You have probably seen the ads promising a boost in cellular energy and sharper years ahead.
NAD supplements have become one of the hottest wellness categories in the US, built on the idea that you can top up a molecule your cells make less of with age.
Now the biggest clinical test yet of one of these compounds has delivered a flat miss.
A yearlong Phase 3 trial of nicotinamide riboside, published October 8 in JAMA, found no clinical benefit in people with early Parkinson's disease.
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The NOPARK trial enrolled 410 people recently diagnosed with Parkinson's.
It was led by researchers at the University of Bergen and Haukeland University Hospital in Norway. Half took 500 mg of nicotinamide riboside twice a day. Half took a placebo.
After 52 weeks, the group on the supplement had actually gotten slightly worse than the placebo group on the standard Parkinson's severity scale.
Why so many people take this supplement
Nicotinamide riboside, usually called NR, is a form of vitamin B3. It is sold under brand names like Tru Niagen and marketed to raise cellular NAD, a molecule tied to energy production and DNA repair that drops with age.
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NAD precursor supplements, which also include NMN, have become a fast-growing wellness category. Marketing promises range from more energy and better focus to slower aging and stronger brain health.
What the trial actually measured
The researchers used a standard Parkinson's score called the MDS-UPDRS, which rates symptoms across daily life, mental state and movement. Lower scores are better.
Over the year, the NR group climbed 2.45 points on that scale. The placebo group barely moved, dropping 0.27 points.
The adjusted gap of 2.72 points favored placebo. The difference was statistically significant but small enough to fall below the threshold most doctors consider clinically meaningful.
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Brain scans showed no sign that NR slowed or sped up the loss of dopamine-producing cells, the biological hallmark of Parkinson's. Side effects were similar in both groups.
What the finding does and does not say
Professor Charalampos Tzoulis, the trial's director at the University of Bergen, said the compound did raise NAD metabolism as intended. The problem is that the extra NAD did not translate into any clinical gain for patients.
The researchers wrote that the result does not support using NR to slow Parkinson's disease. They advised against taking NR or other NAD boosters for Parkinson's outside controlled trials.
The trial tested one compound in one disease. It did not look at NMN, the other major NAD precursor on the market, and it did not test the broader anti-aging or energy claims made in healthy adults.
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For people with Parkinson's considering NR, the message is specific. In the largest randomized trial done so far, 500 mg twice a day for a year did not help. The group taking it fared slightly worse than the group on placebo.
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This article is made and published by Ida-Marie Palm Varbæk, who may have used AI in the preparation.