An unambiguous substance definition is a prerequisite for deciding on appropriate regulatory options for a substance. In the REACH, CLP and Biocides Regulation, substances are defined by their manufacture, i.e. as "real substances". This definition includes all constituents of a substance that is in principle not manufactured as an "ideal substance" with a purity of 100 %. It has been shown that the real substance term alone is not sufficient to comprehensively regulate substances. In the following, the use of the two terms and the consequences in various areas of law will be examined in more detail.

English translation. German original version available: doi:10.21934/helpdeskfokus:reach20210210