Presence of 4-Hydroxy- <i>N</i> -methyl- <i>N</i> -ethyltryptamine in Commercially Available Products

Novel psychoactive substances (NPS) remain an ongoing challenge for public health, forensic laboratories, and regulatory agencies, especially when they are chemically related to controlled tryptamines but are marketed as legal alternatives. In the United States, the Federal Analogue Act (FAA) was intended to restrict such substances; however, regulatory loopholes continue to be exploited. Herein, we present the characterization of a commercially available tablet marketed under the brand name Party Duck, alongside an unlabeled powder provided by our laboratory. Samples were analyzed using nuclear magnetic resonance (NMR) spectroscopy, gas chromatography/mass spectrometry (GC/MS), and liquid chromatography/mass spectrometry (LC/MS). All materials were identified to contain 4-hydroxy-<i>N</i>-methyl-<i>N</i>-ethyltryptamine (4-HO-MET), a synthetic psychedelic structure and pharmacologically similar to psilocin. The mean concentration of 4-HO-MET in the tablets was determined to be 2.82 or 1.45 mg/tablet, while the powder was confirmed qualitatively to contain the same compound. These findings demonstrate that 4-HO-MET is present in commercially available products and emphasize the importance of rigorous analytical methods for continuous monitoring of tryptamine derivatives in unregulated markets.