The increasing complexity of human subjects research and its oversight has prompted researchers, as well as institutional review boards, to have a forum in which to discuss challenging or novel ethical issues not fully addressed by regulations. Research ethics consultation services provide such a forum. In this article, we rely on the experiences of a national Research Ethics Consultation Collaborative that collected more than 350 research ethics consultations in a repository and published 18 challenging cases with accompanying ethical commentaries to (...) highlight four contexts in which REC can be a valuable resource. REC assists: 1) investigators before and after the regulatory review; 2) investigators, IRBs, and other research administrators facing challenging and novel ethical issues; 3) IRBs and investigators with the increasing challenges of informed consent and risk/benefit analysis; and 4) in providing flexible and collaborative assistance to overcome study hurdles, mediate conflicts within a team, or directly engage with research participants. Institutions that have established, or plan to establish, REC services should work to raise the visibility of their service and engage in open communication with existing clinical ethics consult services as well as the IRB. While the IRB system remains the foundation for the ethical review of research, REC can be a valuable service for investigators, regulators, and research participants aligned with the goal of supporting ethical research. (shrink)