Parkinson’s disease (PD) is a major cause of death and disability, and current treatments can provide partial symptomatic relief, mainly for motor symptoms but make no substantial impact on disease progression. A growing body of evidence supports that boosting cellular levels of nicotinamide adenine dinucleotide (NAD) may confer neuroprotective effects in both healthy aging and neurodegeneration. The primary aim of this study was to assess penetration and metabolic responses of the brain to nicotinamide riboside (NR) supplementation in patients with PD. This study is a double-blinded, randomised, placebo-controlled phase I study of NR in newly diagnosed PD patients, naïve to dopaminergic therapy. Participants (n=30) where randomly assigned (1:1) to one of the two groups: NR group or placebo group. Results show that: - oral NR therapy increases brain NAD levels and impacts cerebral metabolism in PD. - supplementation with NR may target multiple processes implicated in the pathophysiology of the disease by upregulating the expression of genes involved in mitochondrial respiration, oxidative damage response, lysosomal and proteasomal function and downregulating inflammatory cytokines in the central nervous system. Authors conclude that NR can be a potential neuroprotective agent against PD. However, further investigation in a larger trial is required to warrant these findings.