A Study to See if an Energy Drink With Caffeine and Green Tea Increases Fat Burning When Exercising

April 13, 2026 updated by: RDC Clinical Pty Ltd

Influence of Caffeine and Green Tea Extracts Consumption on Basal, Peri- and Post-exercise Fat Oxidation

The goal of this study is to evaluate the influence of consuming a drink containing a combination of caffeine and green tea extracts on fat oxidation responses at rest, during and after a period of endurance type exercise.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

This study investigates whether consuming an energy drink containing caffeine and green tea extract before exercise increases fat burning (oxidation) compared with a placebo drink. Healthy, moderately active adults will attend three visits at clinic over 3-5 weeks. The first visit determines each participant's individual exercise intensity that maximises fat use during cycling. At two subsequent visits, participants will consume either the active drink or a placebo before completing a 30-minute cycling session at their personalised intensity. Fat and carbohydrate use, heart rate, blood pressure, and subjective responses will be measured at rest, during exercise, and after exercise using a double-blind, crossover design.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
40

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 4

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • Australia
    • Queensland
      • Southport, Queensland, Australia, 4222
        • Recruiting
        • Griffith University, Gold Coast Campus

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Passing the Exercise and Sport Science Australia adult pre-exercise screening system (APSS) stage 1 & 2 (see appendix 4).
  • Between the ages of 18 and 45,
  • Not sedentary, and not completing more than 150 minutes of low and/or moderate and/or or vigorous intensity endurance exercise a week,
  • Ability to commit to in principle fulfilment of all 3 trial visits,
  • No history of coagulopathy e.g., DVT, stroke,
  • No known heart disease,
  • No known pancreatic insufficiency,
  • No known inflammatory bowel disease, or prior bowel resection or bypass surgery (excluding gastric banding and sleeve),
  • BMI of 22.0 to 34.9 kg/m2,
  • No known allergies to caffeine or green tea extract,
  • No known type I or II diabetes,
  • No uncontrolled concurrent illness,
  • No known current pregnancy or breastfeeding women
  • No current regular consumption of supplements (>2 times a week) or foods and drinks containing caffeine and/or green tea extracts (>2 times per day, weekly).
  • Agree not to consume caffeine for 12-hours prior to the clinic visit.

Exclusion Criteria:

  • Triggering any of the exclusion screening criteria as outlined below, and in compliment with the Exercise and Sport Science Australia adult pre-exercise screening system (APSS).
  • Under the age of 18 or over the age of 45,
  • Sedentary, or completing over 150 minutes of low and/or moderate and/or or vigorous intensity endurance exercise a week,
  • Inability to commit to in principle fulfilment of all 3 trial visits,
  • History of coagulopathy e.g., DVT, stroke,
  • Known heart disease,
  • Known pancreatic insufficiency,
  • Known inflammatory bowel disease, or prior bowel resection or bypass surgery (excluding gastric banding and sleeve),
  • BMI < 22.0 or > 34.9 kg/m2,
  • Known allergies to caffeine or green tea extract,
  • Known type I or II diabetes,
  • Uncontrolled concurrent illness,
  • Taking GLP-1 agonists, caffeine, or any other medication known to affect metabolism.
  • Known current pregnancy or breastfeeding women.
  • Currently regularly consuming supplements, foods or drinks containing a caffeine and green tea extract blend, or not willing to abstain for the study

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Quadruple

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Active
Two 355 mL cans of "XS Energy + BURN" drink containing caffeine and green tea extract.
Dietary supplement: Active (Green tea and caffeine)
Two 355 mL cans of "XS Energy + BURN" drink containing caffeine and green tea extract.
Other Names:
  • XS Energy + BURN
Other: Placebo
Two 355 mL cans of placebo drink but without the active ingredients (caffeine and green tea extract).
Other: Placebo
Two 355 mL cans of placebo drink but without the active ingredients (caffeine and green tea extract).

