In mid to late May 2026, we tested a number of substances of particular health concern. In most of the cathinones submitted for analysis, one or more other cathinones were detected than expected, including in particular 4-CMC (4-chloromethcathinone). Furthermore, in a sample submitted for analysis as fentanyl, in addition to two previously unidentified opioids[1] which is many times more effective Carfentanil detected. A tablet submitted for analysis as ecstasy showed a unknown substance .

Under the following link, all samples that have been analysed by checkit! since the last warnings and classified as high-dose, unexpected or of particular health concern are presented in detail: Current warnings KW 23 - 2026