HypertensionNCT06820944
Theobromine From Cocoa and Cardiovascular Risk Factors
A study testing dark chocolate and white chocolate in people with Hypertension, run by Chiang Mai University at 1 site in Thailand.
Trial summary
The goal of this clinical trial is to examine whether consumption of dark chocolate affects blood pressure and a cardiovascular risk factor called trimethylamine N-oxide in Thai male participants with hypertension. Read more about this study
- Who is it for?
- Ages 35 to 70 years, men only
- Conditions the study is for
- Hypertension
- What is being tested?
- dark chocolate and white chocolate
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 53 participants
- Where
- 1 siteThailand
- Study dates
- 15 Feb 2025to 30 Apr 2025
- 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 35 to 70 years
- Men only
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Male
- Age between 35 to 70 years
- BMI less than 30 kg/m^2
- Systolic blood pressure between 130 to 159 mmHg or Diastolic blood pressure between 85 to 99 mmHg.
- Do not smoke.
Who cannot join
- Cannot drink beverages and consume foods that have caffeine.
- Take medicine to lower cholesterol and triglyceride levels, treat high blood pressure, or diabetes.
- Have liver and kidney inflammation.
- Use antibiotics within 1 month of study.
- Use choline or probiotic supplements regularly within 1 month of study.
- Consume more than 30 alcoholic drinks per week.
- Have chronic diseases.
Trial locations and contacts
1 site in 1 country.
Thailand1 site
Research Institute for Health Sciences, Chiang Mai University
Mueang, Chiang Mai, 50200
About this study
Official title: Theobromine Consumption From Cocoa and Cardiovascular Risk Factors in Humans: Evidence for Health Claims
The goal of this clinical trial is to examine whether consumption of dark chocolate affects blood pressure and a cardiovascular risk factor called trimethylamine N-oxide in Thai male participants with hypertension. The main questions it aims to answer are:
Can consumption of dark chocolate lower blood pressure? Can consumption of dark chocolate lower blood trimethylamine N-oxide?
Read more
Researchers will compare dark chocolate to white chocolate to see if the effects are due to theobromine (a key bioactive compound in dark chocolate).
Participants will consume either 100 g 72% dark chocolate bar or 80 g white chocolate bar daily for 14 days, rest for 7 days, and then switch to the other type of chocolate.
Read the detailed description
This is a randomized cross-over trial conducted in Chiang Mai, Thailand. The goal of this clinical trial is to examine whether consumption of dark chocolate affects cardiovascular risk factors, with the primary outcomes being blood pressure and a cardiovascular risk factor called trimethylamine N-oxide. Participants are Thai males aged 35-70 years with hypertension who live in the Chiang Mai area.
42 Participants will consume either 100 g 72% dark chocolate bar (~2.5 servings, providing ~900 mg theobromine) or 80 g white chocolate bar (~2 servings, providing 0 mg theobromine) daily for 14 days. After a 7-day wash-out period, the participant will repeat the protocol with the other intervention.
- Conditions
- Hypertension
- Being tested
- dark chocolate, white chocolate
- Keywords
- cocoa consumption, theobromine, trimethylamine-n-oxide, crossover, randomized trial, chocolate consumption
- Medical subject headings
- Hypertension
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
dark chocolateOther
Consumption of 100 g/day of 72% dark chocolate bar for 14 days consecutively
white chocolateOther
Consumption of 80 g/day of white chocolate bar for 14 days consecutively
| Study group | Role | What they receive |
|---|---|---|
| Dark chocolate | Experimental | 100 g/day of dark chocolate Receives: Other: dark chocolate |
| White chocolate | Placebo comparator | 80 g/day of white chocolate Receives: Other: white chocolate |
What is being measured
The primary outcome is the main question the study is designed to answer.
Blood pressure
Office blood pressure measured in the morning after fasting
Measured: Measured at the beginning and the end of each intervention period (14 days)
Fasting blood trimethylamine-N-oxide
Fasting blood trimethylamine-n-oxide concentrations
Measured: Measured at the beginning and the end of each intervention period (14 days)
Secondary outcomes (2)
Postprandial trimethylamine-N-oxide
Urinary trimethylamine-N-oxide concentrations at 24 and 48 hours after consumption of a test meal (3 boiled eggs)
Measured: Measured at the beginning and the end of the dark chocolate intervention (14 days)
Ankle-brachial index
Ankle-brachial index is a noninvasive test that measures the ratio of blood pressure in the ankle to the blood pressure in the arm.
Measured: From the beginning and end of each intervention period of 14 days
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted11 Feb 2025
- Study start15 Feb 2025
- Primary completion30 Apr 2025
- Study completion30 Apr 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for HypertensionStudies of the same condition, open and under way.
