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Completed

NCT Number: NCT05928195

Acute Effects of Organic Guayusa Extract

Guayusa extract is a caffeinated tea leaf unique blend of antioxidants and caffeine. It is marketed as an ingredient that can help support energy and performance with potential health-related benefits. It has also been indicated as being as safe as any other existing teas (i.e., green tea). However, no studies have previous studied the dose-response effects of guayusa extract for supporting cognitive function, mood, metabolism, nor its effects on resting heart rate, blood pressure, and electrocardiogram characteristics.

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Key information

Age range

18 year–45 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Integrative Laboratory of Applied Physiology and Lifestyle Medicine

Iowa City, Iowa, 52242, United States

About this study

Guayusa extract is a caffeinated Amazonian 'super-leaf' belonging to the holly species that contains a unique blend of polyphenol antioxidants and caffeine (~20% caffeine, 30% chlorogenic acids, 5% catechins). It is also remarkably low in tannins which are responsible for the bitter taste found in most teas - giving it a sweet flavor profile. As such, it is marketed as an ingredient that can help support energy and performance (e.g., via caffeine content) with potential health-related benefits due to its antioxidant properties. Indeed, ingredients such as these are often consumed by individuals prior to exercise in order to help improve neurocognitive performance, mood, or otherwise to support health-related goals such as metabolism. Whereas several studies have suggested that caffeine and chlorogenic acid consumption may improve performance, mood, and concentration, and some evidence in animals have linked catechin consumption to improved health outcomes, no studies have previous studied whether guayusa extract supplementation helps to support these, nor has the dose-effectiveness been tested, in humans.

In this study, the effects of acute dietary supplementation with two different doses of botanical organic guayusa extract on neurocognitive/motor-cognitive performance, mood, focus, and jitteriness, resting metabolism, and resting heart rate, blood pressure, and electrocardiogram characteristics will be examined.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • 18-45 years, inclusive
  • Physically active (>=150 min/wk or >=75 min/wk Moderate or Vigorous PA) for >=3 months
  • BMI <= 30 kg/m2
  • Otherwise healthy
  • Habitual caffeine consumption >=200 mg/day OR 1-week washout of current caffeine usage prior to participation

Exclusion criteria

  • Current injury or illness that precludes exercise participation
  • Current nicotine or cannabis use
  • Use of prescription ADD/ADHD, anti-depressant, or other central acting medication, or previously diagnosed ADD/ADHD, clinically depressed, or generalized anxiety disorder
  • Current taking prescription stimulants (i.e., Adderall, Ritalin, Vyvanse, etc.)
  • Participants with a history of metabolic, hepatorenal, musculoskeletal, autoimmune, or neurologic disease; or currently taking thyroid, hormonal, hyperlipidemic, hypoglycemic, anti-hypertensive, anti-inflammatory, or anti-coagulant medications.
  • Treated for Metabolic Syndrome or having been clinically diagnosed with, or taking medication for a cardiometabolic-disorder (e.g., Pre-diabetes, Type II diabetes, high blood pressure, obesity, hypercholesterolemia, etc.)
  • Currently pregnant or lactating
  • Diagnosed allergy to any ingredient present within the study treatments
  • Current competitive NCAA athlete
  • Inability or unwillingness to comply with the controls and conditions of the study

Treatment and study plan

Acute Moderate-Dose Guayusa Extract Supplementation

Dietary Supplement

Participants will consume two vegan capsules with one capsule containing 600 mg AmaTea® and 1 containing 600 mg dextrose.

Acute High-Dose Guayusa Extract Supplementation

Dietary Supplement

Participants will consume two vegan capsules with each capsule containing 600 mg AmaTea® (1200 mg total).

Placebo

Dietary Supplement

Participants will consume two vegan capsules with each capsule containing 600 mg dextrose (1200 mg total).

Primary outcomes

  1. Mood

    Time frame: 90-minutes Post-supplementation

    Calculated as Total Mood Disturbance (arbitrary units) using the Profile of Mood States Short Form Questionnaire.

  2. Psychomotor Speed

    Time frame: 60-minutes Post-supplementation

    How well participant perceived, attends, responds to visual-perceptive information, and performs motor speed and fine motor coordination. Calculated as the sum of finger taps in finger tapping test and correct responses in the symbol digit coding test.

  3. Executive Function

    Time frame: 60-minutes Post-supplementation

    How well participant recognized rules, categories, and manages or navigates rapid decisions making. Calculated as the differences between Shifting Attention Test Correct Responses and Errors.

