The feminist movement has played a key role in challenging dominant modes of knowledge and expertise, revealing themasculine biases of allegedly objective knowledge and linking such biases to gendered power structures. In the field of health,the contestation of established medical knowledge and practices has also been centrally informed by the women’s healthmovement. In both the feminist movement more broadly and in the women’s health movement, women’s ‘lived experiences’have comprised an epistemic basis for building new knowledge challenging hegemonic perspectives. The use of women’scollectively processed personal experiences as an epistemic counter-authority has been most programmatically articulated inthe method of feminist consciousness-raising that was central in the 1970s’ second wave of feminism. Meanwhile, feministtheorists, especially of a poststructuralist or social constructionist orientation, have criticized naïve concepts of experience asa basis for knowledge claims, arguing that experiences are always culturally and discursively mediated in a way that rids themof their status as an unproblematic locus of truth.In this presentation we revisit feminist debates on the epistemic status of experience and its place in building counter-knowledges, through an analysis of group interviews (7) with and essays (23) written by women who claim or suspect thattheir use of copper IUDs has led to a range of systematic side-effects related to an excess of copper in their bodies. Thewomen, whose knowledge claims about the copper IUD are not supported by conventional medical authorities or healthcareinstitutions, were recruited from a Facebook group centred on the issue. We delineate the different ways that the womencollectively draw on their own experiences as a ground for building their counter-discourse, relating to previous theorizationsof feminist consciousness raising and feminist discussions of the relationship between experience and knowledge. However,we also show that the women’s invocation of experiential knowledge is complemented by other epistemic strategies bolsteringtheir knowledge claims. Finally, we seek to draw out the implications of our case analysis for epistemic debates in a ‘post-truth’ era, where subjective experiences as a counterforce to established expertise are used to advance both progressive andreactionary ends.