NAD+ booster nicotinamide riboside did not help early Parkinson’s disease in a year-long phase 3 trial

Researchers at 11 centers in Norway randomized 410 adults with Parkinson’s disease diagnosed within the previous two years to oral nicotinamide riboside, 500 mg twice daily, or a matching placebo for 52 weeks. All had early-stage disease confirmed by dopamine transporter imaging and were on stable dopaminergic treatment. The primary outcome was the change in the total MDS-UPDRS score (parts I to III), a standard measure of Parkinson’s symptoms where higher is worse.

What they found

Among the 393 people in the primary analysis (mean age 65.6 years, 34% female), the total score rose by 2.45 points with NR and fell by 0.27 points with placebo. The adjusted mean difference was 2.72 points (95% CI 0.47 to 4.98; P = .02), favoring placebo. Four of the five key secondary outcomes showed no difference, but nonmotor symptom burden worsened more with NR (difference 4.22 points on the Non-Motor Symptoms Scale; 95% CI 1.07 to 7.37). Serious adverse events occurred in 8.3% of the NR group and 14.1% of the placebo group.

The nuance

The difference favoring placebo was smaller than the 5.2-point threshold the investigators defined as clinically important worsening, so the clearest message is no benefit rather than major harm. This was a trial in Parkinson’s disease, not in healthy older adults, so it does not directly test whether NR affects aging. It does weaken the case that boosting NAD+ alone protects the aging brain.

Youthful take

NR is sold in the US as a dietary supplement. It is not FDA-approved to treat or prevent any disease, including Parkinson’s, and no product is approved for aging. If you take an NAD+ booster or are considering one, review it with a physician who knows your health history and medications.