Upper Respiratory SymptomsNCT07782983
Multi-Strain Probiotic Supplementation, Salivary Immunity, and Upper Respiratory Symptoms in Trained Athletes
A study testing Multi-Strain Probiotic in people with Upper Respiratory Symptoms and Mucosal Immunity, run by University of Ulster at 1 site in United Kingdom.
Trial summary
This completed external pilot study assessed the feasibility of conducting a randomised, double-blind, placebo-controlled trial of four-week multi-strain probiotic supplementation in trained athletes. Read more about this study
- Who is it for?
- Ages 18 to 40 yearsHealthy volunteers can take part
- Conditions the study is for
- Upper Respiratory Symptoms, Mucosal Immunity
- What is being tested?
- Multi-Strain Probiotic
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 15 participants
- Where
- 1 siteUnited Kingdom
- Study dates
- 13 May 2025to 19 Dec 2025
- 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 40 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Male trained athletes aged 18-40 years.
- Regularly participating in structured training and/or competitive sport.
- Apparently healthy at enrolment, with no acute illness or injury that would prevent completion of the exercise testing protocol.
- Able to complete high-intensity treadmill exercise testing.
- Willing to consume the assigned supplement daily for the full intervention period.
- Willing to avoid probiotic supplements, prebiotic supplements, and other new immune- or gut-health-related supplements during the study period.
- Willing and able to provide saliva samples and complete daily upper respiratory symptom monitoring.
- Able to provide written informed consent.
Who cannot join
- Current acute respiratory, gastrointestinal, or systemic illness at enrolment.
- Use of antibiotics within the previous 4 weeks.
- Regular use of probiotic or prebiotic supplements before enrolment, unless willing to stop before and during the study period.
- Use of medication or supplements likely to affect immune, inflammatory, gastrointestinal, or salivary biomarker outcomes.
- Known chronic gastrointestinal disease, immune disorder, metabolic disease, cardiovascular disease, or other medical condition that could affect study outcomes or exercise safety.
- Known allergy or intolerance to any ingredient in the probiotic or placebo capsule.
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- Current smoker or regular nicotine user.
- Any musculoskeletal injury or health condition limiting maximal or high-intensity treadmill exercise.
- Participation in another intervention study during the study period.
- Inability or unwillingness to comply with the study procedures.
Trial locations and contacts
1 site in 1 country.
United Kingdom1 site
Ulster University Belfast Campus, Human Physiology Laboratory, Room BC-04-409
Belfast, Northern Ireland, BT15 1ED
About this study
Official title: A Randomized, Double-Blind, Placebo-Controlled Study Exploring the Impact of Multi-Strain Probiotic Supplementation on Mucosal Immunity and Upper Respiratory Symptom Episodes in Team-Sport Athletes
This completed external pilot study assessed the feasibility of conducting a randomised, double-blind, placebo-controlled trial of four-week multi-strain probiotic supplementation in trained athletes. Participants were allocated to receive either one probiotic capsule containing 20 billion colony-forming units or a matched rice-flour placebo capsule daily for 28 days. Feasibility measures included recruitment, retention, supplementation adherence and completion of daily monitoring records. Preliminary biological and symptom outcomes included salivary secretory immunoglobulin A and upper respiratory symptom burden. The findings were intended to inform the design of a future definitive randomised controlled trial and were not intended to provide a definitive assessment of efficacy.
Read the detailed description
This study was conducted as a randomised, double-blind, placebo-controlled, parallel-group external pilot trial. Trained athletes were allocated in a 1:1 ratio to a probiotic group or a placebo group for 28 days.
Participants assigned to the probiotic group consumed one Elite Pro 20 Biotic capsule daily. Each capsule provided 20 billion colony-forming units and contained Bifidobacterium lactis Bl-04, Lactobacillus paracasei Lpc-37, Lactobacillus acidophilus NCFM, Bifidobacterium lactis Bi-07 and Bifidobacterium bifidum Bb-02. Participants assigned to the control group consumed one visually matched capsule containing rice flour daily. Participants and investigators remained blinded to treatment allocation during data collection.
Participants completed daily upper respiratory symptom and training-monitoring records throughout the intervention. Saliva samples were collected at baseline and after 28 days, both before and immediately after a standardised treadmill exercise challenge. Salivary secretory immunoglobulin A was assessed as a marker of mucosal immunity.
