Study Details & Results
This was a small human study, in which NR was administered orally at 500 mg, 2x per day, for a total of 6 weeks.
Researchers analyzed plasma samples and measured levels of NAD+ and NADH in neuronal extracellular vesicles (NEVs).
- NAD+ levels in neuronal NEVs were significantly higher after 6 weeks of oral NR supplementation compared to placebo
- There was a marked decrease in Aβ42, which is a component of amyloid plaques, associated with Alzheimer’s
- This was the first time researchers had evidence that NR reaches the brain, improving neuronal NAD+ levels.
“But until now, it was unknown whether NR reached targeted organs like the brain to have a real therapeutic effect,” according to Christopher Martens, one of the key researchers in this study, and the director of the Delaware Center for Cognitive Aging Research. Source: Researchers link supplement to reduced biomarkers of Alzheimer’s in the brain
Nicotinamide Riboside Bioavailability
NR has been shown to increase the lifespan of all species tested to date, including mice. (1,2,3).
However, NR is not stable in circulation and degrades in plasma. NR disappears from the bloodstream and is almost undetectable 45 minutes after injection at 50 mg/kg. (4)
In humans, NR is never found at more than trace levels in blood plasma (5). After oral supplementation of 1,000 mg per day for 3 weeks, NR was not increased at all and was barely detectable (6).
Therefore, a more effective delivery method is necessary to overcome the numerous instability and absorption issues of NR.