The invention relates to a method for the electrochemical measurement of an analyte concentration in vivo, comprising a fuel cell with which the analyte to be measured is reacted catalytically with an enzyme contained in an enzyme layer and which supplies an electrical voltage, dependent on the analyte concentration to be measured, between an anode and a cathode, which voltage is measured. In the catalytic reaction of the analyte to be measured in the enzyme layer, a product is generated which, as fuel of the fuel cell, oxidizes on the anode and is reduced on the cathode. The invention further relates to a fuel cell for such a method.
