Significance: We introduce a soft, low-profile, intraoral electronics that offers continuous real-time monitoring of sodium intake via long-range wireless telemetry. The stretchable, hybrid electronic system integrates chip-scale components and microstructured sodium sensors with stretchable interconnects, together in an ultrasoft, breathable, microporous membrane. The quantitative computational and experimental studies of antenna performance optimize the wireless electronics, offering consistent functionality with minimal loss during multimodal deformation. Examples of in vivo study with human subjects demonstrate a highly sensitive, real-time quantification of sodium intake.