Healthy Adult ParticipantsNCT07867496
Exploration of Tolerability and Dose Responses for a Yeast-based Probiotic
A study testing 9.9 x 10^7 Pichia kluyveri PK88 and 1 x 10^8 Pichia kluyveri PK88 in people with Healthy Adult Participants and Gut Health, run by Colorado State University at 1 site in United States.
Trial summary
The purpose of this study is to evaluate the tolerability and efficacy of a yeast-based dietary supplement on gastrointestinal, mental, and skin health. Yeasts are naturally present on fruits and plants, and are used to bake bread, beer and wine. Read more about this study
- Who is it for?
- Ages 18 to 75 yearsHealthy volunteers can take part
- Conditions the study is for
- Healthy Adult Participants, Gut Health
- What is being tested?
- 9.9 x 10^7 Pichia kluyveri PK88 and 1 x 10^8 Pichia kluyveri PK88
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 50 participants
- Where
- 1 siteUnited States
- Study dates
- 1 Nov 2026to 1 Mar 2028
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
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 75 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- between 18-75 years old
- BMI <30 kg/m2
- mild/moderate gastrointestinal distress
Who cannot join
- Have taken antibiotics within two months of enrollment in the study
- Are currently taking statins, metformin, NSAIDs, and MAO inhibitors or other medications that could interfere with study outcomes, as determined by the study PI
- Have a current diagnosis of cancer, liver or kidney disease, gastrointestinal diseases (including Celiac, Crohn's, Ulcerative Colitis), and cardiometabolic disorders (cardiovascular disease, diabetes, etc.)
- Are pregnant or breastfeeding, or actively trying to lose weight
- Use excessive alcohol
- Use of supplements containing probiotics at any dose or if you are participating in other studies that may interfere with the bacteria in your gut.
- Unable or unwilling to consume capsules, provide stool or blood samples, track bowel movements and symptoms, and attend scheduled clinic visits.
- Have allergies to study treatments or medical supplies (eg. Latex, yeast, cellulose)
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site
Colorado State University
Fort Collins, Colorado, 80521
Tiffany Weir, PhD, 970-215-7571, tiffany.weir@colostate.edu
Tiffany Weir, PhD
About this study
The purpose of this study is to evaluate the tolerability and efficacy of a yeast-based dietary supplement on gastrointestinal, mental, and skin health. Yeasts are naturally present on fruits and plants, and are used to bake bread, beer and wine. Some of these yeasts are commonly consumed and may actually benefit your gut health. The supplemental yeast could strengthen the gut lining or help good bacteria in the gut grow better.
In this study, the investigators will look at how two doses of a yeast-based supplement impacts gut health, bowel movement consistency, and mental health. The study will last 17 weeks and consist of 7 clinic visits (1 screening visit and 6 test visits).
Read the detailed description
This study will take place at Colorado State University in Fort Collins, Colorado, USA. It will last approximately 17 weeks. This is a randomized, double-blind 3-arm crossover study with three treatments (placebo and two doses of Pichia kluyveri). The treatments will be taken for 4 weeks in a random order by every participant. Each treatment phase is separated by a 2-week washout. The first visit is a screening visit, where investigators will determine eligibility. Visit 2-7 are test visits where investigators will collect information on height, weight, waist, and hip measurements. Blood pressure will also be measured and the visit will conclude with a venous blood draw. During this visit, participants will also complete questionnaires about gut, mental, and skin health, menopause symptoms, and physical activity. A stool sample and bowel movement and diet records will be completed at home.
- Conditions
- Healthy Adult Participants, Gut Health
- Being tested
- 9.9 x 10^7 Pichia kluyveri PK88, 1 x 10^8 Pichia kluyveri PK88, Placebo
- Keywords
- Probiotic, Gut health, Dietary Supplement, Yeast-based Probiotic
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
9.9 x 10^7 Pichia kluyveri PK88Dietary supplement
9.9 x 10^7 Pichia kluyveri in microcrystalline cellulose and hypromellose
1 x 10^8 Pichia kluyveri PK88Dietary supplement
1 x 10^8 Pichia kluyveri in microcrystalline cellulose and hypromellose
PlaceboDietary supplement
Placebo - cellulose and hypromellose
| Study group | Role | What they receive |
|---|---|---|
| Pichia kluyveri 9.9 x 10^7 | Experimental | Not described Receives: Dietary Supplement: 9.9 x 10^7 Pichia kluyveri PK88 |
| Pichia kluyveri 1 x 10^8 | Experimental | Not described Receives: Dietary Supplement: 1 x 10^8 Pichia kluyveri PK88 |
| Placebo | Placebo comparator | Not described Receives: Dietary Supplement: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Severity of gastrointestinal symptoms using the Gastrointestinal Symptom Rating Scale (GSRS)
The Gastrointestinal Symptom Rating Scale (GSRS) is a widely used tool for measuring gastrointestinal symptoms across five domains. The GSRS is scored between "No discomfort" and "Very severe discomfort"
Measured: 4 weeks
Secondary outcomes (1)
Systemic inflammation indicated by circulating Tumor Necrosis Factor Alpha
Tumor necrosis factor alpha, or TNF-a, is an inflammatory cytokine that is implicated in many diseases.
