Rapid-onset anorectic effects of intranasal oxytocin in young men

Although the neuropeptide oxytocin exhibits many of the characteristics that would support its use as an anorectic agent for overeaters, studies of oxytocin's effectiveness at reducing eating in humans remain limited. In a double-blind, placebo-controlled crossover study, under the pretext of examining oxytocin's effects on various aspects of sensory perception, 20 men were given 24 IU of oxytocin and took a taste test of sweet, salty, and neutral snacks 45 min later. Participants self-rated appetite, anxiety, and other mood parameters, and then were left alone for 10 min with the pre-weighed snack food and invited to help themselves. To minimize the influence of hunger-driven eating, lunch had been provided immediately after oxytocin administration. In line with Ott et al. (2013), oxytocin significantly reduced the consumption of sweet foods; however, it also reduced consumption of salty snacks. Self-reported anxiety did not differ across drug conditions. The study is the first to demonstrate an effect of oxytocin on snack eating at 45 min post administration and on salty snacks. The anorectic efficacy of oxytocin after 45 min cannot easily be explained by the same mechanism as the one presumed to underpin its effects in previous studies that adopted much longer intervals between drug administration and testing.