THE IMPACT OF BARIATRIC SURGERYON CORTISOL AND OXYTOCIN IN OBESE PATIENTS

Abstract

Morbid obesity is linked to widespread endocrine dysregulation, including heightened stress and responses and altered social-bunding signals. Cortisol, the primary effector of the hypothalamic-pituitary-adrenal (HPA) axis, drives insulin resistance and systemic inflammation, while oxytocin, a hypothalamic neuropeptide, influences appetite control, emotional coping and social behaviors. Although bariatric surgery is stablished as the most effective long-term treatment for severe obesity, its impact on these two pivotal hormones remains incompletely defined. Aim: To evaluate and compare plasma samples of cortisol and oxytocin concentrations in adults with morbid obesity before and three months after bariatric surgery, relative to healthy non-obese controls. Materials and methods: In this prospective longitudinal study, we enrolled 21 patients (age 25-60 years; Body Mass Index (BMI) ≥ 40 kg/m²) scheduled for either sleeve gastrectomy or Roux-en-Y gastric bypass, alongside 10 healthy volunteers (BMI 22 ± 1 kg/m²). Fasting blood samples were drawn on the morning surgery (T0) and at a three-month follow-up visit (T2). Plasma cortisol and oxytocin levels were quantified via high-sensitivity competitive immunoassays. Repeated-measures analyses compared hormonal shifts within the surgical cohort and against controls. Results: At baseline, patients exhibited markedly elevated cortisol (86.6 ± 50.2 ng/mL) and oxytocin (553 ± 115 pg/mL) compared with controls (54.3 ± 40.1 ng/mL and 380 ± 100 pg/mL, respectively). Three months following surgery, mean cortisol declined by 66% to 29.5 ± 22.4 ng/mL (p < 0.001), approximating control values, whereas oxytocin decreased modestly to 483 ± 120 pg/mL (p = 0.02), indicating partial normalization. The magnitude of cortisol reduction correlated strongly with the degree of weight loss and oxytocin adjustment aligned with patient-reported improvements in psychological well-being. Conclusions: Bariatric surgery elicits rapid and significant recalibration of both stress-related and social-bonding hormonal axes. The pronounced cortisol decreases and the trend toward normalized oxytocin suggest dual benefits, metabolic and psychological, in the early postoperative period. These findings support integrating targeted nutritional and psychological interventions to reinforce endocrine recovery and enhance long-term surgical outcomes.