Flexible supercapacitors (FSCs) have received a lot of interest as portable power sources for wearable electronics. The biocompatibility of electrodes and electrolytes in wearable FSCs is important to consider although research into these topics is still in its early stages. In this work, we developed a wearable FSC that uses MXene Ti3C2 nanosheets and polypyrrole-carboxymethylcellulose nanospheres composite (Ti3C2@PPy-CMC) as the active electrode material and sweat as the electrolyte. The electrochemical performances of Ti3C2@PPy-CMC FSC were analyzed using an artificial sweat solution and exhibited excellent specific capacitance, power density, cycling stability, and bending stability. To demonstrate a real application of Ti3C2@PPy-CMC FSC, a sweat-chargeable FSC patch has been developed that can be applied directly to human clothing and skin to power a portable electronic gadget when the wearer is exercising. A comprehensive electrochemical study of the FSC patch was also conducted in various sweat secretion body regions such as the finger, foot sole, and wrist. Ti3C2@PPy-CMC composite's outstanding electrochemical performance indicates its potential capabilities and biocompatibility in wearable energy storage devices.