ObesityPhase 2TABFATNCT06893211
Effect of Tirzepatide on Brown Adipose Tissue in Obesity
A Phase 2 study testing Tirzepatide in people with Obesity, run by University Medical Centre Ljubljana at 1 site in Slovenia.
Trial summary
This study is testing whether a new anti-obesity medicine called tirzepatide can increase the activity of special fat cells in the body that help burn energy. These fat cells are known as brown and beige fat. The study includes women with obesity and will last 24 weeks. Read more about this study
- Who is it for?
- Ages 20 to 50 years, women only
- Conditions the study is for
- Obesity
- What is being tested?
- Tirzepatide
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 34 participants
- Where
- 1 siteSlovenia
- Study dates
- 18 Mar 2025to 20 Dec 2025
- Phase
- Phase 2
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 20 to 50 years
- Women only
- No healthy volunteers
- Adult
Who may be able to join
- Female sex
- Age between 18 and 50 years
- BMI between 30 kg/m² and 40 kg/m² at pre-screening
- Prior comprehensive non-pharmacological and non-surgical management of obesity, including a history of at least 12 months of intensive lifestyle intervention with a maximum weight reduction of less than 5%
- Stable body weight within the three months preceding study enrollment (defined as weight fluctuations within 5%)
- No prior pharmacological or surgical interventions for obesity
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- Euthyroid state
- Eumenorrhea or Oligomenorrhea
- Ability to comprehend the study objectives and procedures
- Willingness to provide informed consent and to comply with the study protocol, including the use of highly effective contraception during the study period, with signed consent and agreement provided in duplicate
- Commitment to use highly reliable contraception and absence of plans for pregnancy within the 8 months following enrollment
Who cannot join
- Pregnancy or lactation
- Postmenopausal
- Amenorea
- Type 2 diabetes
- Reliance on natural contraception methods
- Non-compliance with previous therapeutic regimens
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- Personal history of malignancy
- Personal or family history of medullary thyroid carcinoma
- Personal history of pancreatitis
- Personal history of cholelithiasis
- Personal history of major depressive episodes or suicidal ideation
- Personal history of acute coronary events or hemodynamically significant coronary artery disease
- Psychiatric disorders
- Current treatment with sympathomimetics or sympatholytics
- Excessive alcohol consumption
Trial locations and contacts
1 site in 1 country.
Slovenia1 site
Department of Endocrinology, Diabetes and Metabolic Diseases, University Medical Centre Ljubljana
Ljubljana, 1000
About this study
Official title: Effect of Tirzepatide-Induced Weight Loss on Adipose Tissue in Obesity
This study is testing whether a new anti-obesity medicine called tirzepatide can increase the activity of special fat cells in the body that help burn energy. These fat cells are known as brown and beige fat. The study includes women with obesity and will last 24 weeks.
Participants will receive either tirzepatide or a placebo (a look-alike injection with no active drug). Researchers will measure the amount and activity of brown fat using medical imaging (PET/CT, MRI, and thermal camera), and examine fat tissue samples to look for changes in gene activity and structure that show beige fat activation.
The study will also evaluate how these fat changes affect body weight, energy use, hormone levels, blood sugar, and other health markers. The goal is to learn whether tirzepatide helps improve metabolism by increasing energy-burning fat in addition to reducing appetite.
- Conditions
- Obesity
- Being tested
- Tirzepatide, Placebo
- Keywords
- obesity, tirzepatide, brown adipose tissue, beige adipose tissue, adipose tissue browning, energy expenditure
- Medical subject headings
- Obesity
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
TirzepatideDrug
Tirzepatide is a dual glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptor agonist. It will be administered via subcutaneous injection once weekly in a dose-titration scheme: starting at 2.5 mg, and increased every 4 weeks by 2.5 mg up to a maximum of 15 mg, based on tolerability. The medication will be supplied in prefilled pens identical in appearance to placebo pens.
PlaceboDrug
Placebo will be administered via subcutaneous injection once weekly using pens that are visually indistinguishable from those used for tirzepatide. Dose escalation will follow the same schedule (2.5 mg-equivalent increments every 4 weeks) to preserve blinding integrity.
| Study group | Role | What they receive |
|---|---|---|
| Tirzepatide | Experimental | Not described Receives: Drug: Tirzepatide |
| Placebo | Placebo comparator | Not described Receives: Drug: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in Brown Adipose Tissue Activity and Volume
Assessed using 18F-FDG-PET/CT, magnetic resonance imaging (MRI), and infrared thermography. Outcome measured as change in mean standardized uptake value, supraclavicular skin temperature, and BAT volume in predefined anatomical regions (supraclavicular and cervical areas) between baseline and after 24 weeks of treatment.