- 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
- Masking
- None (open label)
- Enrolment
- 53 participants (actual)
Sponsor and investigators
- Lead sponsor
- Chiang Mai University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Siraphat Taesuwan, Chiang Mai University
- Investigators
- Kongsak Boonyapranai, Doctoral degree, Principal investigator, Research Institute for Health Science, Chiang Mai University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06820944
- Sponsor's protocol ID
- 21/67
- Status last verified
- Mar 2026
- First submitted
- 6 Feb 2025
- Last updated
- 18 Mar 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 18 Mar 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Theobromine Consumption From Cocoa and Cardiovascular Risk Factors in Humans: Evidence for Health Claims
- ClinicalTrials.gov ID
- NCT06820944
- Acronym / sponsor ID
- 21/67
- Conditions
- Hypertension
- Keywords
- cocoa consumption, theobromine, trimethylamine-n-oxide, crossover, randomized trial, chocolate consumption
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 53 participants (actual)
- Lead sponsor
- Chiang Mai UniversityUniversity, hospital or other
- Study start
- 15 Feb 2025 (actual)
- Primary completion
- 30 Apr 2025 (actual)
- Study completion
- 30 Apr 2025 (actual)
- First posted
- 11 Feb 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 goal of this clinical trial is to examine whether consumption of dark chocolate affects blood pressure and a cardiovascular risk factor called trimethylamine N-oxide in Thai male participants with hypertension. The main questions it aims to answer are:
Can consumption of dark chocolate lower blood pressure? Can consumption of dark chocolate lower blood trimethylamine N-oxide?
Researchers will compare dark chocolate to white chocolate to see if the effects are due to theobromine (a key bioactive compound in dark chocolate).
Participants will consume either 100 g 72% dark chocolate bar or 80 g white chocolate bar daily for 14 days, rest for 7 days, and then switch to the other type of chocolate.
Detailed description
This is a randomized cross-over trial conducted in Chiang Mai, Thailand. The goal of this clinical trial is to examine whether consumption of dark chocolate affects cardiovascular risk factors, with the primary outcomes being blood pressure and a cardiovascular risk factor called trimethylamine N-oxide. Participants are Thai males aged 35-70 years with hypertension who live in the Chiang Mai area.
42 Participants will consume either 100 g 72% dark chocolate bar (~2.5 servings, providing ~900 mg theobromine) or 80 g white chocolate bar (~2 servings, providing 0 mg theobromine) daily for 14 days. After a 7-day wash-out period, the participant will repeat the protocol with the other intervention.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Dark chocolate | Experimental | Other: dark chocolate100 g/day of dark chocolate |
| White chocolate | Placebo comparator | Other: white chocolate80 g/day of white chocolate |
Who may qualify
- Ages
- 35 to 70 years
- Sex
- Male only
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (5 listed)
- Male
- Age between 35 to 70 years
- BMI less than 30 kg/m^2
- Systolic blood pressure between 130 to 159 mmHg or Diastolic blood pressure between 85 to 99 mmHg.
- Do not smoke.
Key exclusion criteria (7 listed)
- Cannot drink beverages and consume foods that have caffeine.
- Take medicine to lower cholesterol and triglyceride levels, treat high blood pressure, or diabetes.
- Have liver and kidney inflammation.
- Use antibiotics within 1 month of study.
- Use choline or probiotic supplements regularly within 1 month of study.
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 |
|---|---|---|
| dark chocolateConsumption of 100 g/day of 72% dark chocolate bar for 14 days consecutively | Other | Dark chocolate |
| white chocolateConsumption of 80 g/day of white chocolate bar for 14 days consecutively | Other | White chocolate |
Primary outcome
Blood pressure
Time frame: Measured at the beginning and the end of each intervention period (14 days)
Office blood pressure measured in the morning after fasting
Fasting blood trimethylamine-N-oxide
Time frame: Measured at the beginning and the end of each intervention period (14 days)
Fasting blood trimethylamine-n-oxide concentrations
2 secondary outcomes
Postprandial trimethylamine-N-oxide
Time frame: Measured at the beginning and the end of the dark chocolate intervention (14 days)
Ankle-brachial index
Time frame: From the beginning and end of each intervention period of 14 days
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 18 Mar 2026.
- Chocolate consumption and cardiometabolic disorders: systematic review and meta-analysis. BMJ, 343(7825).Link provided by the sponsor.
- The Pittsburgh Sleep Quality Index: a new instrument for psychiatric practice and research. Psychiatry Research, 28(2), 193-213.Link provided by the sponsor.
- Effect of dark chocolate on flow-mediated dilatation: Systematic review, meta-analysis, and dose-response analysis of randomized controlled trials. Clinical Nutrition ESPEN, 36, 17-27.Link provided by the sponsor.
- Effects of chocolate, cocoa, and flavan-3-ols on cardiovascular health: a systematic review and meta-analysis of randomized trials. The American Journal of Clinical Nutrition, 95(3), 740-751.Link provided by the sponsor.
- Impact of cocoa flavanols on human health. Food and Chemical Toxicology, 151, 112121.Link provided by the sponsor.
- Effect of cocoa and theobromine consumption on serum HDL-cholesterol concentrations: A randomized controlled trial. American Journal of Clinical Nutrition, 97(6), 1201-1209.Link provided by the sponsor.
- 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.
Kongsak Boonyapranai, Doctoral degree principal investigator
Research Institute for Health Science, Chiang Mai University
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing dark chocolate and white chocolate in people with Hypertension, run by Chiang Mai University at 1 site in Thailand.
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 5 inclusion and 7 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 18 Mar 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 Thailand. 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?
Blood pressure (time frame: Measured at the beginning and the end of each intervention period (14 days)). 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?
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 18 Mar 2026.