The principal purpose of this external pilot was to assess study feasibility, including recruitment, retention, supplementation adherence, capsule return and completion of monitoring records. Salivary secretory immunoglobulin A and upper respiratory symptom outcomes were examined to generate preliminary estimates and inform the methods and sample-size planning of a future definitive trial. A conventional efficacy-based sample-size calculation was therefore not undertaken, and the outcome findings were considered exploratory and hypothesis-generating.
- Conditions
- Upper Respiratory Symptoms, Mucosal Immunity
- Being tested
- Multi-Strain Probiotic, Rice Flour Placebo
- Keywords
- Probiotics, Trained Athletes, Salivary Secretory Immunoglobulin A, sIgA, Upper Respiratory Symptoms, Mucosal Immunity, Exercise Immunology, External Pilot Randomized Controlled Trial
- Medical subject headings
- Signs and Symptoms, Respiratory
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Multi-Strain ProbioticDietary supplement
One oral capsule was taken daily for 28 days. Each capsule provided 20 billion colony-forming units and contained Lactobacillus acidophilus NCFM, Lactobacillus paracasei Lpc-37, Bifidobacterium lactis Bl-04, Bifidobacterium lactis Bi-07, and Bifidobacterium bifidum Bb-02
Rice Flour PlaceboDietary supplement
One visually matched oral capsule containing rice flour and no live microorganisms was taken daily for 28 days.
| Study group | Role | What they receive |
|---|---|---|
| Probiotic | Experimental | Participants received one Elite Pro 20 Biotic multi-strain probiotic capsule containing 20 billion CFU once daily for 28 days. Receives: Dietary Supplement: Multi-Strain Probiotic |
| Placebo | Placebo comparator | Participants received one visually matched capsule containing rice flour once daily for 28 days. Receives: Dietary Supplement: Rice Flour Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Resting Salivary Secretory Immunoglobulin A Concentration
Saliva was collected immediately before a standardised treadmill exercise challenge at baseline and after 28 days of supplementation. Secretory immunoglobulin A concentration was measured using an enzyme-linked immunosorbent assay. Day 28 resting sIgA was compared between groups while accounting for baseline resting sIgA.
Measured: Baseline and Day 28
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted24 Aug 2026
- Study start13 May 2025
- Primary completion19 Dec 2025
- Study completion19 Dec 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Upper Respiratory 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
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Participants were randomly assigned in a 1:1 ratio to receive either a multi-strain probiotic capsule or a matched rice-flour placebo capsule once daily for 28 days.
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 15 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Ulster
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Andrea McNeilly, PhD, Principal investigator, Ulster University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07782983
- Sponsor's protocol ID
- REC.24.0071
- Status last verified
- Aug 2026
- First submitted
- 19 Aug 2026
- Last updated
- 24 Aug 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Individual participant data will not be shared publicly or with external researchers. Data will be stored securely in accordance with Ulster University research governance, GDPR requirements, and the approved ethics protocol. Only authorised members of the research team will have access to coded study data. Results will be reported only in anonymised aggregate form in publications and presentations.
Study at a glance
From the registry record, last updated by the sponsor on 24 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Randomized, Double-Blind, Placebo-Controlled Study Exploring the Impact of Multi-Strain Probiotic Supplementation on Mucosal Immunity and Upper Respiratory Symptom Episodes in Team-Sport Athletes
- ClinicalTrials.gov ID
- NCT07782983
- Acronym / sponsor ID
- REC.24.0071
- Conditions
- Upper Respiratory Symptoms, Mucosal Immunity
- Keywords
- Probiotics, Trained Athletes, Salivary Secretory Immunoglobulin A, sIgA, Upper Respiratory Symptoms, Mucosal Immunity, Exercise Immunology, External Pilot Randomized Controlled Trial
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 15 participants (actual)
- Lead sponsor
- University of UlsterUniversity, hospital or other
- Study start
- 13 May 2025 (actual)
- Primary completion
- 19 Dec 2025 (actual)
- Study completion
- 19 Dec 2025 (actual)
- First posted
- 24 Aug 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.
This completed external pilot study assessed the feasibility of conducting a randomised, double-blind, placebo-controlled trial of four-week multi-strain probiotic supplementation in trained athletes. Participants were allocated to receive either one probiotic capsule containing 20 billion colony-forming units or a matched rice-flour placebo capsule daily for 28 days. Feasibility measures included recruitment, retention, supplementation adherence and completion of daily monitoring records. Preliminary biological and symptom outcomes included salivary secretory immunoglobulin A and upper respiratory symptom burden. The findings were intended to inform the design of a future definitive randomised controlled trial and were not intended to provide a definitive assessment of efficacy.
