Oxytocin and Body Weight Homeostasis — Wrong Hypothesis or Wrong Methodology?

The diverse roles of the hormone oxytocin in physiological homeostasis, milk let-down, maternal and social affiliative behaviors, emotion regulation, and cognition have been studied across various disciplines.1 Among them, preclinical studies have demonstrated an effect of oxytocin on ingestive behaviors. In this issue of NEJM Evidence, Plessow et al.2 report results of a well-designed, randomized, double-blind, placebo-controlled clinical trial to evaluate the effects of intranasal oxytocin (24 IU daily in divided doses) on weight loss in participants who are obese. Despite extensive preclinical studies demonstrating that oxytocin reduces food intake3 and preliminary clinical trials supporting the potential use of oxytocin as an antiobesity medication in humans.