The development of guidelines on research ethics for social science and humanities (SSH) takes place in the scientific field, marked by disputes aimed at the establishment of hegemonic scientific standard. In Brazil, the National Health Council is responsible for approving these guidelines, which involve certain specificities. Based on the authors' experience in the SSH Working Group of the National Commission on Research Ethics (GT CHS / CONEP), this article presents the process of development of guidelines for SSH, and some its challenges: the distance between the statutory guarantee and the effective execution of guidelines; the biomedical hegemony and the marginal position of the SSH in the CEP / CONEP system; the inadequacy of the current resolution facing the research features in CHS; the use of the concept of risk in guidelines aimed at SSH in the health area. Some interfaces and tensions in the debate between scientific merit and ethical evaluation are also discussed. The analysis highlights important impasses and difficulties regarding inter-paradigmatic dialogue in health research, considered the characteristics of the different traditions, the CONEP's heavily relying on the positivist perspective and the defense of that paradigm hegemony.