To provide concentrated, low-viscosity liquid formulations of proteins, especially high-molecular-weight proteins, such as mAbs, capable of delivering therapeutically effective amounts of these proteins in volumes useful for SC and IM injections.SOLUTION : A liquid pharmaceutical formulation for injection comprises (i) antibodies, (ii) one or more viscosity-lowering agents, and (iii) a pharmaceutically acceptable solvent. When in a volume suitable for injection, the liquid pharmaceutical formulation has an absolute viscosity from about 1 cP to about 100 cP at 25癈 as measured using a cone and plate viscometer or microfluidic viscometer. The absolute viscosity of the liquid pharmaceutical formulation is less than the absolute viscosity of a control composition comprising the antibodies and the pharmaceutically acceptable solvent and not comprising the one or more viscosity-lowering agents, where each absolute viscosity is an extrapolated zero-shear viscosity.SELECTED DRAWING : None