The General European Official Medicines Control Laboratory (OMCL) Network (GEON), co-ordinated by the European Directorate for the Quality of Medicines & HealthCare (EDQM), regularly organises market surveillance studies on specific categories of suspected illegal or illegally traded products. These studies are generally based on a combination of retrospective and prospective data collection over a defined period of time. This paper reports the results of the most recent study in this context with the focus on health products containing non-Anatomical Therapeutic Chemical-International Nonproprietary Name (ATC-INN) molecules. In total 1104 cases were reported by 16 countries for the period between January 2017 and the end of September 2019. The vast majority of these samples (83%) were collected from the illegal market, while only 3% originated from a legal source. For the rest of the samples, categorisation was not possible. Moreover, 69% of all the reported samples were presented as medicines, including sexual performance enhancers, sports performance enhancers, physical performance enhancers and cognitive enhancers or nootropic molecules that act on the central nervous system (CNS). Although the popularity of anabolics, PDE-5 inhibitors and CNS drugs in illegal products has already been reported, the study showed some new trends and challenges. Indeed, 11% of the samples contained molecules of biological origin, that is, research peptides, representing the second most reported category in this study. Furthermore, the study also clearly shows the increasing popularity of Selective Androgen Receptor Modulators and nootropics, two categories that need attention and should be further monitored.