The differences in the pressure profiles between cis and trans membranes are clearest when evaluating the surface tension (Fig. ), as the trans membrane has a greater surface tension with more adhesive forces compacting the membrane. The average surface tension for cis and trans is observed to be 3.9 dyn/cm and 141.0 dyn/cm respectively. According to pressure there are significant differences in the attractive and repulsive contributions in cis and trans membranes which when converted into surface tension suggest that the trans membranes are far from relaxed (Fig. ). Previous experiments on membrane surface tension with pure PC and cholesterol inserted suggested that insertion of cholesterol increases the surface tension, 76 so seeing some difference is of course normal. Seeing a surface tension near zero for the cis membrane is also expected, as the CHARMM36 lipid parameters were explicitly designed around the goal of correcting for the inherent membrane surface tension that existed in prior membrane force fields. This raises the possibility that the high surface tension, and in particular its large magnitude, is an artifact of the force field being explicitly optimized for cis acyl tails that are the majority of lipids found in vivo. Thus, our explicit choice to create an all-trans membrane for comparison may simply be too far outside of what our current parameters can handle to yield a reasonable surface tension.