There are all kinds of anti-aging products and supplements for sale. One hot trend is NMN supplements that are advertised by many companies at a range of affordable prices. Shin-ichiro Imai, MD, PhD, at Washington University School of Medicine in St. Louis, is a leader on NMN research. His mouse-based research indicates NMN can slow signs of aging, boost energy and rejuvenate metabolism. But when it comes to supplements on the market, Imai advised caution, “As far as I can tell, there are only two sources on NMN which have been extensively tested in both rodents and humans.” Imai is conducting a human clinical study at the School of Medicine. “We need to prove the efficacy scientifically in human clinical trial,” he said.