October 9, 2026

@michaelokun

We had great hope for this Parkinson’s supplement. A randomized trial found it actually made symptoms worse. Nicotinamide riboside (NR) is a form of vitamin B3 that boosts NAD, a molecule essential for cellular energy production, mitochondrial function and brain cell health. There was considerable excitement that boosting NAD might protect dopamine-producing neurons and slow Parkinson’s disease. Brage Brakedal and colleagues describe in a new paper published in JAMA how this promising supplement performed in a large, randomized, double-blind, placebo-controlled Phase 3 clinical trial. Unfortunately, the results were not what we had hoped. Key points: - The NOPARK trial randomized 410 folks w/ early Parkinson’s disease at 11 centers in Norway to receive nicotinamide riboside (500 mg twice daily) or placebo for 52 weeks. - Parkinson’s symptoms actually worsened more in the supplement group. The total MDS-UPDRS score increased by 2.45 points in the NR group compared to a 0.27-point decrease in the placebo group, a statistically significant 2.72-point difference favoring placebo (P = .02). - Non-motor symptoms also worsened relative to placebo (4.22-point difference, P = .009). There was no significant benefit on dopamine transporter brain imaging, and the trial failed to demonstrate that NR slowed Parkinson’s progression. My take: This is a disappointing and important study. We had great hope for nicotinamide riboside because earlier studies suggested it could boost brain NAD, improve mitochondrial function and potentially protect vulnerable dopamine neurons. The biological rationale was compelling. However, when investigators conducted a rigorous year-long randomized trial, not only did the supplement fail to help, but folks taking it actually experienced statistically worse clinical outcomes. The average difference was modest and below the threshold generally considered clinically meaningful, but the direction of the results should get our attention. This is precisely why we need randomized trials and why we should be cautious about recommending supplements based on promising laboratory findings or small preliminary studies.