1. Primary objective: Determine if NR has an impact on the neurometabolic profile of patients with PD as measured by [18F]Fluorodeoxyglucose (FDG)-positron emission tomography (FDG-PET).
2. Secondary objective: Determine whether high dose oral NR improves motor symptoms associated with PD.
3. Tertiary objectives: determine whether high dose oral NR rectifies NAD metabolism and increases NAD levels in body fluids and muscle tissue.

Individuals with PD (n=30) will be recruited starting 14/02/2019 from the department of Neurology, Haukeland University Hospital. Only newly diagnosed and drug naïve PD patients are eligible for inclusion. After initial assessment at baseline, the participants will be randomly assigned (1:1) to one of two study groups (n = 15 per group): Nicotamide Riboside (NR) 500 mg x 2/day, or placebo. Participants and investigators will be masked to treatment group. Participants and investigators will be blinded (double blinded). The study will have a 4 week exposure period, during which patients will self-administer NR 500 mg x 2/day, or placebo per os. Patients will not be using any dopaminergic treatment during the study period. During baseline and 4 week follow-up, MDS-UPDRS will be performed as clinical measure. We will also collect blood, cerebral spinal fluid and muscle biopsy from all subjects at baseline and 4 week follow-up. Imaging will be performed using MRI, DAT Scan and FDG-PET at baseline and 4 week follow-up.

Inclusion Criteria:

1. Newly diagnosed with PD
2. Drug naïve with respect to dopaminergic treatment
3. Have a clinical diagnosis of idiopathic PD according to the MDS clinical diagnostic criteria for PD

Exclusion Criteria:

1. [¹²³I]FP-CIT single photon emission CT (DaTscan) does not show nigrostriatal degeneration.
2. Magnetic resonance imaging (MRI) suggestive of atypical parkinsonsism.
3. Dementia or other neurological disorder at baseline visit
4. Metabolic, neoplastic, or other physically or mentally debilitating disorder at baseline visit

Data will only be shared if there is scientific collaboration. Will not be publicaly shared.

All participants and investigators will be masked.