A randomized placebo-controlled clinical trial of nicotinamide riboside in obese men: safety, insulin-sensitivity, and lipid-mobilizing effects.
Level 2 - randomized trial
Individual randomized controlled trial
PubMed 29992272 · doi:10.1093/ajcn/nqy132
What was done
In a double-blind, parallel-group randomized controlled trial, 40 sedentary men with obesity (BMI > 30 kg/m², aged 40–70 years) were allocated to receive either nicotinamide riboside (NR, 1000 mg twice daily; total 2000 mg/day) or placebo for 12 weeks. Researchers assessed insulin sensitivity via hyperinsulinemic euglycemic clamp, substrate metabolism with indirect calorimetry and isotope tracers (tritiated glucose and palmitate), body composition and fat distribution via DXA and MRI, and intrahepatic lipid content using MR spectroscopy.
What was found
The abstract does not report specific numerical values. NR supplementation showed no effect compared with placebo on insulin sensitivity, endogenous glucose production, glucose disposal, or glucose oxidation. NR also had no effect on resting energy expenditure, lipolysis, lipid oxidation, intrahepatic lipid content, or body composition. Safety blood tests were normal, and no serious adverse events occurred.
Why it matters
Despite promising preclinical evidence in animal models of obesity and diabetes, high-dose NR supplementation (2000 mg/day) over 12 weeks failed to improve insulin sensitivity or metabolic profile in obese human males.
Limits
The sample size was small (n = 40) and restricted entirely to sedentary, obese men aged 40–70 years, precluding generalization to women, non-obese populations, or individuals with diagnosed type 2 diabetes. Long-term effects beyond 12 weeks were not evaluated.
Cited by
- supports The 2018 Dollerup et al. trial of NR in older Danish men failed its primary endpoints of weight loss and insulin sensitivity, but showed a reduction in liver fat from ~21% to 11% (p = 0.13).