SecinH3 is a cell-permeable triazolo compound that acts as a Sec7 domain-binding (Kd ≤250 nM for Sec7 from human cytohesins 1-3), selective antagonist against cytohesin family small nucleotide exchange factors, or GEFs (IC50 ≤5.6 μM in ARF1 GDP/GTP exchange assays using human cytohesin 3, as well as murine and Drosophila homologues). SecinH3 inhibits large GEFs only at much higher concentrations (IC50 ≥65 μM in GDP/GTP exchange assays using hEFA6-S7 and yGea2-S7) and exhibits little activity against a panel of 10 commonly studied kinases or hSosII. SecinH3 was shown to effectively inhibit insulin signaling both in HepG2 cells in vitro and in Drosophila and mice in vivo. SecinH3 is an inhibitor of cytohesin-1, cytohesin-2 and GRP1.