Stress relief in a pill? new study tests theanine
NCT ID NCT05854017
First seen Jun 24, 2026 · Last updated Aug 27, 2026 · Updated 3 times
Summary
This study tests whether a theanine supplement can reduce stress, anxiety, and improve sleep in adults who report moderate to high stress. 104 participants will take either the supplement or a placebo for a period of time. Researchers will measure changes using stress and anxiety questionnaires.
What this could mean
Our plain-language read of the trial. This is informational only, not medical advice or a prediction.
- Active substance
- theanine dietary supplement
- What this could lead to
- If it works, this could offer a natural option for managing everyday stress and improving mood and sleep.
- What could go wrong
- This is a small, early-stage study with no phase, so results may not be conclusive. The supplement may work no better than a placebo.
This is an AI summary of the original study and may miss details. Read our disclaimer.
Study facts
What this study's own registry entry says, in plain language.
- Phase
-
Not a phased trial
Phase numbers describe drug development. The registry uses this when they do not apply, as it does for trials of devices, procedures or behaviour changes, and for observational studies.
- Participants
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104 people
The number who actually took part.
- Started
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Feb 2023
- Finished
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May 2025
- Lead sponsor
-
A company
The lead sponsor is a pharmaceutical, biotech, or medical-device company.
Who can take part
This study's own entry requirements. Only the study team can say for certain whether you qualify.
- Ages
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21 to 65 years
- Sex
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Anyone
- Healthy volunteers
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Accepted
You do not need to have the condition being studied to take part.
Show the full entry requirements Hide the full entry requirements
Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.
Inclusion Criteria: 1. Ambulatory, male or female, 21-65 years of age 2. A BMI of 18.5-34.9 3. Admits to having occasional periods of moderate or severe stress on the screening questionnaire 4. Indicating a PSS-14 score \> 19 (identification as having moderate or high perceived stress) 5. Have personal access to and able to operate a smartphone, tablet, or computer with enough memory to accommodate additional application(s) and have a reliable internet service 6. Able to take a saliva specimen and store it immediately in a freezer before breakfast at three different times during the study 7. Generally healthy and having no difficulty swallowing a tablet 8. Employed in a work setting, at-home or in a caregiver role and has regular daytime work hours or shifts, if employed (regular shift excludes night shift workers and those with rotating shifts) with no anticipated changes in the schedule, if enrolled 9. Has been generally weight stable for the past six months (+/- 6 lbs.) 10. Willing and able to give written informed consent 11. Clearly understand and are willing to comply with the study procedures and requirements 12. Willing and able to comply with all study procedures, including following recommendations to maintain their usual diet and regular activity, as per protocol 13. Able to communicate and read in the English language 14. Are not currently taking any supplements or foods containing L-theanine or D-theanine within 30 days before Screening and will not for the duration of the study Exclusion Criteria: 1. Not having the basic skills needed to operate a smartphone, tablet, or computer 2. Having smoked any cigarette, electronic cigarette, cigar, pipe, or used a recreational drug as well as any product containing cannabidiol (CBD) or tetrahydrocannabinol (THC) in the past 30 days prior to Screening 3. Having donated blood within 30 days before Screening 4. Having been diagnosed with dysphagia or difficulty swallowing 5. Having participated in another study within 30 days prior to Screening 6. Being pregnant, planning on becoming pregnant during study participation or refusing to indicate willingness to use a medically acceptable form of birth control, if applicable, during study participation, or breast feeding 7. Are participating in a stress management program and will not for the duration of the study participation 8. Unable to avoid any form of intense exercise or a significant change in exercise routine during the day of saliva specimen collection 9. Currently taking any supplements containing L-theanine or D-theanine within the past 30 days before Screening 10. Currently taking supplements including melatonin, 5-hydroxytryptophan, Calamus, California poppy, St. John's wort, S-adenosylmethionine (SAM-E), catnip, hops, kava, valerian, Jamaican dogwood, skullcap, yerba mansa, Hawaiian baby woodrose, L-theanine, magnesium, or any other supplement for stress, burnout, mood, or sleep. These may preclude participation in the study dependent the judgment of the Study Investigator/Sub-Investigator 11. Having been diagnosed, received medical treatment, taking medications or supplements daily for the following medical condition(s): * Stress disorder (including post-traumatic stress disorder (PTSD) * Sleep disorder (including insomnia diagnosed by a physician) * Psychiatric disorder. These may preclude participation in the study dependent on the judgment of the Study Investigator/Sub-Investigator. * Acute or chronic inflammatory or autoimmune disease * Active infection * Active periodontal disease 12. Presence of active or recurring clinically significant conditions as follows: * Diabetes mellitus (except on a stable dose of Metformin up to 1000 mg per day only for managing the diabetes mellitus for \> 3 months before Screening, unlikely to change medication or dose during the study, and under the care of a physician having seen the physician within 6 months before Screening) * Endocrine disease (other than diabetes mellitus) * Eating disorder * Cardiovascular disease including heart and blood vessel disease, arrhythmia, heart attack, stroke, or heart valve problem * Gastrointestinal disease including gallbladder problems, gallstones, or biliary tract obstruction * Thyroid disease (except on a stable dose of medication for ≥ 3 months before Screening and unlikely to change medication or dose during the study) * Hypertension (except on a stable dose of medication for ≥ 3 months before Screening and unlikely to change medication or dose during the study) * Neurologic condition/disease * Cancer (including skin cancer) which has been treated ≥ 5 years before Screening or at the discretion of the Study Investigator/Sub-Investigator * Liver, pancreatic, and kidney disease * Pulmonary disease * Blood coagulation disorder or other hematologic disease * Any other condition or medication that may preclude study participation in the judgement of the Study Investigator/Sub-Investigator 13. Currently taking or having taken within the 30 days before Screening any hormone replacement therapy, except those utilized as a method of birth control and which have been taken for \> 3 months with no anticipated change for the duration of the study period 14. Having had a surgical procedure or having an internal medical device which, in the judgment of the Study Investigator/Sub-Investigator, would preclude participation in the study 15. Currently consumes more than 4 standard alcoholic drinks per week for women and 7 drinks per week for men (a standard alcoholic drink is defined as one bottle/can of beer, one glass of wine, or one ounce of hard liquor) 16. Unable or unwilling to avoid consuming grapefruit juice or fresh grapefruit, Seville oranges, and tangelos for the duration of the study period 17. History of known or suspected substance abuse (e.g., alcohol, opiates, benzodiazepines, or amphetamines) 18 Having any other circumstance that may preclude study participation in the judgment of the Study Investigator/Sub-Investigator, including use of other nutritional supplements, which will be evaluated on a case-by-case basis
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Conditions
The condition(s) this trial relates to.
As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
Contacts and locations
Locations
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Life Extension Clinical Research, Inc.
Fort Lauderdale, Florida, 33304, United States
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