This report presents the findings from our researcher workshop focused on understanding the user requirements for synthetic data developed from sensitive data within Trusted Research Environments. Through a series of structured discussions with researchers, we explored how synthetic data could support various research activities, identified key use cases, and gathered insights into the characteristics, access needs, and governance models necessary to ensure synthetic data is both useful and responsible. These outcomes will inform the development of practical guidance and future stakeholder engagement to advance the safe and effective use of synthetic data in UK research.