In many countries, including Belgium and the Netherlands, dependence on benzodiazepines (BZDs) is a medical and social issue, and, for long-term users who want to taper off, doing so remains a personal challenge. For these users, online contexts such as forums can be a place to discuss this experience and look for practical and moral support among former users and fellow users trying to reduce or stop BZD use. This paper aims to shed light on the discourses of a Dutch-language benzodiazepine withdrawal forum, examining 133 forum threads (41,516 words). We take a corpus-based approach that combines frequency analyses with qualitative discourse analysis. We explore how the users extensively share lived, experiential knowledge of using and reducing medication and, in doing so, engage with domain-specific biomedical jargon. As such they discursively construct specialised expertise and a medical(ised), health professional-like expert identity, both in relation to their own situation, but also in interaction with other forum members, as advisors to each other. The forum thus not only serves as a site for emotional peer support, but also as a site for detailed informational support on tapering, which is traditionally offered by health professionals. This is especially pervasive, as many forum users also express indignation about the medical establishment and its lack of institutional knowledge support in the process of tapering off.