This is a single-center, randomized, participant-blinded, sham-controlled trial designed to evaluate the adjunctive effect of transcutaneous auricular vagus nerve stimulation (taVNS) in overweight or obese patients who show a suboptimal weight-loss response to incretin receptor agonist therapy. A total of 24 participants will be randomly assigned to receive either taVNS plus tirzepatide 5 mg or sham stimulation plus tirzepatide 5 mg for 12 weeks. The primary objective is to compare the percent change in body weight from baseline to week 12 between the two groups.
Individuals with obesity, or overweight accompanied by at least one weight-related comorbidity (e.g., hypertension or fatty liver disease), who have been receiving tirzepatide therapy for at least 12 weeks and have achieved ≤10% weight loss during treatment;
Willingness to provide written informed consent.
Presence of diseases that may substantially affect body weight homeostasis, including Cushing's syndrome, uncontrolled thyroid disease (thyroid-stimulating hormone >6.0 mIU/L or <0.4 mIU/L), malignancy, or similar conditions;
Use within the past 3 months of medications, other than incretin receptor agonists, that may significantly affect body weight, including glucocorticoids and antipsychotic agents;
Skin infection or damage involving the auricular area;
Women planning pregnancy in the near future;
Parallel
transcutaneous auricular vagus nerve stimulation
DeviceParticipants will receive active transcutaneous auricular vagus nerve stimulation plus tirzepatide 5 mg for 12 weeks. Active stimulation will be delivered to the bilateral cymba conchae, an auricular region innervated by the auricular branch of the vagus nerve. Stimulation will use an intermittent waveform of 15 seconds on and 5 seconds off at 20 Hz, with a pulse width of 0.2 ms. Stimulation intensity will be titrated from 0 mA to a level that produces mild tingling without obvious discomfort, usually 1.0-2.5 mA. Stimulation will be administered twice daily for 30 minutes per session, 5 days per week, for 12 weeks. Tirzepatide will be administered as a subcutaneous injection once weekly.
Sham
DeviceParticipants will receive sham stimulation in addition to tirzepatide 5 mg for 12 weeks. Sham stimulation will be applied to the bilateral tail of the helix, an auricular site without vagus nerve distribution, whereas active taVNS targets the cymba conchae, which is innervated by the auricular branch of the vagus nerve. The sham group will use the same waveform parameters, stimulation intensity titration, and treatment schedule as the active group, namely twice daily for 30 minutes per session, 5 days per week, for 12 weeks. Tirzepatide will be administered as a subcutaneous injection once weekly.
Percent Change in Body Weight From Baseline
Percent change in body weight from baseline to week 12 will be compared between the taVNS plus tirzepatide group and the sham stimulation plus tirzepatide group to evaluate the adjunctive effect of taVNS on weight reduction.
Change in Waist Circumference
Change in waist circumference from baseline to Week 4, Week 8, and Week 12 will be assessed using standardized anthropometric measurement.
Change in Body Composition and Fat Distribution
Changes in body composition and fat distribution will be assessed by body fat percentage using anthropometric measurements and body composition analysis.
Change in blood glucose
Change in fasting blood glucose from baseline to Week 12 will be assessed using laboratory testing.
Change in Hip Circumference
Change in hip circumference from baseline to Week 4, Week 8, and Week 12 will be assessed using standardized anthropometric measurement.
Change in Brain Biotype
Changes in brain biotype after 12 weeks of intervention will be explored using brain MRI-based analyses. Brain biotype will be assessed at baseline and Week 12 using brain MRI-based analyses. Brain biotype will be defined as an MRI-derived classification based on pre-specified brain imaging features, such as resting-state functional connectivity patterns. Participants will be assigned to a brain biotype category according to the pre-specified MRI analysis algorithm.
Click on the lead sponsor to view all of their trials.
