Isocitric acid (Isocitrate), an isomer of citric acid, is a substrate for citric acid cycle and an endogenous metabolite, which has potential for the treatment of Parkinson’s disease, Fe-deficiency anemia, and metabolic myopathies associated with a shortage of succinate dehydrogenase and aconitate hydratase, as well as the mutation of the gene of NADP-dependent isocitrate dehydrogenase 1 (IDH1).