Secondary outcomes

  1. Jitteriness

    Time frame: 90-minutes Post-supplementation

    Participants will describe how jittery they feel after supplemention using a 0-100 mm visual analog scale.

  2. Focus

    Time frame: 90-minutes Post-supplementation

    Participants will describe how focused they feel after supplemention using a 0-100 mm visual analog scale.

  3. Energy

    Time frame: 90-minutes Post-supplementation

    Participants will describe how energetic they feel after supplemention using a 0-100 mm visual analog scale.

  4. Resting Metabolic Rate

    Time frame: 50 minutes post-supplementation

    Resting metabolic rate (kcal/min) will be quantified from resting, fasted analyses of pulmonary gas exchange.

  5. Resting Fat Oxidation

    Time frame: 50 minutes post-supplementation

    Resting fat oxidation (g/min) will be quantified from resting, fasted analyses of pulmonary gas exchange.

  6. Resting Heart Rate

    Time frame: -10 minutes before supplementation, 40 minutes post-supplementation

    Heart rate (bpm) will be quantified from a standard 12-lead ECG

  7. Resting Blood Pressure

    Time frame: -10 minutes before supplementation, 40 minutes post-supplementation

    Systolic, diastolic, and pulse pressures (mmHg) will be quantified from brachial artery via automated sphygmomanometer.

  8. QTc Interval

    Time frame: -10 minutes before supplementation, 40 minutes post-supplementation

    QTc Interval (ms) will be quantified from a standard 12-lead ECG

  9. Motor-Cognitive Reaction Time

    Time frame: 100-minutes Post-supplementation

    Motor-cognitive reaction times (ms) will be quantified from motor cognitive (reactionary hop) tests

  10. Sustained Attention

    Time frame: 60-minutes Post-supplementation

    How well a subject can direct and focus cognitive activity on specific stimuli. Derived from performance on the 4-part continuous performance task test.

  11. Working Memory

    Time frame: 60-minutes Post-supplementation

    How well a subject can perceive and attend to symbols using short-term memory processes.

  12. Cognitive Flexibility

    Time frame: 60-minutes Post-supplementation

    How well subject is able to adapt to rapidly changing and increasingly complex set of directions and/or to manipulate the information. Assessed from the Shifting Attention Task and Stoop Test as the Shifting Attention Task Correct Responses - Shifting Attention Task Incorrect Responses and Stroop Commission Errors.

Other outcomes

  1. Vigor

    Time frame: 90-minutes Post-supplementation

    Vigor will be quantified using the Profile of Mood State Short Form Questionnaire.

  2. Tension

    Time frame: 90-minutes Post-supplementation

    Tension will be quantified using the Profile of Mood State Short Form Questionnaire.

  3. Fatigue

    Time frame: 90-minutes Post-supplementation

    Fatigue will be quantified using the Profile of Mood State Short Form Questionnaire.

  4. Anger

    Time frame: 90-minutes Post-supplementation

    Anger will be quantified using the Profile of Mood State Short Form Questionnaire.

  5. Confusion

    Time frame: 90-minutes Post-supplementation

    Confusion will be quantified using the Profile of Mood State Short Form Questionnaire.

  6. Stress

    Time frame: 90-minutes Post-supplementation

    Stress will be quantified using the Profile of Mood State Short Form Questionnaire.

  7. Composite Memory

    Time frame: 60-minutes Post-supplementation

    How well subject can recognize, remember, and retrieve words and geometric figures. Assessed as a composite performance indicator during the Verbal Memory and Visual Memory Tests.

  8. Reaction Time

    Time frame: 60-minutes Post-supplementation

    How quickly the subject can react, in milliseconds, to a simple and increasingly complex direction set.

  9. Complex Attention

    Time frame: 60-minutes Post-supplementation

    Ability to track and respond to a variety of stimuli over lengthy periods of time and/or perform mental tasks requiring vigilance quickly and accurately.

  10. Reasoning

    Time frame: 60-minutes Post-supplementation

    How well is subject able to recognize, reason and respond to non-verbal visual-abstract stimuli. Assessed from the non-verbal reasoning test as the difference between the number of correct responses and commission errors.

Sponsors and collaborators

Lead sponsor

Nathaniel Jenkins

Other

Registry information

Official study title

Acute, Dose-Response Effects of Organic Guayusa Extract on Cognitive Performance, Mood, Resting Metabolism, and Blood Pressure, Heart Rate, and Heart Electrical Activity

Important dates

Study start
2022
Primary completion
2022
Study completion
2023
First posted
Jul 3, 2023
Registry last updated
Jul 5, 2023

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.