Measured: 4 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted9 Oct 2026
- Study start1 Nov 2026 (estimated)
- Primary completion31 Oct 2027 (estimated)
- Study completion1 Mar 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Healthy Adult ParticipantsStudies 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
- Crossover
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 50 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Colorado State University
- Sponsor type
- University, hospital or other
- Collaborators
- Biohm Technologies
- Responsible party
- Principal investigator, Tiffany Weir, Colorado State University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07867496
- Sponsor's protocol ID
- 8533
- Status last verified
- Oct 2026
- First submitted
- 5 Oct 2026
- Last updated
- 22 Oct 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 22 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Exploration of Tolerability and Dose Responses for a Yeast-based Probiotic
- ClinicalTrials.gov ID
- NCT07867496
- Acronym / sponsor ID
- 8533
- Conditions
- Healthy Adult Participants, Gut Health
- Keywords
- Probiotic, Gut health, Dietary Supplement, Yeast-based Probiotic
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 50 participants (estimated)
- Lead sponsor
- Colorado State UniversityUniversity, hospital or other
- Collaborators
- Biohm Technologies
- Study start
- 1 Nov 2026 (estimated)
- Primary completion
- 31 Oct 2027 (estimated)
- Study completion
- 1 Mar 2028 (estimated)
- First posted
- 9 Oct 2026 (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 purpose of this study is to evaluate the tolerability and efficacy of a yeast-based dietary supplement on gastrointestinal, mental, and skin health. Yeasts are naturally present on fruits and plants, and are used to bake bread, beer and wine. Some of these yeasts are commonly consumed and may actually benefit your gut health. The supplemental yeast could strengthen the gut lining or help good bacteria in the gut grow better.
In this study, the investigators will look at how two doses of a yeast-based supplement impacts gut health, bowel movement consistency, and mental health. The study will last 17 weeks and consist of 7 clinic visits (1 screening visit and 6 test visits).
Detailed description
This study will take place at Colorado State University in Fort Collins, Colorado, USA. It will last approximately 17 weeks. This is a randomized, double-blind 3-arm crossover study with three treatments (placebo and two doses of Pichia kluyveri). The treatments will be taken for 4 weeks in a random order by every participant. Each treatment phase is separated by a 2-week washout. The first visit is a screening visit, where investigators will determine eligibility. Visit 2-7 are test visits where investigators will collect information on height, weight, waist, and hip measurements. Blood pressure will also be measured and the visit will conclude with a venous blood draw. During this visit, participants will also complete questionnaires about gut, mental, and skin health, menopause symptoms, and physical activity. A stool sample and bowel movement and diet records will be completed at home.
Study design
- Primary purpose
- Supportive care
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind (participant, investigator)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| Pichia kluyveri 9.9 x 10^7 | Experimental | Dietary Supplement: 9.9 x 10^7 Pichia kluyveri PK88 |
| Pichia kluyveri 1 x 10^8 | Experimental | Dietary Supplement: 1 x 10^8 Pichia kluyveri PK88 |
| Placebo | Placebo comparator | Dietary Supplement: Placebo |
Who may qualify
- Ages
- 18 to 75 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (3 listed)
- between 18-75 years old
- BMI <30 kg/m2
- mild/moderate gastrointestinal distress
Key exclusion criteria (8 listed)
- Have taken antibiotics within two months of enrollment in the study
- Are currently taking statins, metformin, NSAIDs, and MAO inhibitors or other medications that could interfere with study outcomes, as determined by the study PI
- Have a current diagnosis of cancer, liver or kidney disease, gastrointestinal diseases (including Celiac, Crohn's, Ulcerative Colitis), and cardiometabolic disorders (cardiovascular disease, diabetes, etc.)
- Are pregnant or breastfeeding, or actively trying to lose weight
- Use excessive alcohol
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 |
|---|---|---|
| 9.9 x 10^7 Pichia kluyveri PK889.9 x 10^7 Pichia kluyveri in microcrystalline cellulose and hypromellose | Dietary supplement | Pichia kluyveri 9.9 x 10^7 |
| 1 x 10^8 Pichia kluyveri PK881 x 10^8 Pichia kluyveri in microcrystalline cellulose and hypromellose | Dietary supplement | Pichia kluyveri 1 x 10^8 |
| PlaceboPlacebo - cellulose and hypromellose | Dietary supplement | Placebo |
Primary outcome
Severity of gastrointestinal symptoms using the Gastrointestinal Symptom Rating Scale (GSRS)
Time frame: 4 weeks
The Gastrointestinal Symptom Rating Scale (GSRS) is a widely used tool for measuring gastrointestinal symptoms across five domains. The GSRS is scored between "No discomfort" and "Very severe discomfort"
1 secondary outcome
Systemic inflammation indicated by circulating Tumor Necrosis Factor Alpha
Time frame: 4 weeks
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 22 Oct 2026.
- 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.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing 9.9 x 10^7 Pichia kluyveri PK88 and 1 x 10^8 Pichia kluyveri PK88 in people with Healthy Adult Participants and Gut Health, run by Colorado State University 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 3 inclusion and 8 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: opening soon, as of the sponsor's last update on 22 Oct 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 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?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Tiffany L Weir, PhD (970-215-7571, tiffany.weir@colostate.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Severity of gastrointestinal symptoms using the Gastrointestinal Symptom Rating Scale (GSRS) (time frame: 4 weeks). 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 22 Oct 2026.