Anxiety SymptomsNCT07216729
The Effects of Probiotic Supplementation on State and Trait Stress, Anxiety, and Depression Symptoms in Stressed Adults
A study testing Lactobacillus reuteri DSM 17938 in people with Anxiety Symptoms and Perceived Stress, run by University of Colorado, Boulder at 1 site in United States.
Trial summary
The goal of this randomized controlled trial is to learn if supplementation with the probiotic Lactobacillus reuteri DSM 17938 can reduce levels of trait and state perceived stress, anxiety, and depressive symptoms compared to a placebo in a population of stressed adults ages 18-45. Read more about this study
- Who is it for?
- Ages 18 to 45 years
- Conditions the study is for
- Anxiety Symptoms, Perceived Stress, Depressive Symptoms
- What is being tested?
- Lactobacillus reuteri DSM 17938
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 150 participants
- Where
- 1 siteUnited States
- Study dates
- 20 Feb 2023to 1 Jun 2024
- 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 45 years
- All sexes
- No healthy volunteers
- Adult
Who may be able to join
- age 18 - 45
- scoring 14+ on the perceived stress scale-10 indicating medium stress or higher
- ability to provide informed consent
- willingness not to take probiotic supplements (pills, tablets, oils, etc.) other than the product provided in the clinical study until all study procedures are completed
- own a smartphone and are willing to receive study materials and complete study procedures by text
Who cannot join
- a history of gastrointestinal discomfort or surgery, urinary incontinence, cancer, toxic shock syndrome, frequent diarrhea, vital signs outside of the acceptable range (i.e., blood pressure >160/100, oral temperature >100°F, pulse >100), heart disease, heart attack, lung/respiratory disease, any pulmonary, cardiovascular, gastrointestinal, hepatic or renal functional abnormality (i.e. a medical diagnosis related to lungs, heart, stomach/intestines, liver, or kidneys), HIV, Hepatitis B, Hepatitis C, bipolar disorder, psychosis, or confirmed or suspected immunosuppression or immunodeficiency
- current (past month) alcohol or substance abuse or dependence (score of 2+ on the UNCOPE)
- consistent (e.g., 5x/week or greater) probiotic supplementation within the last month, including probiotic food products such as yogurt
- receiving antibiotics within the last month
- receiving medications that interfere with gut motility (opiates, loperamide, stool softeners)
- use of systemic antibiotics, antifungals, antivirals, or antiparasitics (intravenous, intramuscular, or oral)
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- use of oral, intravenous, intramuscular, nasal or inhaled corticosteroids
- use of cytokines or cytokine inhibitors
- use of methotrexate or immunosuppressive cytotoxic agents
- receiving immunosuppressive drugs/medications or treatment including antineoplastic therapy, post-transplantation immunosuppressive therapy, and/or radiation therapy
- participation in conflicting interventional research protocol
- unstable dietary history as defined by major changes in diet during the previous month, where the subject has eliminated or significantly increased a major food group in their diet
- female who is pregnant or lactating or reports expecting to get pregnant during the course of the study
- currently involved in the criminal justice system as a prisoner or ward of the state
Trial locations and contacts
1 site in 1 country.
United States1 site
University of Colorado Boulder, Muenzinger Psychology Building
Boulder, Colorado, 80309
About this study
Official title: Evaluating the Effects of Lactobacillus Reuteri DSM 17938 on State and Trait Stress in Stressed Adults
The goal of this randomized controlled trial is to learn if supplementation with the probiotic Lactobacillus reuteri DSM 17938 can reduce levels of trait and state perceived stress, anxiety, and depressive symptoms compared to a placebo in a population of stressed adults ages 18-45. This study also investigates several evidence-based moderators of treatment effects, evaluates whether the probiotic caused side effects, and evaluates whether effects endured at 1-month post-supplementation.
- Conditions
- Anxiety Symptoms, Perceived Stress, Depressive Symptoms
- Being tested
- Lactobacillus reuteri DSM 17938, Placebo
- Keywords
- Lactobacillus reuteri DSM 17938, Perceived stress, Anxiety, Depression, Probiotic, Randomized controlled trial
- Medical subject headings
- Anxiety Disorders, Depression
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Lactobacillus reuteri DSM 17938Dietary supplement
5 drops (100 million CFUs) daily for 46 days of L. reuteri DSM 17938 in sunflower oil, medium chain triglyceride oil, and silicon dioxide.
