The authors compare the NMN-induced improvement in muscle insulin sensitivity with effects induced by (i) the once famous PPARγ agonist troglitazone, which was withdrawn from the market due to safety reasons, and (ii) 10% weight loss.1 However, the study was limited to postmenopausal overweight or obese women with prediabetes and, importantly, NMN, in contrast to a significant reduction in body weight, failed to reduce circulating insulin levels or liver fat. Here, INS is linked to prediabetes syndrome.