The negative differential resistance (NDR) peak current observed in redox active self-assembled monolayer-based molecular junctions has been attenuated by controlling the composition of the molecular junction. Two approaches studied here include capping the electroactive ferrocenyl groups with beta-cyclodextrin and functionalizing the scanning tunneling microscope tip used to probe the self-assembled monolayer (SAM) with n-alkanethiols of different lengths. These are the first examples of systematic modification of the magnitude of the NDR response in a molecule-based system.