The Effects of Oxytocin in Obese Adults


This is a randomized, double blind, placebo-controlled study of the effects of intranasal oxytocin in obese adults, ages 18-45 years old. Subjects will be randomized to receive of intranasal oxytocin or placebo (3 sprays per nostril, 4 times per day) for 8 weeks. Study visits include screening to determine eligibility, a 2-part baseline visit, and visits every 2 weeks thereafter until week 14, with a safety follow-up visit 6 weeks after the last dose of study drug. Study procedures include behavioral, metabolic, neuroimaging, and endocrine assessments.

Full Title of Study: “A Randomized, Double-blind, Placebo-controlled Study to Evaluate the Effects of Repeat Doses of Intranasal Oxytocin in Obese Adults”

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: Randomized
    • Intervention Model: Parallel Assignment
    • Primary Purpose: Treatment
    • Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
  • Study Primary Completion Date: April 1, 2021


  • Drug: oxytocin nasal spray
    • oxytocin intranasal spray
  • Drug: Placebo
    • Placebo nasal spray

Arms, Groups and Cohorts

  • Experimental: oxytocin
    • oxytocin nasal spray (24 IU nasal spray, 4 times per day for 8 weeks)
  • Placebo Comparator: placebo
    • placebo nasal spray (4 times per day for 8 weeks)

Clinical Trial Outcome Measures

Primary Measures

  • Mean difference in weight loss between Oxytocin and placebo 8 weeks after Baseline
    • Time Frame: Baseline to 8 weeks
    • The difference between the mean weight loss values between Oxytocin and placebo-treated groups at 8 weeks after Baseline

Secondary Measures

  • Change in resting energy expenditure after 8 weeks of Oxytocin versus placebo
    • Time Frame: Baseline to 8 weeks
    • Change in resting energy expenditure from Baseline to 8 weeks in the oxytocin versus placebo-treated groups
  • Change in fat depots after 8 weeks of Oxytocin versus placebo
    • Time Frame: Baseline to 8 weeks
    • Change in fat depots from baseline to 8 weeks in the Oxytocin versus placebo-treated groups
  • Difference in caloric intake after 8 weeks of Oxytocin versus placebo
    • Time Frame: Baseline to 8 weeks
    • Difference in caloric intake after 8 weeks of Oxytocin versus placebo treatment, mediated by change in fMRI activation of reward-related food motivation brain areas and impulse control

Participating in This Clinical Trial

Inclusion Criteria

  • 18-45 years old;
  • BMI 30-50 kg/m2

Exclusion Criteria

  • Use of drug affecting metabolism, glucose, or appetite (Metformin is allowed if dose and weight are stable for at least 3 months);
  • history of medication changes within 4 weeks of enrollment;
  • active substance use;
  • history of cardiovascular disease, gastrointestinal disorders, bariatric surgery, epilepsy, untreated thyroid disease;
  • hematocrit >2% below normal;
  • fasting glucose > 125 mg/dL or hemoglobin A1c ≥ 7% ;
  • ALT or AST >2.5 times upper limit of normal;
  • Cr >1.5 mg/dL; hyponatremia;
  • pregnancy or breastfeeding;
  • unwilling to use medically acceptable form of contraception (females only)
  • follows a nonstandard diet (e.g., gluten free, pescatarian, vegetarian, vegan, Paleo, Atkins, raw diet, macrobiotic diet)
  • current smoking or tobacco use

Gender Eligibility: All

Minimum Age: 18 Years

Maximum Age: 45 Years

Are Healthy Volunteers Accepted: No

Investigator Details

  • Lead Sponsor
    • Massachusetts General Hospital
  • Provider of Information About this Clinical Study
    • Principal Investigator: Elizabeth Austen Lawson, Associate Professor of Medicine, Harvard Medical School – Massachusetts General Hospital
  • Overall Official(s)
    • Elizabeth A Lawson, MD, Principal Investigator, Massachusetts General Hospital
  • Overall Contact(s)
    • Kristine Hauser, MSN, 617-724-2235,

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