Brown Adipose Tissue (BAT) PhysiologyACROBATNCT06978777
Effect of Caffeine on Cold-stimulated Brown Adipose Tissue Activity
A study testing Caffeine (200 mg) in people with Brown Adipose Tissue (BAT) Physiology and Cold Exposure, run by University Hospital, Basel, Switzerland at 1 site in Switzerland.
Trial summary
The purpose of the study is to asses brown adipose tissue activity after a cold mild stimulus, preceded by 200mg caffeine or placebo administration. Read more about this study
- Who is it for?
- Ages 18 to 40 yearsHealthy volunteers can take part
- Conditions the study is for
- Brown Adipose Tissue (BAT) Physiology, Cold Exposure
- What is being tested?
- Caffeine (200 mg)
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 12 participants
- Where
- 1 siteSwitzerland
- Study dates
- 21 Jan 2026to 28 May 2026
- Phase
- Interventional
- 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 18 to 40 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- BMI 18.5 to 25 kg/m2
- Able to give informed consent as documented by signature
- Moderate caffeine consumption (1 to 3 cups of coffee per day)
- Increase of EE in response to mild cold of ≥ 5% of REE
Who cannot join
- Known hypersensitivity or allergy to caffeine
- Concomitant medication other than prescription free analgesics (paracetamol and NSAID) and oral contraceptives
- Other clinically significant concomitant disease states (e.g., renal failure, hepatic dysfunction, cardiovascular disease, cardiac arrhythmia, hypertension, diabetes mellitus, hyper- or hypothyroidism)
- History of depressive disorder or anxiety disorder
- Smoker / habitual tobacco use
- Habitual excessive alcohol use
Show all 16Show fewer
- Regular consumption of caffeine containing energy drinks
- Weight change of >5% within 3 months prior to inclusion
- Systolic blood pressure >140 mmHg and/or diastolic blood pressure > 95 mmHg.
- Resting heart rate >90 bpm
- Hypersensitivity to cold (e.g. Raynaud syndrome)
- Known or suspected non-compliance, drug or alcohol abuse
- Inability to follow the procedures of the study, e.g. due to language problems, psychological disorders, dementia, etc. of the participant.
- Enrolment of the investigator, his/her family members, employees, and other dependent persons
- Enrolment into another study using ionizing radiation within the previous 12 months.
- Pregnancy or lactation
Trial locations and contacts
1 site in 1 country.
Switzerland1 site
University Hospital Basel, Department of Endocrinology
Basel, 4031
About this study
The purpose of the study is to asses brown adipose tissue activity after a cold mild stimulus, preceded by 200mg caffeine or placebo administration.
Read the detailed description
Brown adipose tissue (BAT) activation is typically through beta3-adrenoceptors (beta3-AR), but beta3-alone are less efficacious than cold in activating human BAT. Recent research suggests that adenosine, released during cold exposure, plays a key role in BAT thermogenesis. This study aims to investigate the role of the adenosine A2A receptor (A2AR) in BAT activation through a randomized trial with mild cold exposure and caffeine, a potent A2AR antagonist, to explore new therapeutic strategies for metabolic diseases.
This is a randomized, double-blind, placebo-controlled cross-over trial involving healthy volunteers. The study includes a screening visit and two main study visits (A and B), which will occur in random order.
During the two study visits, resting energy expenditure will be assessed by indirect calorimetry under warm conditions and following mild cold exposure, after administration of either caffeine or placebo. For cold exposure, participants will wear cooling sleeves around the waist, which gradually lower the surface body temperature to 10°C or to the lowest tolerable temperature without inducing shivering.
Additionally, BAT activity will be assessed using 18F-FDG PET/CT, performed 30 minutes after the injection of 75 MBq of 18F-FDG.
