US Consumers Sue Oura Over Sleep Tracking Accuracy Claims

A class action lawsuit filed in San Francisco, California, on August 21, 2026, alleges that Oura's smart ring deceives consumers regarding the accuracy of its sleep tracking features. The suit, brought by Clarkson Law Firm, was filed on behalf of California resident Madison Thurber, who purchased a gold Oura ring in May 2025 for approximately $514, expecting to gain insights into her sleep. Thurber claims the device failed to deliver the advertised "unmatched accuracy" in recording sleep duration, nighttime awakenings, and sleep stage tracking.

The complaint notes that the medical community's gold standard for sleep staging is polysomnography (PSG), which uses professional equipment such as electroencephalography and electrooculography to measure brain activity, eye movements, and muscle tone. The Oura ring, worn on the finger, relies solely on peripheral physiological signals such as heart rate, body temperature, and blood oxygen, using machine learning algorithms to infer sleep stages. The lawsuit cites a study published in Nature, which collected data from 45 wearers over 45 nights, showing that the Oura ring achieved 53.18% accuracy in distinguishing between wake, light sleep, deep sleep, and REM sleep, while underestimating light and deep sleep durations and overestimating REM sleep. A study by the American Academy of Sleep Medicine found that 68% of sleep tracker users change their behavior based on device information.

Oura was valued at approximately $10.9 billion during its Series E funding round in September 2025.

In response, Oura stated it fully stands behind its scientific basis, research findings, and accuracy claims, citing numerous peer-reviewed independent studies confirming that different sleep stages produce unique, measurable, and reproducible physiological changes. The company acknowledged that the Oura ring is not a medical device and cannot fully replace clinical-grade sleep studies, but insisted its sleep staging algorithm has been validated in multiple studies. Oura noted that its algorithm development dataset includes over 1,200 nights of sleep data and that it has published peer-reviewed papers.

The company cited a study published in the journal Sensors in October 2024, which recruited 35 healthy adults aged 20 to 50 and compared the Oura Gen 3 ring with the Fitbit Sense 2 and Apple Watch Series 8. The results showed Oura's sensitivity for detecting sleep versus wakefulness was 95%, with accuracies of 79.5%, 77.0%, and 79.1% for distinguishing light, deep, and REM sleep, respectively. The Apple Watch Series 8 corresponding figures were 72.7%, 87.8%, and 77.7%. Oura said it disagrees with the allegations and will defend itself through legal channels.

Oura was founded in 2013 in Oulu, Finland, by Petteri Lahtela, Kari Kivelä, and Markku Koskela. In 2015, Oura raised funds via Kickstarter, reaching its $100,000 goal within 15 hours and ultimately raising over $650,000. In 2017, Stanford Research Institute purchased two rings without Oura's knowledge for independent testing, concluding that the Oura ring was among the most accurate wearable devices for measuring sleep quality and stages at that time, compared with the PSG gold standard. Since then, public endorsements from celebrities such as Lewis Hamilton, Gwyneth Paltrow, Prince Harry, Kim Kardashian, and Jennifer Aniston have further expanded the product's influence.