PlaceboOther
5 drops daily for 46 days of placebo consisting of inactive ingredients from probiotic supplement, specifically sunflower oil, medium chain triglyceride oil, and silicon dioxide.
| Study group | Role | What they receive |
|---|---|---|
| Probiotic | Experimental | 5 drops daily (100 million colony-forming units) for 46 days of Lactobacillus reuteri DSM 17938 in sunflower oil, medium chain triglyceride oil, and silicon dioxide. Receives: Dietary Supplement: Lactobacillus reuteri DSM 17938 |
| Placebo | Placebo comparator | 5 drops daily for 46 days of a placebo consisting of the inactive ingredients from the probiotic supplement, specifically sunflower oil, medium chain triglyceride oil, and silicon dioxide. Receives: Other: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change from baseline in mean trait perceived stress as assessed by PSS-10
Perceived stress scale-10 (PSS-10) administered via REDCap. Possible score range of 0 to 40, with 0-13 considered low stress, 14-26 moderate stress, and 27-40 high stress.
Measured: Baseline and the end of treatment at 46 days
State perceived stress as assessed by adapted PSS-4 using ecological momentary assessment
Perceived stress scale-4 (PSS-4) administered via REDCap and adapted for state measurement. The investigators adapted this measure for state stress by asking participants to rate the intensity of perceived stress they were experiencing in the moment, as opposed to the frequency with which they experienced perceived stress over the past month. Possible score range of 0 to 16, with higher scores indicating higher levels of state stress.
Measured: Five times per day (hourly, 12-7pm, sent via text with a 15 minute response window) during the last 5 days of supplementation, days 42 to 46, when the investigators expect participants to have reached maximum benefit
Secondary outcomes (4)
Change from baseline in mean trait anxiety symptoms as assessed by GAD-7
Generalized Anxiety Disorder-7 scale (GAD-7) administered via REDCap. Possible score range of 0 to 21, with higher scores indicating higher levels of anxiety symptoms.
Measured: Baseline and the end of treatment at 46 days
State anxiety symptoms as assessed with the SUDS using ecological momentary assessment
Subjective units of distress scale (SUDS) administered via REDCap. Possible score range of 0 to 100, with higher scores indicating higher levels of state anxiety.
Measured: Five times per day (hourly, 12-7pm, sent via text with a 15 minute response window) during the last 5 days of supplementation, days 42 to 46, when the investigators expect participants to have reached maximum benefit
Change from baseline in mean trait depressive symptoms as assessed by the PHQ-8
Patient Health Questionnaire-8 (PHQ-8) administered via REDCap. Possible score range of 0 to 24, with higher scores indicating higher levels of depression.
Measured: Baseline and the end of treatment at 46 days
State depressive symptoms as assessed by SUDS using ecological momentary assessment
Subjective Units of Distress Scale (SUDS) administered via REDCap. Possible score range of 0 to 100, with higher scores indicating higher levels of state depression.
Measured: Five times per day (hourly, 12-7pm, sent via text with a 15 minute response window) during the last 5 days of supplementation, days 42 to 46, when the investigators expect participants to have reached maximum benefit
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted15 Oct 2025
- Study start20 Feb 2023
- Primary completion6 May 2024
- Study completion1 Jun 2024
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Anxiety SymptomsStudies 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
- Supportive care
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 150 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Colorado, Boulder
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Lauren Finkelstein, University of Colorado, Boulder
- Investigators
- Lauren B Finkelstein, MA, Principal investigator, University of Colorado, Boulder
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07216729
- Sponsor's protocol ID
- 22-0234
- Status last verified
- Nov 2025
- First submitted
- 10 Oct 2025
- Last updated
- 18 Nov 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: Deidentified individual participant data (IPD) will be shared with other researchers in our lab to conduct secondary analyses. Data sharing will ensure protection of participant confidentiality.
Study at a glance
From the registry record, last updated by the sponsor on 18 Nov 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Evaluating the Effects of Lactobacillus Reuteri DSM 17938 on State and Trait Stress in Stressed Adults
- ClinicalTrials.gov ID
- NCT07216729
- Acronym / sponsor ID
- 22-0234
- Conditions
- Anxiety Symptoms, Perceived Stress, Depressive Symptoms
- Keywords
- Lactobacillus reuteri DSM 17938, Perceived stress, Anxiety, Depression, Probiotic, Randomized controlled trial
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 150 participants (actual)
- Lead sponsor
- University of Colorado, BoulderUniversity, hospital or other
- Study start
- 20 Feb 2023 (actual)
- Primary completion
- 6 May 2024 (actual)
- Study completion
- 1 Jun 2024 (actual)
- First posted
- 15 Oct 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 randomized controlled trial is to learn if supplementation with the probiotic Lactobacillus reuteri DSM 17938 can reduce levels of trait and state perceived stress, anxiety, and depressive symptoms compared to a placebo in a population of stressed adults ages 18-45. This study also investigates several evidence-based moderators of treatment effects, evaluates whether the probiotic caused side effects, and evaluates whether effects endured at 1-month post-supplementation.
