Dollerup OL, et al. - In this investigator-initiated randomized, placebo-controlled, double-blinded, and parallel-group designed clinical trial, researchers investigated whether dietary nicotinamide riboside (NR) supplementation over a 12-wk period in obese, insulin-resistant men is safe and if it could potentially improve insulin sensitivity and other metabolic parameters in these subjects. They randomly assigned 40 healthy, sedentary men with a body mass index (BMI) > 30 kg/m², age-range 40–70 y to 12 wk of NR (1000 mg twice daily) or placebo. Findings suggested safety of 12 wk of NR supplementation in doses of 2000 mg/d, however, no improvement was seen in insulin sensitivity and whole-body glucose metabolism in obese, insulin-resistant men.