Interfacial tension gradients drive flow along fluid-fluid interfaces in a process known as the Marangoni effect. Such gradients can be caused by surfactants, as extensively studied in the literature. Less is known of its nanoscale behavior, where molecular interfaces exhibit specific properties such as interfacial viscosity. In this work we study the solutal Marangoni effect at a model fluid-fluid interface using molecular dynamics simulations. We show that molecular interfacial effects are important and should be accounted for in nanofluidic regimes. Hydrodynamic models can be extended with effective terms that include them.