The NAD Booster Nicotinamide Riboside Didn’t Slow Early Parkinson’s Disease

CATEGORY: BRAIN & MENTAL HEALTH

The supplement didn’t work. Nicotinamide riboside, a form of vitamin B3 sold around the world as an NAD booster, failed to slow early Parkinson’s disease in a year-long trial of 410 people. Those taking it actually finished about 2.7 points worse on the standard Parkinson’s symptom scale than those on placebo. The gap is statistically real but smaller than what a single patient would typically notice.¹

Why Hopes Ran So High

NAD is a molecule every cell uses to turn food into energy, and its levels sag in aging brains and in Parkinson’s. Nicotinamide riboside raises NAD, which is why it anchors a large market of supplements promising cellular rejuvenation. In 2022, the same Norwegian group behind this trial gave it to 30 people with Parkinson’s for a month. Brain NAD rose, and there were hints of clinical benefit.² That pilot is exactly why the big trial was run. The researchers went in with a strong biological case that the supplement would help.

One Year, Eleven Hospitals, Nobody Peeking

The follow-up, called NOPARK, gave 410 people with early Parkinson’s either 500 mg of nicotinamide riboside twice a day or matching placebo for 52 weeks. A lottery settled who got which, and neither patients nor their neurologists could tell. The main measure was the MDS-UPDRS, a clinician-scored checklist of movement and daily-life symptoms where higher means worse. A change of roughly 5 points is the usual bar for a worsening a patient would feel.

Scores Drifted the Wrong Way

After a year, the supplement group had worsened by 2.45 points while the placebo group held steady, an adjusted difference of 2.72 points in placebo’s favor (confidence interval 0.47 to 4.98).¹ Scores for non-movement symptoms, things like sleep, mood and digestion, ran about 4 points worse on the supplement. Brain scans of the dopamine system showed the disease advancing at the same pace in both groups, so the supplement didn’t appear to speed the biology up. It just didn’t help. Blood NAD rose as intended; NAD in the brain, measured at one year, didn’t budge. Serious adverse events were no more common on the supplement (8.3%, versus 14.1% on placebo).

What’s Left for the NAD Shelf

NAD boosters are marketed for aging, energy and brain health, and they remain easy to buy. This trial answers one question cleanly: in early Parkinson’s, a year of nicotinamide riboside at a substantial dose didn’t slow the disease, by symptoms or by scans, and the authors concluded the results don’t support it as a Parkinson’s treatment. Other claimed uses weren’t tested here. The capsules came from the supplement’s manufacturer, but public Norwegian research funds ran the trial, and the funders had no say in the results.

Key Takeaways

• A year of nicotinamide riboside, 500 mg twice daily, did not slow early Parkinson’s disease in a 52-week, double-blind trial of 410 people.
• Symptom scores ended 2.72 points worse with the supplement than with placebo, a statistically significant gap but below the roughly 5-point change a patient would usually feel.
• Dopamine brain scans progressed equally in both groups, and serious side effects were no more frequent on the supplement.
• The trial followed an encouraging 30-person pilot by the same team, a reminder that small early studies often don’t hold up at full scale.

References

1. Brakedal B, Skeie GO, Derad C, et al. Nicotinamide Riboside for Patients With Early-Stage Parkinson Disease: The NOPARK Randomized Clinical Trial. JAMA. 2026;DOI 10.1001/jama.2026.18828. link
2. Brakedal B, Dölle C, Riemer F, et al. The NADPARK study: A randomized phase I trial of nicotinamide riboside supplementation in Parkinson’s disease. Cell Metabolism. 2022;34(3):396–407.e6. link