<p>Many new drug trials fail to recruit participants that are representative of the populations they are intended to serve, resulting in research gaps which contribute to health inequalities. In the United Kingdom, reasons for non-participation in HIV drug trials remain poorly understood. Accordingly, we present a thematic analysis of interview and survey data gathering the perspectives of individuals who chose to participate and those who chose not to participate in the ILANA study – an implementation study of the first ever long-acting injectable HIV treatment, cabotegravir and rilpivirine. Drawing on the theoretical concepts of ‘biosociality’ and ‘therapeutic citizenship’, we identified three main thematic areas in participants’ narratives: solidarity with other people living with HIV; the pursuit of normality; and patient-clinician trust. We argue that our analysis offers insights into how decision-making across a diverse group of research participants can be motivated by similar factors but lead to different outcomes. This has implications both for how (non-)participation is understood by researchers, and how attentions may best be focused among those seeking to address inequity in research participation.</p>