The present invention generally relates to a method of using NMR relaxation rates (R2) of water molecules as an indicator of the extent of aggregation of biopharmaceutical formulations. The biopharmaceutical can be evaluated nondestructively without the vial or container being opened or protective seal compromised (i.e., broken). The method is applicable to all biopharmaceuticals and the water signal obtained by magnetic resonance relaxometry is very strong and sensitive because water is used as the solvent and is present in high (>90%) concentrations in every biopharmaceutical formulation.