BackgroundPreclinical studies suggest that the neuropeptide oxytocin reduces food intake and body weight, but only a few clinical studies have investigated the translatability of these findings in humans. The present study investigated the safety and efficacy of oxytocin nasal spray in patients affected by binge eating disorder and obesity. MethodsSeventeen outpatients affected by binge eating disorder and obesity participated in a 8 week double-blind trial and received oxytocin (n=8; 24 IU, four times a day, 20 min before each of three meals and before going to bed) or placebo (n=9) with an energy-restricted diet. Primary outcomes included adverse events and the number of binge eating episodes per week. Secondary measures included body weight, BMI, severity of BED, craving for food, quality of sleep, quality of life, anxiety, and depressive symptoms. ResultsOne patient of oxytocin group discontinued prematurely the trial before the first post-randomization efficacy measure. Among the other 16 participants, 13 (81.2%) completed the trial, and 3 (18.8%) discontinued [3 in the oxytocin group; 0 in the placebo group (p=0.0625, Fisher's exact test)]. No significant difference between groups was found in any outcome evaluated. Patients of the placebo group performed slightly better than patients of the oxytocin group in some secondary outcomes, but these differences were not significant. ConclusionOxytocin nasal spray resulted to be safe, including in women of childbearing age but did not significantly reduce the number of binge eating episodes per week in outpatients affected by binge eating disorder and obesity. These findings are discussed in light of the human oxytocin literature.