Safety and Metabolism of Long-term Administration of NIAGEN (Nicotinamide Riboside Chloride) in a Randomized, Double-Blind, Placebo-controlled Clinical Trial of Healthy Overweight Adults.
Level 2 - randomized trial
Randomized, double-blind, placebo-controlled clinical trial
PubMed 31278280 · doi:10.1038/s41598-019-46120-z
What was done
An 8-week randomized, double-blind, placebo-controlled clinical trial evaluated the safety, oral availability kinetics, and dose-dependency of nicotinamide riboside chloride (NR, NIAGEN) in overweight, but otherwise healthy adult men and women. Participants received placebo or daily oral NR at doses of 100 mg, 300 mg, or 1000 mg.
What was found
Oral NR significantly and dose-dependently increased whole blood NAD+ within 2 weeks by 22% (100 mg), 51% (300 mg), and 142% (1000 mg), along with increases in other NAD+ metabolites; these elevations were maintained throughout the 8-week trial. No flushing occurred, and adverse event frequencies showed no significant differences between NR doses or compared to placebo. NR did not increase low-density lipoprotein (LDL) cholesterol or disrupt 1-carbon metabolism.
Why it matters
It establishes human dose-response kinetics for oral nicotinamide riboside and provides safety and tolerability data up to 1000 mg daily over 8 weeks to inform dietary upper intake limits.
Limits
The abstract does not report the total sample size (n), precise statistical variance (standard deviations, confidence intervals, or exact p-values), or baseline participant demographics beyond being overweight. The study was limited to an 8-week duration in healthy overweight adults, leaving long-term clinical endpoints and safety beyond 8 weeks unassessed.
Cited by
- supports Clinical trials show that supplementing with NAD precursors NMN or NR can raise NAD levels approximately twofold in humans.