Previous work has shown that certain β(3)-peptides can effectively mimic the side chain display of an α-helix and inhibit interactions between proteins, both in vitro and in cultured cells. Here we describe a β(3)-peptide analog of GLP-1, CC-3(Act), that interacts with the GLP-1R extracellular domain (nGLP-1R) in vitro in a manner that competes with exendin-4 and induces GLP-1R-dependent cAMP signaling in cultured CHO-K1 cells expressing GLP-1R.