Psychedelic Drug Checking: Analytical and Strategic Challenges in Harm Reduction for Classic Psychedelics

Classic psychedelics such as LSD, psilocybin, and DMT from unregulated markets pose considerable risks through unknown adulterants and potencies. In this chapter, we explore the importance of drug checking in minimizing harm among users of classic psychedelics and examine the opportunities and challenges associated with intervention settings, analytical techniques, and risk communication strategies. Gas chromatography (GC) and liquid chromatography (LC) coupled with mass spectrometry (MS) provide the most reliable and comprehensive analysis results for classic psychedelics. However, they are relatively costly, stationary, and require legal permission to obtain reference standards. Combined presumptive tests, such as thin-layer chromatography (TLC) and reagent testing, offer a time-efficient and cost-effective approach to initial substance screening. For certain compounds, Fourier-transform infrared spectroscopy (FTIR) serves as a valuable complementary technique, although potent psychedelics, such as LSD and NBOMe on blotter paper or in diluted solution, and complex botanical matrices challenge its detection limit, requiring the use of multiple analytical methods to confirm results. Such combination can effectively prevent acute risks, while confirmatory instrumental analysis remains essential for ongoing monitoring and public health efforts. Alongside robust testing procedures, drug checking's consultative component is crucial for clarifying analytical constraints, promoting safer use practices, and offering referrals to health services. By identifying mislabeled samples and ensuring tailored risk communication, drug checking not only protects individual users but also informs the public and health professionals regarding dangerous or novel substances. This chapter situates drug checking as a key public health measure that reduces acute harm from misrepresented psychedelic substances while supporting monitoring efforts.