Because of extensive potential applications in health fields, the wearable self-driven sensor is an indispensable part for next-generation medical systems. In this paper, a wearable self-driven sensor utilizing a lift-off (In,Ga)N film is proposed and demonstrated successfully. (In,Ga)N film is separated from an epitaxial silicon substrate through an economical and fast electrochemical etching procedure. With good flexibility, the self-driven sensor can continuously monitor localized sweat and sweat electrolyte concentration. Hence, it can monitor the electrolyte loss in human body, which is crucial to facilitate proper fluid replenishment for people during exercise. Furthermore, the sensor maintains stable detection performance under different bending conditions, indicating the good stability. Therefore, this study holds great potential for the advancement of wearable devices for personalized health management requiring ultra-low energy consumption.