The invention relates to a sensor element (110) for detecting at least one analyte in a body or a body tissue (130), in particular for determining at least one metabolite concentration in a body fluid. Said sensor element (110) comprises an implantable, single-piece moulded body (112) which comprises a sensor end (114) and a coupling end (116). Said moulded body (112) comprises, in the region of the sensor end (114), at least one sensor area (118) which comprises at least one sensor material (122). Said sensor material (122) modifies, in the presence of the analytes, at least one optically measurable property. Said moulded body (112) also comprises at least one optically transparent coupling part (120) which is adapted to transmit electromagnetic radiation to at least one spectral range between the sensor area (118) and the coupling end (116). The moulded body (112) comprises, in the sensor area (118), at least one optically transparent matrix material (124). The analyte can at least partially diffuse through the matrix material (124) to the sensor material (122). The sensor material (122) is embedded in the matrix material (124). The coupling part (120) is at least partially formed by the matrix material (124).