The present invention relates to a method for controlling a spectrometer for analyzing a product, the spectrometer including a light source including several light-emitting diodes having respective emission spectra covering in combination an analysis wavelength band, the method including steps of: supplying at least one of the light-emitting diodes with a supply current to switch it on, measuring a light intensity emitted by the light source by measuring a current at a terminal of at least another of the light-emitting diodes maintained off, determining, according to each light intensity measurement, a setpoint value of the supply current of each diode that is on, and regulating the supply current of each diode that is on so that it corresponds to the setpoint value.