Using an example of qualitative research embedded in a non-surgical feasibility trial, we explore the benefits of including qualitative research in trial design and reflect on epistemological challenges. We interviewed 18 trial participants and used methods of Interpretive Phenomenological Analysis. Our findings demonstrate that qualitative research can make a valuable contribution by allowing trial stakeholders to see things from alternative perspectives. Specifically, it can help to make specific recommendations for improved trial design, generate questions which contextualize findings, and also explore disease experience beyond the trial. To make the most out of qualitative research embedded in quantitative design it would be useful to (a) agree specific qualitative study aims that underpin research design, (b) understand the impact of differences in epistemological truth claims, (c) provide clear thematic interpretations for trial researchers to utilize, and (d) include qualitative findings that explore experience beyond the trial setting within the impact plan.