Twenty-one OMCLs from twenty countries participated in the first Market Surveillance on Suspected Illegal Products (MSSIP001). Participants were asked to analyse Slimming Dietary Supplements obtained from both the legal and the illegal supply chains and to report the presence of sibutramine and analogues as well as any other undeclared active ingredient possibly present in the samples and the estimated amount thereof, using methods of their choice. They were also requested to report additional information such as the product name, the manufacturer, the origin of the samples, the dosage form and strength, the batch number, the expiry date, the labelled APIs and the analytical method used. In total 370 batch samples were analysed. A summary of the results reported is given below.