Measured: Baseline to Week 24
Change in Molecular Markers of Browning in Subcutaneous White Adipose Tissue
Measured as changes in the expression levels of uncoupling protein 1 (UCP1) and other browning-associated genes (via RT-PCR and RNA sequencing) in subcutaneous white adipose tissue (WAT) biopsies. Additionally, assessed through histomorphometric analysis of adipocyte phenotype, including the proportion of multilocular (plurivacuolar) adipocytes, immune cell infiltration, and microvascular density, to characterize tissue remodeling indicative of beige adipocyte induction.
Measured: Baseline to Week 24
Secondary outcomes (4)
Correlation Between Different BAT Assessment Methods
Comparative analysis between 18F-FDG-PET/CT, MRI fat fraction, and infrared thermography for assessing BAT activity and volume.
Measured: Baseline and Week 24
Change in Resting Energy Expenditure
Measured by indirect calorimetry using a portable metabolic analyzer. Outcome reported as absolute change in REE (kcal/day).
Measured: Baseline to Week 24
Association Between Changes in Resting Energy Expenditure, Metabolic Health Markers, and Thermogenic Adipose Tissue
Assessed by evaluating correlations between changes in resting energy expenditure (REE, measured by indirect calorimetry), metabolic health parameters (including glucose metabolism, insulin sensitivity indices, lipid profile, and hormonal markers), body composition changes, and alterations in thermogenic adipose tissue activity and volume (as measured by 18F-FDG-PET/CT, MRI, and thermography). This outcome aims to determine the interrelationship between metabolic adaptations and thermogenic fat activation following tirzepatide treatment.
Measured: Baseline to Week 24
Association Between Resting Energy Expenditure, Metabolic Health Markers, and Thermogenic Adipose Tissue
Assessed by evaluating correlations between anthropometric data, resting energy expenditure (REE, measured by indirect calorimetry), metabolic health parameters (including glucose metabolism, insulin sensitivity indices, lipid profile, and hormonal markers), body composition, and thermogenic adipose tissue activity and volume (as measured by 18F-FDG-PET/CT, MRI, and thermography). This outcome aims to determine variables that correlate with pre-treatment thermogenic adipose tissue quantity and activity.
Measured: Baseline
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted25 Mar 2025
- Study start18 Mar 2025
- Primary completion29 Nov 2025
- Study completion20 Dec 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for ObesityStudies of the same condition, open and under way.
- More trials run by University Medical Centre LjubljanaThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind
- Who is masked
- Participant
- Enrolment
- 34 participants (actual)
Sponsor and investigators
- Lead sponsor
- University Medical Centre Ljubljana
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06893211
- Sponsor's protocol ID
- 0120-56/2024-2711-7
- Acronym
- TABFAT
- Status last verified
- May 2025
- First submitted
- 18 Mar 2025
- Last updated
- 7 Jul 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: De-identified individual participant data (IPD) to be shared will include demographic data, basic clinical measurements, body composition assessment, laboratory results, imaging data, resting energy expenditure measurements, molecular data and histological features from subcutaneous adipose tissue biopsies. All shared data will be fully de-identified, and no directly identifiable personal information will be included.
Publications
Herman R, Jensterle M, Horvat S, Lezaic L, Snoj Z, Pusnik I, Goricar K, Cor A, Pusnik L, Mlacnik V, Hanzelic L, Janez A. Effect of tirzepatide-induced weight loss on adipose tissue in obesity: rationale and design of the randomized placebo-controlled Tirzepatide Brown and Beige Adipose Tissue Activation (TABFAT) trial. Trials. 2025 Aug 22;26(1):300. doi: 10.1186/s13063-025-09045-9.
PubMed 40847412
Study at a glance
From the registry record, last updated by the sponsor on 7 Jul 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effect of Tirzepatide-Induced Weight Loss on Adipose Tissue in Obesity
- ClinicalTrials.gov ID
- NCT06893211
- Acronym / sponsor ID
- TABFAT / 0120-56/2024-2711-7
- Conditions
- Obesity
- Keywords
- obesity, tirzepatide, brown adipose tissue, beige adipose tissue, adipose tissue browning, energy expenditure
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 34 participants (actual)
- Lead sponsor
- University Medical Centre LjubljanaUniversity, hospital or other
- Study start
- 18 Mar 2025 (actual)
- Primary completion
- 29 Nov 2025 (actual)
- Study completion
- 20 Dec 2025 (actual)
- First posted
- 25 Mar 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study is testing whether a new anti-obesity medicine called tirzepatide can increase the activity of special fat cells in the body that help burn energy. These fat cells are known as brown and beige fat. The study includes women with obesity and will last 24 weeks.
