Inclusion Criteria:  Informed consent as documented by signature. Confirmed Parkinson's disease according to British brain bank criteria. Hoehn and Yahr Stage 0 - 2.5 on medication. Stable on PD treatment for a month at least. Absence of dementia confirmed by cognitive testing (MoCA >25).  Exclusion Criteria:  Contraindications to the class of drugs under study, e.g., known hypersensitivity or allergy to class of drugs or the investigational product. Women who are pregnant or breast feeding, or planning to become pregnant during the course of the trial or in the 3 months following the trial. Lack of safe contraception in women with childbearing potential Other clinically significant concomitant disease states (e.g., renal failure, hepatic dysfunction, cardiovascular disease, etc) that is not under stable control. Subject has an atypical parkinsonian syndrome or secondary parkinsonism. Patients with comorbidity that may interfere with the course of the trial.