If you saw headlines about the new NAD Parkinson's study, the 410-person NOPARK trial found no clinical benefit. As of October 17, 2026, the day this article was written, the phase 3 NOPARK trial in JAMA reported no symptom benefit. Published online on October 8, 2026, it tested oral nicotinamide riboside (NR), an ingredient the body uses to make NAD.
In 410 people with early Parkinson's disease, taking 500 mg twice daily for 52 weeks worked no better than placebo. A University of Bergen release noted that swallowing NR capsules raised blood NAD metabolism, yet symptoms did not improve. Because NOPARK tested oral capsules rather than injected NAD+, it neither supports using injections for Parkinson's disease nor measures what an injection does.
What the NAD Parkinson's trial tested and found
NOPARK enrolled 410 adults aged 35 and older across 11 Norwegian centers, coordinated by Haukeland University Hospital. The trial was double-blind, according to the ClinicalTrials.gov record.
The University of Bergen release identifies ChromaDex as the supplier of NR and placebo. Every participant had been diagnosed within the past two years and already took optimized standard Parkinson's medication.
To enter, patients needed a score below 3 on the Hoehn and Yahr scale, which stages how far movement symptoms have spread. They also needed a baseline brain scan showing reduced dopamine-transporter activity, a hallmark of Parkinson's disease. The trial excluded people with dementia, atypical or vascular parkinsonism, high-dose vitamin B3 use within 30 days, or genetically confirmed mitochondrial disease.
Participants took 500 mg of oral NR capsules or placebo twice a day for 52 weeks. Doctors tracked parts I through III of the Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS), a 0-to-236 symptom and function exam. On that scale, higher scores mean worse symptoms.
In the primary analysis of 393 people, adjusted scores got worse by 2.45 points on NR. Placebo scores stayed essentially flat at −0.27 points after one year. That left an adjusted mean difference of 2.72 points (95% CI, 0.47 to 4.98; P = .02) favoring placebo.
What the NOPARK trial results mean in everyday terms
| Measure | Oral NR (500 mg twice daily) | Placebo |
|---|---|---|
| Randomized | 206 | 204 |
| Primary-analysis population (total 393) | 199 | 194 |
| Week-52 adjusted MDS-UPDRS change (95% CI) | 2.45 (0.80 to 4.10) | −0.27 (−1.95 to 1.40) |
| Any adverse event (safety n = 205 per arm) | 112 (54.6%) | 110 (53.7%) |
| Serious adverse event | 17 (8.3%) | 29 (14.1%) |
| Severe adverse event | 20 (9.8%) | 32 (15.6%) |
The average 2.72-point difference was below commonly used thresholds for a clinically important change, but that does not describe every participant's experience. The difference met the study's statistical significance threshold (P = .02), but statistical significance does not measure its importance in daily life. Those usual MDS-UPDRS cutoffs are 6.7 points for improvement and 5.2 points for worsening.
On the Non-Motor Symptoms Scale (NMSS), symptoms worsened more with NR than placebo. The adjusted difference was 4.22 points (95% CI, 1.07 to 7.37; P = .009). Four other key secondary outcomes showed no significant difference, and staying below the 5.2-point cutoff does not mean NR matched placebo.
Worse symptom scores also do not prove that nerve cells died faster. Brain scans of the dopamine system detected no significant difference between groups, though one-year imaging cannot rule out small effects. Exams were done while patients took their regular Parkinson's drugs without a washout.
Oral NR increased blood NAD metabolism. At 52 weeks, the brain NAD measurement relative to ATP-α, an energy-related molecule, did not differ significantly between groups.
Higher blood markers did not lead to better symptoms, a pattern we explore in common myths about NAD+. Based on these results, the University of Bergen researchers advise against taking NR or other NAD-boosting supplements for Parkinson's disease outside clinical studies.
