The consumption of illicit drugs is deemed both politically and epistemologically problematic due to social stigma and legal frameworks, making scholars’ first-hand involvement in drug research widely contested. In this sense, prohibition not only restricts users; it also shapes how—and whether—researchers can engage with certain forms of knowledge at all. Yet many scholars ask whether it is possible to conduct profound research on psychoactive substances without experiencing their embodied effects. Drawing on ethnographic research in Brazil, I discuss participation in “ayahuasca” rituals as both a condition of access to studied groups and a mode of knowledge production. I argue that methodological choices in drug studies are inseparable from wider structures of power: shaped not only by law and academic institutions but also negotiated in the field. This entanglement with power generates epistemic peripheries: spaces where knowledge is marginalized as it moves between regimes of legitimacy.