<p>The Research Ethics Committee (REC)/National Commission of Research Ethics (CONEP) System has overseen human research in Brazil for almost three decades. Since its inception, this system aimed to encompass biomedical and non-biomedical sciences. However, this integration of two distinct research cultures is sought within a complex ethics regulatory framework. This framework primarily guides the review of health sciences research, embedding aspects of the social sciences and humanities (SSH). We explored this phenomenon through a survey conducted in 2024 using a sampling frame of 864 RECs identified in late 2021. The survey was delivered prior to the enactment of Federal Law 14874 (May 2024). The instrument was discussed and validated by an expert panel before delivery in May 2024, with a final response rate of 27 %. Our results reveal the nuanced intricacies of RECs operating at the intersection of biomedical and non-biomedical sciences, just before ethics review became legally binding for all human research in the country. Our analysis underscores the necessity of integrating an SSH framework to ensure comprehensive review processes that account for the social and cultural complexities inherent in human research, including global health studies. Overall, our results indicate that the system, traditionally working within a sub-legal normative structure, was already grappling with significant challenges before Law 14874/2024. Looking ahead, the question of how to effectively regulate human research in Brazil within a new context and national system is becoming increasingly pressing. Given SSH’s crucial role in global health research, it is timely for the research community to closely observe and proactively respond to how this situation unfolds in Brazil.</p>