However, intravenous administration is not sustainable in the long term; thus, a controlled clinical trial administered oral doses of 6000 mg/day in individuals with Parkinson’s, where they observed blood increases in antioxidant capacity (GSH/GSSG and catalase), but not in GSH cerebral level, possibly reflecting the low oral bioavailability when compared to the intravenous application [78]. This evidence concerns the gene CAT and Parkinson disease.