An interventional study of Semaglutide (Wegovy®) and ¹⁸FDG-PET/CT with cold stimulation in Obesity, Metabolic Syndrome and Brown Adipose Tissue, sponsored by Hallym University. Not yet recruiting at 2 sites in South Korea. Open to participants aged 20 Years to 70 Years. Per ClinicalTrials.gov, last updated 2026-07-22.
Sponsored by Hallym University · Not applicable, Interventional, and Basic science
This study investigates whether the activity of brown adipose tissue (BAT) - a special type of fat that burns energy as heat - can predict how well individuals with obesity respond to semaglutide (Wegovy), a once-weekly injectable weight loss medication. Participants who are starting semaglutide treatment will undergo ¹⁸FDG-PET/CT imaging before and after 24 weeks of treatment. Prior to each PET/CT scan, participants will wear a water-circulating cooling vest to activate BAT. By measuring BAT activity at baseline and comparing it with the degree of weight loss and metabolic improvement at 24 weeks, the investigators aim to identify BAT as a predictive biomarker for personalized obesity treatment.
Despite the remarkable efficacy of semaglutide (GLP-1 receptor agonist) in treating obesity, considerable individual variation in treatment response remains unexplained. Brown adipose tissue (BAT) is a metabolically active thermogenic organ that has been implicated in energy expenditure, insulin sensitivity, and cardiometabolic health. We hypothesize that baseline BAT activity, as measured by ¹⁸FDG-PET/CT following individualized cold stimulation, is a mechanistic determinant of semaglutide treatment response in adults with obesity without diabetes.
This multicenter prospective cohort study will enroll 80 adults (40 per site: Hallym University Dongtan Sacred Heart Hospital and Seoul National University Bundang Hospital) with BMI ≥27 kg/m² plus obesity-related comorbidity, or BMI ≥30 kg/m², who are initiating semaglutide therapy. ¹⁸FDG-PET/CT with standardized cold stimulation (water-circulating cooling vest, starting at 16°C, individualized to prevent shivering) will be performed at baseline (V1) and 24 weeks (V7). BAT activity (SUVmax, SUVmean, BAT volume, total metabolic activity) will be quantified per BARCIST 1.0 criteria. Liver fat fraction (MRI-PDFF) and liver stiffness (MR elastography) will be assessed as secondary endpoints. Correlations between baseline BAT parameters and treatment outcomes (% body weight loss, metabolic biomarker changes) will be analyzed.
11,522 studies on the registry are indexed under Obesity; 2,033 are open to participants now.
This study's planned enrollment of 80 is above the median of 67 across 9,006 interventional studies indexed under Obesity.
Browse Obesity studies →Hallym University is the lead sponsor of 2 studies on the registry; 2 are open to participants now.
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Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
≥ 27 kg/m² with at least one weight-related comorbidity:
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.
Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.
The top of the normal range for a blood test, as set by the laboratory that runs it. Each lab prints its own range next to your result.
“≤ 2.5 × ULN” means the result can be up to two and a half times that top value.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
GFR (glomerular filtration rate) is how much blood the kidneys filter each minute. It is usually estimated from a blood test — eGFR, by formulas such as CKD-EPI or MDRD — and some studies ask for it to be measured directly instead. Usually given in mL/min/1.73 m².
Check the method, the units and the minimum the study states. A value of 90 or above is in the normal-or-high range, but kidney damage can show in other tests too.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ALT and AST (liver enzymes)
Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.
Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ULN (upper limit of normal)
The top of the normal range for a blood test, as set by the laboratory that runs it. Each lab prints its own range next to your result.
“≤ 2.5 × ULN” means the result can be up to two and a half times that top value.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Cancer (malignancy)
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
GFR and eGFR (kidney filtering)
GFR (glomerular filtration rate) is how much blood the kidneys filter each minute. It is usually estimated from a blood test — eGFR, by formulas such as CKD-EPI or MDRD — and some studies ask for it to be measured directly instead. Usually given in mL/min/1.73 m².
Check the method, the units and the minimum the study states. A value of 90 or above is in the normal-or-high range, but kidney damage can show in other tests too.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Adults with obesity initiating semaglutide (0.25 mg → 2.4 mg over 20 weeks, maintained for 4 weeks; total 24 weeks). At baseline and 24 weeks, ¹⁸FDG-PET/CT with individualized cold stimulation (water-circulating cooling vest at 16°C, 60 minutes) and liver MRI (PDFF + MRE) are performed.
Drug: Semaglutide (Wegovy®) · Procedure: ¹⁸FDG-PET/CT with cold stimulation · Procedure: Liver MRI (PDFF + MRE)
Once-weekly subcutaneous injection, titrated from 0.25 mg to 2.4 mg over 20 weeks per standard protocol. Standard of care treatment for obesity.
