Mental healthcare research increasingly focuses the needs of trans people and, in doing so, acknowledges knowledge and epistemic resources developed in trans communities. In this article, we aim to raise awareness of an ethical issue described by Emmalon Davis that may arise in the context of engaging with community knowledge and epistemic resources: the risk of epistemic appropriation. It is composed of two harms (1) a detachment of epistemic resources developed in the originating community and (2) a misdirection of these (...) epistemic resources for epistemic goals of a dominant community. In this article, we map and discuss the ethical concerns in using knowledge originating in trans communities in terms of epistemic appropriation in the context of mental healthcare research. We first argue that misgendering, failing to reference non-academic sources and a lack of attribution in community authorship are forms of epistemicdetachment. Second, we problematize cases of epistemicmisdirectionof trans epistemic resources, focusing on the examples of detransition and transition regret. We discuss harms related to epistemic appropriation in relationship to risks to safety. The article aims to raise awareness about the risk of epistemic appropriation both in researchers engaging with trans knowledge as well as in mental healthcare workers who seek information on trans. (shrink)