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Fat oxidation as measured by indirect calorimetry
Time Frame: Baseline to 30 mins post exercise
Change from baseline to the end of the study period in Fat oxidation as measured by indirect calorimetry (metabolic cart); baseline (pre-drink), post-drink (pre-exercise), time sequence e.g., every 5-min during exercise, 10, 20 and 30-min post-exercise. Change from baseline & total. Fat oxidation will be measured continuously throughout the exercise and the 30-min post-exercise window, to facilitate total, and any other temporal fat oxidation timepoints.
Baseline to 30 mins post exercise

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Carbohydrate oxidation; indirect calorimetry
Time Frame: Baseline to 30 mins post exercise
Change from baseline to the end of the study period in Carbohydrate oxidation; indirect calorimetry; same timing as fat oxidation (baseline (pre-drink), post-drink (pre-exercise), time sequence e.g., every 5-min during exercise, 10, 20 and 30-min post-exercise.). Change from baseline & total.
Baseline to 30 mins post exercise
Respiratory exchange ratio; indirect calorimetry
Time Frame: Baseline to 30 mins post exercise
Change from baseline to the end of the study period in Respiratory exchange ratio; indirect calorimetry; same timing as fat oxidation (baseline (pre-drink), post-drink (pre-exercise), time sequence e.g., every 5-min during exercise, 10, 20 and 30-min post-exercise). Change from baseline & total
Baseline to 30 mins post exercise
Exercise efficiency; indirect calorimetry
Time Frame: Baseline to 30 mins post exercise
Change from baseline to the end of the study period in Exercise efficiency; indirect calorimetry; time sequence during exercise e.g., every 5-min. Change from the beginning of exercise & average
Baseline to 30 mins post exercise

Other Outcome Measures

Other Outcome Measures

For clinical trials, a planned measurement described in the protocol that is used to determine the effect of an intervention/treatment on participants. For observational studies, a measurement or observation that is used to describe patterns of diseases or traits, or associations with exposures, risk factors, or treatment. Types of outcome measures include primary outcome measure and secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Tertiary: Compliance monitoring
Time Frame: Baseline to end of study period (week 5)
Compliance monitoring for adherence to clinical trial components e.g. consumed volume of investigational product; ability to complete the necessary duration (30 mins) and intensity (at fat max) of exercise; adherence to immediate pre-trial control procedures of no caffeine or green tea extract in the 12 hours leading up to the experimental, arrival at the laboratory after an overnight fast
Baseline to end of study period (week 5)
Tertiary: Adverse Event monitoring
Time Frame: Baseline to end of study period (week 5)
Adverse events will be monitored throughout the study across the study periods.
Baseline to end of study period (week 5)
Tertiary: Perceived gastrointestinal (dis)comfort questionnaire
Time Frame: Baseline to end of study (week 5)
Change from baseline to the end of the study period in Perceived gastrointestinal (dis)comfort; measured via a questionnaire.
Baseline to end of study (week 5)
Tertiary: Perceived satiety / hunger
Time Frame: Baseline to end of study period (week 5)
Change from baseline to the end of the study period in Perceived satiety / hunger; measured via questionnaire.
Baseline to end of study period (week 5)
Tertiary: Perceived exercising exertion
Time Frame: Baseline to end of study period (week 5)
Change from baseline to the end of the study period in Perceived exercising exertion; measured via questionnaire.
Baseline to end of study period (week 5)
Tertiary: heart rate
Time Frame: Baseline to end of study period (week 5)
Change from baseline to the end of the study period in heart rate. Pre, during and post exercise heart rate.
Baseline to end of study period (week 5)
Tertiary: blood pressure
Time Frame: Baseline to end of study period (week 5)
Change from baseline to the end of the study period in blood pressure. Pre, during and post exercise blood pressure.
Baseline to end of study period (week 5)
Tertiary: Safety via AE monitoring
Time Frame: Baseline to end of study period (week 5)
Change from baseline to the end of the study period in safety via AE monitoring.
Baseline to end of study period (week 5)
Tertiary: Anthropometry - BMI
Time Frame: Baseline to end of study period (week 5)
Change from baseline to the end of the study period in BMI.
Baseline to end of study period (week 5)
Tertiary: Anthropometry - weight
Time Frame: Baseline to end of study period (week 5)
Change from baseline to the end of the study period in weight.
Baseline to end of study period (week 5)
Tertiary: Anthropometry - waist circumference
Time Frame: Baseline to end of study period (week 5)
Change from baseline to the end of the study period in waist circumference.
Baseline to end of study period (week 5)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
RDC Clinical Pty Ltd

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
Amway Corp

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
March 26, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 1, 2026

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 1, 2026

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
January 5, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
February 19, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
February 27, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
April 16, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 13, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
January 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • GRIFEX

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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Drug Interventions

Conditions

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Drug Interventions

Dietary Supplements

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