Why earlier nicotinamide riboside Parkinson's studies looked different
Why did scientists run a 410-person trial in the first place? NOPARK followed the 2022 NADPARK study in Cell Metabolism, a 30-day phase I pilot of 30 newly diagnosed, unmedicated patients. Those patients took 1,000 mg of oral NR or placebo daily for a month.
The short pilot was well tolerated and showed a significant but variable rise in brain NAD and spinal-fluid metabolites. Among participants whose brain NAD rose, shifts in brain metabolism lined up with mild symptom improvement.
A second four-week pilot, the 2023 NR-SAFE trial in Nature Communications, tested 1,500 mg twice daily in 20 people (10 per arm). All 20 participants completed the trial, and blood NAD rose in the NR group.
No moderate or severe adverse events were reported, though levodopa timing may have affected the exploratory symptom finding. The authors strongly discouraged taking 3,000 mg daily outside monitored studies, and neither four-week pilot could prove lasting benefit.
Oral NR capsules vs. compounded NAD+ injections
If you are comparing an NAD supplement Parkinson's study with NAD+ injections, the boundary between them matters. NOPARK tested swallowed capsules of nicotinamide riboside, an ingredient the body uses to make NAD. It did not test NAD+ itself, injections, intravenous drips, nicotinamide mononucleotide (NMN), or any compounded medication.
Because both the molecule and the delivery route differ, oral NR's score change cannot be assigned to an injection. NOPARK provides no clinical evidence that NAD+ injections help people with Parkinson's disease.
Under federal law (DSHEA), the FDA's dietary supplement Q&A explains that the agency does not approve supplements before sale. Seeing an NR bottle on a store shelf is not FDA approval. Likewise, there is no FDA-approved NAD+ drug for Parkinson's disease.
NAD+ prescribed through Promise is dispensed by a licensed U.S. compounding pharmacy. It is prepared as a compounded medication, which is different from an FDA-approved product: the formulation offered here is not FDA-approved. As the FDA's compounding Q&A notes, the agency does not verify the safety, effectiveness, or quality of compounded drugs before marketing.
Our September 2026 NAD+ update covered a February 9, 2026 warning letter where a repackager had no FDA-approved applications for NAD+ 50 mg/mL. A July 27, 2026 close-out letter closed those inspection violations and did not grant FDA approval to any medication.
Even though compounded NAD+ is not FDA-approved, a licensed provider may still prescribe — that decision is between you and your doctor. At Promise, a licensed provider reviews every request and not everyone qualifies.
A prescribed route adds a named clinician, an identified licensed U.S. compounding pharmacy, a labeled lot and a contact for reporting problems. A vial obtained without a prescription leaves out that prescribing review. These safeguards do not establish Parkinson's benefit or guarantee that a preparation is risk-free.
Safety findings and what to watch next
NOPARK tracked adverse events—health problems reported during the study—in 205 people per group, classified by the treatment they actually received. Overall rates looked similar: 112 people (54.6%) on NR and 110 (53.7%) on placebo reported at least one event. Serious adverse events occurred in 17 people (8.3%) on NR versus 29 (14.1%) on placebo.
Severe adverse events were tracked separately and occurred in 20 people (9.8%) on NR versus 32 (15.6%) on placebo. Similar overall totals do not mean that serious medical events were absent. If you think a dietary supplement caused harm, the FDA advises contacting or seeing your healthcare provider immediately.
Injectable NAD+ carries separate preparation risks that have nothing to do with oral NR capsules. In an October 30, 2024 compounding alert, the FDA reported severe chills, shaking, vomiting, and fatigue—some requiring medical treatment—after injectable NAD+ drugs. The FDA said these reactions were consistent with excessive endotoxins, bacterial material that can cause illness.
Food-grade ingredients can pose contamination risks when used without appropriate processing. Meanwhile, the NOPARK team plans further biological and subgroup analyses, though no benefit has been reported from that work. Anyone with Parkinson's disease should keep their neurology care plan and can review our questions to ask before starting NAD+.