- Being tested
- Caffeine (200 mg), Placebo
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Caffeine (200 mg)Drug
single dose of 200mg caffeine orally in study visit A
PlaceboDrug
single dose of 1 tablet Placebo in study visit B
| Study group | Role | What they receive |
|---|---|---|
| Caffeine | Active comparator | Participants will be administered a single dose of 200mg caffeine orally in study visite A, before exposing to a mild cold stimulus. Resting energy expenditure will be measured before an after administration of caffeine and cold exposure. Receives: Drug: Caffeine (200 mg) |
| Placebo | Placebo comparator | Participants will be administered a single dose of placebo tablet orally in study visite B, before exposing to a mild cold stimulus. Resting energy expenditure will be measured before an after administration of placebo and cold exposure. Receives: Drug: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
BAT SUVmean
Description: 18F-FDG uptake into the supra-clavicular brown adipose tissue as determined by 18F-FDG PET-CT after the respective study intervention
Measured: 30 minutes after end of intervention in study visit A and B.
Secondary outcomes (8)
BAT SUVmax
maximum SUV in supraclavicular adipose tissue (according to BARCIST 1.0) as determined by 18F-FDG PET-CT after the respective study intervention
Measured: 30 minutes after intervention in study visit A and B.
BAT Volume
volume of supraclavicular adipose tissue (according to BARCIST 1.0) as determined by 18F-FDG PET-CT after the respective study intervention.
Measured: 30 minutes after intervention in study visit A and B.
Cold induced thermogenesis (CIT)
rise in energy expenditure above baseline occurring during mild cold exposure in the respective study intervention.
Measured: immediately after the intervention (caffeine or placebo)
Resting energy expenditure (REE)
REE during warm conditions and at the end of cold exposure.
Measured: immediately after the intervention (caffeine or placebo)
Respiratory exchange ratio (RER):
Ratio between carbon dioxide production and oxygen consumption (VCO2/VO2) during the enregy expenditure (EE) measurements.
Measured: immediately after the intervention (caffeine or placebo)
Skin temperature
Changes in skin temperature after mild cold stimulus. It will be measured during the hole study visits during warm condition and after cold stimulation, using wireless temperature sensors (iButton Thermochron) attached to the skin at 11 pre-defined locations
Measured: immediately after the intervention (caffeine or placebo)
Metabolom and Lipidome profile
Plasma metabolome and lipidome profiles.
Measured: immediately after the intervention (caffeine or placebo)
Caffeine and its metabolites
Plasma caffeine and its metabolites.
Measured: immediately after the intervention (caffeine or placebo)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted18 May 2025
- Study start21 Jan 2026
- Primary completion28 May 2026
- Study completion28 May 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Brown Adipose Tissue (BAT) PhysiologyStudies of the same condition, open and under way.
- More trials run by University Hospital, Basel, SwitzerlandThe 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 N/A
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- Randomized, double-blind, placebo-controlled cross-over trial in healthy volunteers with random sequence of the two study interventions.
- Masking
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 12 participants (actual)
Sponsor and investigators
- Lead sponsor
- University Hospital, Basel, Switzerland
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Matthias Betz, Prof., Principal investigator, University Hospital, Basel, Switzerland
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06978777
- Sponsor's protocol ID
- ACROBAT_V1_1
- Acronym
- ACROBAT
- Status last verified
- Jul 2026
- First submitted
- 2 May 2025
- Last updated
- 31 Jul 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 31 Jul 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effect of Caffeine on Cold-stimulated Brown Adipose Tissue Activity
- ClinicalTrials.gov ID
- NCT06978777
- Acronym / sponsor ID
- ACROBAT / ACROBAT_V1_1
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 12 participants (actual)
- Lead sponsor
- University Hospital, Basel, SwitzerlandUniversity, hospital or other
- Study start
- 21 Jan 2026 (actual)
- Primary completion
- 28 May 2026 (actual)
- Study completion
- 28 May 2026 (actual)
- First posted
- 18 May 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.
The purpose of the study is to asses brown adipose tissue activity after a cold mild stimulus, preceded by 200mg caffeine or placebo administration.
Detailed description
Brown adipose tissue (BAT) activation is typically through beta3-adrenoceptors (beta3-AR), but beta3-alone are less efficacious than cold in activating human BAT. Recent research suggests that adenosine, released during cold exposure, plays a key role in BAT thermogenesis. This study aims to investigate the role of the adenosine A2A receptor (A2AR) in BAT activation through a randomized trial with mild cold exposure and caffeine, a potent A2AR antagonist, to explore new therapeutic strategies for metabolic diseases.
