Nicotinamide Riboside for Patients With Early-Stage Parkinson Disease
A 410-person Phase 3 trial found no clinical benefit from the NAD+ precursor nicotinamide riboside in early Parkinson's disease.
TL;DR
- The NOPARK trial assigned 410 people with early Parkinson's disease to nicotinamide riboside or placebo for 52 weeks.
- Scores on the MDS-UPDRS worsened by 2.45 points with nicotinamide riboside, against little change on placebo; the adjusted difference was 2.72 points in favor of placebo.
- Investigators said the results do not support nicotinamide riboside as a treatment to slow Parkinson's disease. The trial does not answer whether NAD+ precursors help other conditions.
A Phase 3 trial of nicotinamide riboside, a precursor of nicotinamide adenine dinucleotide (NAD+), found no clinical benefit in early Parkinson's disease. The University of Bergen said the NOPARK study enrolled 410 participants at 11 centers in Norway. JAMA published the trial online on October 8, 2026, and its media notice said treatment for 52 weeks did not improve clinical outcomes and was associated with worse outcomes than placebo. [1, 2] [1] [2]
Participants received 500 mg of nicotinamide riboside twice daily or a matching placebo for one year, and neither they nor the study teams knew the assignment. Disease severity was measured with the MDS-UPDRS, on which a higher score means more pronounced symptoms. After 52 weeks, the nicotinamide riboside group had worsened by an average of 2.45 points, while the placebo group was essentially unchanged. The adjusted difference was 2.72 points in favor of placebo. [2] [2]
The university said the difference was statistically significant but modest, and below a commonly used threshold for a clinically important difference. Brain imaging showed no evidence that nicotinamide riboside slowed or accelerated changes in the dopamine system, and the overall rate of adverse events was similar in the two groups. Study director Charalampos Tzoulis said nicotinamide riboside increased NAD metabolism but that this did not translate into clinical improvement. [2] [2]
ChromaDex, a Niagen Bioscience company, supplied the nicotinamide riboside and placebo. The university said the funders had no role in the design, conduct, analysis, interpretation, or publication decision. The investigators said they do not recommend that people with Parkinson's disease use nicotinamide riboside or other NAD-boosting supplements outside controlled studies, and that the findings do not rule out a benefit in other diseases. Further subgroup analyses are still underway. [1, 2] [1] [2]
Why it matters
NAD+ precursors are both a supplement category and a drug-development hypothesis. NOPARK is a large placebo-controlled test of that hypothesis in early Parkinson's disease, and it separates a rise in NAD metabolism from a change in symptoms. For companies supplying these compounds, the trial narrows what a Parkinson's claim can rest on, without settling other indications.
Editor's note
Manual therapeutics brief. Trial dose and scores are reported as published; this is not a recommendation to start or stop any product. The investigators' statement about use outside trials is attributed to them.