DOPA DECARBOXYLASE INHIBITOR COMPOSITIONS

Disclosed herein are formulations containing carbidopa and optionally levodopa, arginine, and other components that have reduced levels of impurities and toxins, particularly degradation productions. Also disclosed herein are methods of treatment diseases or conditions relating to a loss of dopamine or dopaminergic neurons using such formulations, methods of making such formulations, and kits that include such formulations.