Participants will receive either tirzepatide or a placebo (a look-alike injection with no active drug). Researchers will measure the amount and activity of brown fat using medical imaging (PET/CT, MRI, and thermal camera), and examine fat tissue samples to look for changes in gene activity and structure that show beige fat activation.
The study will also evaluate how these fat changes affect body weight, energy use, hormone levels, blood sugar, and other health markers. The goal is to learn whether tirzepatide helps improve metabolism by increasing energy-burning fat in addition to reducing appetite.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (participant)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Tirzepatide | Experimental | Drug: Tirzepatide |
| Placebo | Placebo comparator | Drug: Placebo |
Who may qualify
- Ages
- 20 to 50 years
- Sex
- Female only
- Healthy volunteers
- Not accepted
- Age groups
- Adult
Key inclusion criteria (11 listed)
- Female sex
- Age between 18 and 50 years
- BMI between 30 kg/m² and 40 kg/m² at pre-screening
- Prior comprehensive non-pharmacological and non-surgical management of obesity, including a history of at least 12 months of intensive lifestyle intervention with a maximum weight reduction of less than 5%
- Stable body weight within the three months preceding study enrollment (defined as weight fluctuations within 5%)
Key exclusion criteria (15 listed)
- Pregnancy or lactation
- Postmenopausal
- Amenorea
- Type 2 diabetes
- Reliance on natural contraception methods
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| TirzepatideTirzepatide is a dual glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptor agonist. It will be administered via subcutaneous injection once weekly in a dose-titration scheme: starting at 2.5 mg, and increased every 4 weeks by 2.5 mg up to a maximum of 15 mg, based on tolerability. The medication will be supplied in prefilled pens identical in appearance to placebo pens. | Drug | Tirzepatide |
| PlaceboPlacebo will be administered via subcutaneous injection once weekly using pens that are visually indistinguishable from those used for tirzepatide. Dose escalation will follow the same schedule (2.5 mg-equivalent increments every 4 weeks) to preserve blinding integrity. | Drug | Placebo |
Primary outcome
Change in Brown Adipose Tissue Activity and Volume
Time frame: Baseline to Week 24
Assessed using 18F-FDG-PET/CT, magnetic resonance imaging (MRI), and infrared thermography. Outcome measured as change in mean standardized uptake value, supraclavicular skin temperature, and BAT volume in predefined anatomical regions (supraclavicular and cervical areas) between baseline and after 24 weeks of treatment.
Change in Molecular Markers of Browning in Subcutaneous White Adipose Tissue
Time frame: Baseline to Week 24
Measured as changes in the expression levels of uncoupling protein 1 (UCP1) and other browning-associated genes (via RT-PCR and RNA sequencing) in subcutaneous white adipose tissue (WAT) biopsies. Additionally, assessed through histomorphometric analysis of adipocyte phenotype, including the proportion of multilocular (plurivacuolar) adipocytes, immune cell infiltration, and microvascular density, to characterize tissue remodeling indicative of beige adipocyte induction.
4 secondary outcomes
Correlation Between Different BAT Assessment Methods
Time frame: Baseline and Week 24
Change in Resting Energy Expenditure
Time frame: Baseline to Week 24
Association Between Changes in Resting Energy Expenditure, Metabolic Health Markers, and Thermogenic Adipose Tissue
Time frame: Baseline to Week 24
Association Between Resting Energy Expenditure, Metabolic Health Markers, and Thermogenic Adipose Tissue
Time frame: Baseline
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 7 Jul 2026.
- Derived from this study: PubMed 40847412Herman R, Jensterle M, Horvat S, Lezaic L, Snoj Z, Pusnik I, Goricar K, Cor A, Pusnik L, Mlacnik V, Hanzelic L, Janez A. Effect of tirzepatide-induced weight loss on adipose tissue in obesity: rationale and design of the randomized placebo-controlled Tirzepatide Brown and Beige Adipose Tissue Activation (TABFAT) trial. Trials. 2025 Aug 22;26(1):300. doi: 10.1186/s13063-025-09045-9.
- Individual participant dataSharing planned: Yes. De-identified individual participant data (IPD) to be shared will include demographic data, basic clinical measurements, body composition assessment, laboratory results, imaging data, resting energy expenditure measurements, molecular data and histological features from subcutaneous adipose tissue biopsies. All shared data will be fully de-identified, and no directly identifiable personal information will be included.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing Tirzepatide in people with Obesity, run by University Medical Centre Ljubljana at 1 site in Slovenia.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 11 inclusion and 15 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 7 Jul 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Slovenia. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in Brown Adipose Tissue Activity and Volume (time frame: Baseline to Week 24). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT06893211, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 7 Jul 2026.