As a result of the research performed by the University of Antwerp (UA), the Iuliu Hațieganu University of Medicine and Pharmacy (UMF), and the National Institute for Criminalistics and Criminology (NICC) during the last few months, a wearable electrochemical platform based on a hollow microneedle (MN) array sensor for the monitoring of MDMA in the interstitial fluid by square-wave voltammetry has been developed, as well as a fast and simple method for the detection of four sinthetic cathinones based on their electrochemical profiles in a decentralized manner, and a fast, simple, and cost-effective electrochemical sensor used for the sensitive detection of methamphetamine in confiscated street samples with a complex matrix.