Wearable sweat sensor tracks vitamin levels in real time

By Vijay Kumar MalesuReviewed by Susha Cheriyedath, M.Sc.Apr 28 2026

A flexible skin patch detected trace vitamins in sweat and tracked changes in vitamin B9 after food and supplements, offering an early glimpse of non-invasive, personalized nutrition monitoring.

Study: Real-time nanomolar vitamin monitoring in sweat using an electrochemical skin-attached device. Image Credit: Image generated with AI 

In a recent study published in the journal Nature Communications, a group of researchers developed and validated a non-invasive wearable device capable of real-time monitoring of multiple vitamins in human sweat for personalized nutrition.

Wearable Sweat Vitamin Monitoring Background

Over 2 billion people worldwide suffer from “hidden hunger,” in which they get enough calories, but not enough micronutrients. This has serious health impacts, including anemia, weakened immune function, and developmental problems. Blood tests for vitamins are invasive, time-consuming, and do not allow for regular monitoring.

Recently, the development of wearable health technologies has changed how we monitor our physical parameters, but monitoring micronutrients is very difficult because they are present at low concentrations in accessible biofluids such as sweat. As such, a non-invasive, real-time approach would provide a new way to improve nutritional delivery. 

More research is necessary to support accurate, repeated vitamin assessments outside the clinical setting.

Wearable Electrochemical Vitamin Sensor Design

In the study, a wearable electrochemical sensing platform was used that could simultaneously and sensitively detect multiple vitamins in sweat.

The system comprised a patch that attached to the skin and flexed as the body moved, integrated with a reusable electronic device. It incorporated a screen-printed multiplexed electrode array for simultaneous detection of vitamins, pH, and ionic strength. 

Electrodes were enhanced with a nanocomposite of gold nanoflowers and sulfur- and nitrogen-codoped carbon to improve electron transfer and surface area for biomolecule attachment.

Antibodies and binding proteins specific to vitamins were immobilized on the electrode surface via chemical activation. Competitive binding assays were used, where sweat vitamins and enzyme-labeled vitamin analogs competed for binding sites, producing measurable electrochemical signals.

Sweat was induced noninvasively through iontophoresis using a mild electrical current and collected via a microfluidic system integrated into the patch. The device enabled real-time analysis of sweat composition, with embedded sensors that corrected for pH and ionic strength variations to improve accuracy.

Data collection and processing were done with a wireless system connected to a smartphone application. 

Validation involved comparisons with Enzyme-Linked Immunosorbent Assay (ELISA) measurements and testing in human participants under controlled dietary and supplementation conditions.

Although the platform was designed to detect six vitamins, the on-body human validation focused primarily on vitamin B9.

Sweat Vitamin Detection and Validation Results

The wearable biosensor can detect nanomolar levels of six essential vitamins (vitamin B1, vitamin B2, vitamin B7, vitamin B9 (folic acid), vitamin B12, and vitamin D) within the physiological range. The device achieved high sensitivity, with detection limits as low as 0.33 nanomolar for vitamin B9, performing favorably compared with many existing wearable sensors.

The nanocomposite electrode design significantly enhanced signal strength, enabling reliable detection even in the complex matrix of sweat.

The system was highly selective, as it differentiated target vitamins from other constituents found in sweat. Minimal cross-reactivity was observed, ensuring precise multivitamin monitoring. Reproducibility tests confirmed consistent performance across multiple devices, highlighting its scalability and practical usability.

In human trials, the device tracked changes in sweat vitamin B9 after food and supplement intake. After taking a 5 mg vitamin B9 supplement, vitamin levels in sweat increased by more than 3.6 times within hours of using the sensor, indicating that the sensor can measure rapid physiological changes. Dietary intake of foods rich in vitamin B9 also caused an increase in the amount of vitamin B9 in sweat.

A strong correlation between sweat and blood serum vitamin B9 levels was observed (r = 0.849), suggesting that sweat vitamin B9 may be useful for non-invasive trend monitoring of systemic vitamin status, although it is not yet clinically interchangeable with serum testing. Validation against ELISA measurements showed excellent agreement, with a correlation coefficient of 0.989 after calibration using pH and ionic strength data.

The study also revealed that different lifestyles were associated with differences in vitamin levels. For example, the biochemical effects of tobacco depend on nutrient metabolism, and smokers exhibited a lower concentration of vitamin B9 in both blood serum and sweat when compared with nonsmokers. This finding underscores the device’s potential for monitoring population-specific nutritional risks.

Additionally, the system showed stable performance in controlled on-body testing. For example, researchers collected sweat over multiple hours from several body sites while maintaining consistent performance.

The microfluidic design of the device enables efficient sweat collection and quick response times (within minutes). However, the human testing was preliminary and involved a small cohort of young adults, so larger and more diverse studies are needed.

Implications for Personalized Nutrition Monitoring

This study presents a promising step in non-invasive health monitoring by demonstrating a wearable device capable of real-time vitamin tracking through sweat. The platform could support personalized nutrition, as it is highly sensitive and can detect multiple analytes.

The technology is designed to measure multiple nutrients simultaneously and, with further validation and calibration, could help track vitamin trends and guide personalized nutrition strategies. 

Additionally, the information this technology provides about the effects of lifestyle habits (such as smoking) on vitamin levels could support public health initiatives. 

This new technology may eventually help shift how people assess vitamin status from occasional, periodic testing toward more frequent monitoring based on an individual's lifestyle and nutritional needs.