This is a randomized, double-blind, placebo-controlled cross-over trial involving healthy volunteers. The study includes a screening visit and two main study visits (A and B), which will occur in random order.
During the two study visits, resting energy expenditure will be assessed by indirect calorimetry under warm conditions and following mild cold exposure, after administration of either caffeine or placebo. For cold exposure, participants will wear cooling sleeves around the waist, which gradually lower the surface body temperature to 10°C or to the lowest tolerable temperature without inducing shivering.
Additionally, BAT activity will be assessed using 18F-FDG PET/CT, performed 30 minutes after the injection of 75 MBq of 18F-FDG.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Triple blind (participant, investigator, outcomes assessor)
- Number of arms
- 2
- Model description
- Randomized, double-blind, placebo-controlled cross-over trial in healthy volunteers with random sequence of the two study interventions.
| Arm | Type | Receives |
|---|---|---|
| Caffeine | Active comparator | Drug: Caffeine (200 mg)Participants will be administered a single dose of 200mg caffeine orally in study visite A, before exposing to a mild cold stimulus. Resting energy expenditure will be measured before an after administration of caffeine and cold exposure. |
| Placebo | Placebo comparator | Drug: PlaceboParticipants will be administered a single dose of placebo tablet orally in study visite B, before exposing to a mild cold stimulus. Resting energy expenditure will be measured before an after administration of placebo and cold exposure. |
Who may qualify
- Ages
- 18 to 40 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (4 listed)
- BMI 18.5 to 25 kg/m2
- Able to give informed consent as documented by signature
- Moderate caffeine consumption (1 to 3 cups of coffee per day)
- Increase of EE in response to mild cold of ≥ 5% of REE
Key exclusion criteria (16 listed)
- Known hypersensitivity or allergy to caffeine
- Concomitant medication other than prescription free analgesics (paracetamol and NSAID) and oral contraceptives
- Other clinically significant concomitant disease states (e.g., renal failure, hepatic dysfunction, cardiovascular disease, cardiac arrhythmia, hypertension, diabetes mellitus, hyper- or hypothyroidism)
- History of depressive disorder or anxiety disorder
- Smoker / habitual tobacco use
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 |
|---|---|---|
| Caffeine (200 mg)single dose of 200mg caffeine orally in study visit A | Drug | Caffeine |
| Placebosingle dose of 1 tablet Placebo in study visit B | Drug | Placebo |
Primary outcome
BAT SUVmean
Time frame: 30 minutes after end of intervention in study visit A and B.
Description: 18F-FDG uptake into the supra-clavicular brown adipose tissue as determined by 18F-FDG PET-CT after the respective study intervention
8 secondary outcomes
BAT SUVmax
Time frame: 30 minutes after intervention in study visit A and B.
BAT Volume
Time frame: 30 minutes after intervention in study visit A and B.
Cold induced thermogenesis (CIT)
Time frame: immediately after the intervention (caffeine or placebo)
Resting energy expenditure (REE)
Time frame: immediately after the intervention (caffeine or placebo)
Respiratory exchange ratio (RER):
Time frame: immediately after the intervention (caffeine or placebo)
Skin temperature
Time frame: immediately after the intervention (caffeine or placebo)
Metabolom and Lipidome profile
Time frame: immediately after the intervention (caffeine or placebo)
Caffeine and its metabolites
Time frame: immediately after the intervention (caffeine or placebo)
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 31 Jul 2026.
- Individual participant dataSharing planned: No
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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.
Matthias Betz, Prof. principal investigator
University Hospital, Basel, Switzerland
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Caffeine (200 mg) in people with Brown Adipose Tissue (BAT) Physiology and Cold Exposure, run by University Hospital, Basel, Switzerland at 1 site in Switzerland.
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 4 inclusion and 16 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 31 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 Switzerland. 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.
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?
BAT SUVmean (time frame: 30 minutes after end of intervention in study visit A and B.). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
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 31 Jul 2026.