makes it difficult for consumers to know exactly what their strap contains.
Researchers advise users who are concerned to consider switching to alternative materials. Textile, leather or high-quality silicone bands without fluorinated coatings are generally seen as lower-risk options, especially for those with allergies or existing skin irritation.
Dermatologists also recommend simple hygiene steps, such as regularly cleaning the strap and wrist, and removing the device at night or during showers. If redness or rash appears under the band, temporarily stopping use and changing to a different material can help reduce potential exposure.
As wearable devices continue to spread, scientists say more transparent labeling and independent testing will be key. Until that happens, consumers may want to treat smartwatch straps not just as fashion accessories, but as products whose materials matter for long-term health.
