Wearable Sensors for Detecting Biomarkers in Sweat: A Systematic Review

Sweat, as a readily collectible body fluid, contains key biomarkers such as metabolites, electrolytes, hormones, and neuromarkers that can reflect human health conditions. Real‐time noninvasive detection of these substances facilitates dynamic health monitoring and early‐stage disease alerting. From the very first lab‐based clunky electrophysiological signal recorder to modern wearable devices attached directly to human skin, significant efforts have been made to improve the sensitivity, portability, and reliability of sweat sensors. This article reviews the development of sweat sensing approaches, in a way through the functions and working mechanisms of the three core components: sweat absorption unit, sweat sensing unit, and signal processing and transmission unit. Signature advances in each component are elaborated, copicturing the progress pathway of the wearable sweat sensors, with particular emphasis on the sensing unit, which accounts for the most for the performance and application scenarios. A thorough discussion on the development trend and prospects of sweat sensing technology is also provided.