New Breathalyzer Device Tracks Fat Burning and Metabolism in Real Time

A portable breath-testing device developed by researchers at ETH Zurich measures fat metabolism in real time with an accuracy that approaches laboratory mass spectrometry, according to a validation study published in the journal Device. The hand-held unit detects acetone in exhaled breath, providing a non-invasive way for individuals and clinicians to monitor metabolic shifts during dieting, exercise, or therapeutic regimens without blood draws.

• The portable sensor measures acetone in exhaled air, serving as a reliable biological marker for fat oxidation rather than carbohydrate consumption.
• In a validation study of 12 adults published in Device, 312 breath readings matched lab blood tests and high-precision mass spectrometer results across various physical activities and diets.
• Developed by ETH Zurich researchers in collaboration with spin-off Alivion and University Hospital Zurich, the device utilizes a specialized gas sensor and filter mechanism to eliminate interfering compounds.

Clinical Validation and Breath Sensor Technology

The device operates similarly to standard law enforcement alcohol breathalyzers but targets volatile organic compounds associated with human energy expenditure. When the body shifts from burning carbohydrates like sugar to metabolizing fat stores, it produces acetone as a metabolic byproduct, which is subsequently expelled through the lungs. According to lead researchers, prior consumer breath-testing tools suffered from limited reproducibility and cross-reactivity with dietary substances. To overcome these barriers, the ETH Zurich team engineered an integrated gas filter designed to block interfering molecules. Additionally, a companion smartphone app guides users through standardized exhalation protocols. “The device measures the volume of exhaled air and only takes a sample that comes from deep in the lungs after a certain time,” explains lead author Simone Hersberger, noting that volume calibration tailored to individual lung capacity prevents sampling inconsistencies.

The underlying sensor technology builds upon more than a decade of development at ETH Zurich, originating from research that demonstrated extreme sensitivity capable of identifying single parts-per-hundred-million acetone concentrations. In the recent validation study conducted alongside University Hospital Zurich, researchers evaluated 312 discrete breath samples across 12 adult participants. Testing covered multiple metabolic scenarios, including periods of light and intensive physical activity alongside distinct dietary shifts. Results showed that the hand-held tool delivered readings practically identical to laboratory-grade mass spectrometry over a multi-month testing window.

Funding for the project was provided by Innosuisse, the Vontobel Foundation, and the Accentus Foundation. The technology has been commercialized under the trade name Nutrion by ETH spin-off Alivion AG and is currently deployed within international research studies and medical facilities.

Expanding Applications in Clinical Care and Therapeutics

With validation data established, researchers are investigating utility across several specialized medical frameworks, including individualized nutritional management and pharmaceutical interventions. “When it comes to diets, there’s no rule of thumb that works for everybody. Ideally, people should self-monitor to see how their own metabolism responds,” states Andreas Güntner, professor of molecular sensing at ETH Zurich’s mechanical and process engineering department. Researchers are particularly focused on applications where continuous metabolic tracking influences clinical outcomes, such as managing epilepsy via ketogenic diets or optimizing emerging weight management protocols. In partnership with the University Children’s Hospital Zurich, ongoing evaluations are assessing whether the tool can assist pediatric patients maintaining ketogenic therapy for seizure control. Similar tracking methodologies are under consideration for monitoring patient adherence and metabolic response during GLP-1 receptor agonist therapies.

Translating these diagnostic capabilities into routine outpatient practice requires close coordination with clinical dietitians and specialized pediatric or adult care teams. Alivion AG is actively seeking additional industry partners and strategic investors to scale manufacturing and expand regulatory pathways for broader clinical deployment.