Study design
- Primary purpose
- Supportive care
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, investigator)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Probiotic | Experimental | Dietary Supplement: Lactobacillus reuteri DSM 179385 drops daily (100 million colony-forming units) for 46 days of Lactobacillus reuteri DSM 17938 in sunflower oil, medium chain triglyceride oil, and silicon dioxide. |
| Placebo | Placebo comparator | Other: Placebo5 drops daily for 46 days of a placebo consisting of the inactive ingredients from the probiotic supplement, specifically sunflower oil, medium chain triglyceride oil, and silicon dioxide. |
Who may qualify
- Ages
- 18 to 45 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult
Key inclusion criteria (5 listed)
- age 18 - 45
- scoring 14+ on the perceived stress scale-10 indicating medium stress or higher
- ability to provide informed consent
- willingness not to take probiotic supplements (pills, tablets, oils, etc.) other than the product provided in the clinical study until all study procedures are completed
- own a smartphone and are willing to receive study materials and complete study procedures by text
Key exclusion criteria (14 listed)
- a history of gastrointestinal discomfort or surgery, urinary incontinence, cancer, toxic shock syndrome, frequent diarrhea, vital signs outside of the acceptable range (i.e., blood pressure >160/100, oral temperature >100°F, pulse >100), heart disease, heart attack, lung/respiratory disease, any pulmonary, cardiovascular, gastrointestinal, hepatic or renal functional abnormality (i.e. a medical diagnosis related to lungs, heart, stomach/intestines, liver, or kidneys), HIV, Hepatitis B, Hepatitis C, bipolar disorder, psychosis, or confirmed or suspected immunosuppression or immunodeficiency
- current (past month) alcohol or substance abuse or dependence (score of 2+ on the UNCOPE)
- consistent (e.g., 5x/week or greater) probiotic supplementation within the last month, including probiotic food products such as yogurt
- receiving antibiotics within the last month
- receiving medications that interfere with gut motility (opiates, loperamide, stool softeners)
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 |
|---|---|---|
| Lactobacillus reuteri DSM 179385 drops (100 million CFUs) daily for 46 days of L. reuteri DSM 17938 in sunflower oil, medium chain triglyceride oil, and silicon dioxide. | Dietary supplement | Probiotic |
| Placebo5 drops daily for 46 days of placebo consisting of inactive ingredients from probiotic supplement, specifically sunflower oil, medium chain triglyceride oil, and silicon dioxide. | Other | Placebo |
Primary outcome
Change from baseline in mean trait perceived stress as assessed by PSS-10
Time frame: Baseline and the end of treatment at 46 days
Perceived stress scale-10 (PSS-10) administered via REDCap. Possible score range of 0 to 40, with 0-13 considered low stress, 14-26 moderate stress, and 27-40 high stress.
State perceived stress as assessed by adapted PSS-4 using ecological momentary assessment
Time frame: Five times per day (hourly, 12-7pm, sent via text with a 15 minute response window) during the last 5 days of supplementation, days 42 to 46, when the investigators expect participants to have reached maximum benefit
Perceived stress scale-4 (PSS-4) administered via REDCap and adapted for state measurement. The investigators adapted this measure for state stress by asking participants to rate the intensity of perceived stress they were experiencing in the moment, as opposed to the frequency with which they experienced perceived stress over the past month. Possible score range of 0 to 16, with higher scores indicating higher levels of state stress.
4 secondary outcomes
Change from baseline in mean trait anxiety symptoms as assessed by GAD-7
Time frame: Baseline and the end of treatment at 46 days
State anxiety symptoms as assessed with the SUDS using ecological momentary assessment
Time frame: Five times per day (hourly, 12-7pm, sent via text with a 15 minute response window) during the last 5 days of supplementation, days 42 to 46, when the investigators expect participants to have reached maximum benefit
Change from baseline in mean trait depressive symptoms as assessed by the PHQ-8
Time frame: Baseline and the end of treatment at 46 days
State depressive symptoms as assessed by SUDS using ecological momentary assessment
Time frame: Five times per day (hourly, 12-7pm, sent via text with a 15 minute response window) during the last 5 days of supplementation, days 42 to 46, when the investigators expect participants to have reached maximum benefit
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 Nov 2025.
- Prior pre-registration on Open Science Framework, initially submitted prior to starting data collectionLink provided by the sponsor.
- Individual participant dataSharing planned: Yes. Deidentified individual participant data (IPD) will be shared with other researchers in our lab to conduct secondary analyses. Data sharing will ensure protection of participant confidentiality.
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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.
Lauren B Finkelstein, MA principal investigator
University of Colorado, Boulder
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Lactobacillus reuteri DSM 17938 in people with Anxiety Symptoms and Perceived Stress, run by University of Colorado, Boulder at 1 site in United States.
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 14 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 Nov 2025. 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 United States. 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?
Change from baseline in mean trait perceived stress as assessed by PSS-10 (time frame: Baseline and the end of treatment at 46 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 Nov 2025.