The article discusses some of the problematic aspects of the investigation of fraud in the sale of "functional products", one of which is biologically active food additives. The implementation of such products is carried out with the use of aggressive forms of marketing with a psychological impact on people of old age and other segments of the population who need additional social protection. The choice of this issue is due to the intensification of the law enforcement struggle in this direction, however, the investigative tools for proving the guilt of those engaged in fraudulent activities in the sale of dietary supplements should be expanded. Key words: forensic science, forensic examinations of the investigation of fraud in the consumer market, criminal sale of “functional products”, consumer fraud in the sale of dietary supplements.