Whole-body ¹⁸FDG-PET/CT (5.18 MBq/kg, max 370 MBq) after 60-minute individualized cold stimulation using a water-circulating cooling vest (Polar Products Arctic Chiller, starting 16°C). Performed at baseline (V1) and 24 weeks (V7). BAT activity quantified per BARCIST 1.0.
Hepatic proton density fat fraction (MRI-PDFF) and liver stiffness by MR elastography (MRE) using Siemens MAGNETOM Vida 3T. Performed at baseline (V1) and 24 weeks (V7).
Correlation between baseline BAT metabolic activity (SUVmean and BAT volume on ¹⁸FDG-PET/CT) and percentage body weight loss at 24 weeks of semaglutide treatment
: Pearson (or Spearman) correlation coefficient between baseline BAT parameters (SUVmean, BAT volume, total metabolic activity per BARCIST 1.0) and % body weight loss after 24 weeks of semaglutide therapy (0.25 mg escalated to 2.4 mg).
Time frame: Baseline to 24 weeks
Change in waist circumference
Time frame: Baseline to 24 weeks
Change in body weight (kg)
Time frame: Baseline to 24 weeks
Change in Body Mass Index (BMI)
Time frame: Baseline to 24 weeks
Change in HbA1c (%)
Time frame: Baseline to 24 weeks
Change in fasting glucose (mg/dL)
Time frame: Baseline to 24 weeks
Change in HOMA-IR
Time frame: Baseline to 24 weeks
Change in fasting lipids (LDL-C, HDL-C, TG, TC)
Time frame: Baseline to 24 weeks
Change in body composition by BIA (fat mass, lean mass, skeletal muscle mass)
Time frame: Baseline to 24 weeks
Change in liver fat fraction (MRI-PDFF, %)
Time frame: Baseline to 24 weeks
Change in liver stiffness by MRE (kPa)
Time frame: Baseline to 24 weeks
Change in adipokines (adiponectin, leptin, NEFA)
Time frame: Baseline to 24 weeks
Change in hsCRP
Time frame: Baseline to 24 weeks
BAT-positive rate based on SUVmax at baseline
The percentage of participants determined as brown adipose tissue (BAT)-positive, defined by a maximum standardized uptake value (SUVmax) of 1.5 or higher ($\\ge 1.5$) at baseline.
Time frame: Baseline
Change in Quality of life using the Impact of Weight on Quality of Life-Lite Clinical Trials (IWQOL-Lite-CT) total score
The Impact of Weight on Quality of Life-Lite Clinical Trials (IWQOL-Lite-CT) is a self-report questionnaire used to assess the quality of life in individuals with obesity. The total score ranges from a minimum of 0 to a maximum of 100, where higher scores indicate a better outcome (better quality of life).
Time frame: Baseline to 24 weeks
Change in Quality of Life using the Short Form-36 Health Survey Version 2 (SF-36v2) domain scores
The Short Form-36 Health Survey Version 2 (SF-36v2) is a 36-item questionnaire measuring health-related quality of life across 8 domains: Physical Functioning, Role-Physical, Bodily Pain, General Health, Vitality, Social Functioning, Role-Emotional, and Mental Health. Each domain score ranges from a minimum of 0 to a maximum of 100, where higher scores indicate a better outcome (better health status or higher quality of life).
Time frame: Baseline to 24 weeks
Change in BAT activity (SUVmax, SUVmean, BAT volume, TMA) from baseline to 24 weeks
Time frame: Baseline to 24 weeks
BAT-positive rate based on CT Hounsfield Units (HU) at baseline
The percentage of participants determined as brown adipose tissue (BAT)-positive, defined by Computed Tomography Hounsfield Units (CT HU) within the range of $-250$ to $-50$ at baseline.
Time frame: Baseline
Plan to share: No — Individual participant data will not be shared publicly. De-identified aggregate results will be published in peer-reviewed journals
No publications or documents are linked to this record.
Start is estimated for Jun 2026; primary completion for Feb 2028, 20 months later.
Of 3,680 non-industry interventional studies with no phase under Obesity, half reached primary completion within 23 months of starting (the median), counting those still running; a quarter within 10 and three quarters within 43. This study's planned 20 months is below that.
Counting every sponsor, half of 3,843 studies reached it within 22 months; a quarter within 10 and three quarters within 42.
How these figures are worked out, and which studies are left out of them.
This study is not yet recruiting, as verified in Jul 2026. You cannot join it, but the record below documents what was studied.
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Hallym University