OXT and obesity due to melanocortin 4 receptor deficiency: From a glucose homeostasis standpoint, a single dose of IN oxytocin vs. placebo resulted in attenuated meal-associated glucose excursions in lean men and in non-diabetic individuals with class I obesity (mean BMI 32.10 ± 0.36 kg/m2) [222,223,236], but not in a group of non-diabetic men with a wide range of BMIs (18.5–40 kg/m2) [221].