Detailed description
This study was conducted as a randomised, double-blind, placebo-controlled, parallel-group external pilot trial. Trained athletes were allocated in a 1:1 ratio to a probiotic group or a placebo group for 28 days.
Participants assigned to the probiotic group consumed one Elite Pro 20 Biotic capsule daily. Each capsule provided 20 billion colony-forming units and contained Bifidobacterium lactis Bl-04, Lactobacillus paracasei Lpc-37, Lactobacillus acidophilus NCFM, Bifidobacterium lactis Bi-07 and Bifidobacterium bifidum Bb-02. Participants assigned to the control group consumed one visually matched capsule containing rice flour daily. Participants and investigators remained blinded to treatment allocation during data collection.
Participants completed daily upper respiratory symptom and training-monitoring records throughout the intervention. Saliva samples were collected at baseline and after 28 days, both before and immediately after a standardised treadmill exercise challenge. Salivary secretory immunoglobulin A was assessed as a marker of mucosal immunity.
The principal purpose of this external pilot was to assess study feasibility, including recruitment, retention, supplementation adherence, capsule return and completion of monitoring records. Salivary secretory immunoglobulin A and upper respiratory symptom outcomes were examined to generate preliminary estimates and inform the methods and sample-size planning of a future definitive trial. A conventional efficacy-based sample-size calculation was therefore not undertaken, and the outcome findings were considered exploratory and hypothesis-generating.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, investigator)
- Number of arms
- 2
- Model description
- Participants were randomly assigned in a 1:1 ratio to receive either a multi-strain probiotic capsule or a matched rice-flour placebo capsule once daily for 28 days.
| Arm | Type | Receives |
|---|---|---|
| Probiotic | Experimental | Dietary Supplement: Multi-Strain ProbioticParticipants received one Elite Pro 20 Biotic multi-strain probiotic capsule containing 20 billion CFU once daily for 28 days. |
| Placebo | Placebo comparator | Dietary Supplement: Rice Flour PlaceboParticipants received one visually matched capsule containing rice flour once daily for 28 days. |
Who may qualify
- Ages
- 18 to 40 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (8 listed)
- Male trained athletes aged 18-40 years.
- Regularly participating in structured training and/or competitive sport.
- Apparently healthy at enrolment, with no acute illness or injury that would prevent completion of the exercise testing protocol.
- Able to complete high-intensity treadmill exercise testing.
- Willing to consume the assigned supplement daily for the full intervention period.
Key exclusion criteria (10 listed)
- Current acute respiratory, gastrointestinal, or systemic illness at enrolment.
- Use of antibiotics within the previous 4 weeks.
- Regular use of probiotic or prebiotic supplements before enrolment, unless willing to stop before and during the study period.
- Use of medication or supplements likely to affect immune, inflammatory, gastrointestinal, or salivary biomarker outcomes.
- Known chronic gastrointestinal disease, immune disorder, metabolic disease, cardiovascular disease, or other medical condition that could affect study outcomes or exercise safety.
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 |
|---|---|---|
| Multi-Strain ProbioticOne oral capsule was taken daily for 28 days. Each capsule provided 20 billion colony-forming units and contained Lactobacillus acidophilus NCFM, Lactobacillus paracasei Lpc-37, Bifidobacterium lactis Bl-04, Bifidobacterium lactis Bi-07, and Bifidobacterium bifidum Bb-02 | Dietary supplement | Probiotic |
| Rice Flour PlaceboOne visually matched oral capsule containing rice flour and no live microorganisms was taken daily for 28 days. | Dietary supplement | Placebo |
Primary outcome
Resting Salivary Secretory Immunoglobulin A Concentration
Time frame: Baseline and Day 28
Saliva was collected immediately before a standardised treadmill exercise challenge at baseline and after 28 days of supplementation. Secretory immunoglobulin A concentration was measured using an enzyme-linked immunosorbent assay. Day 28 resting sIgA was compared between groups while accounting for baseline resting sIgA.
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 24 Aug 2026.
- Individual participant dataSharing planned: No. Individual participant data will not be shared publicly or with external researchers. Data will be stored securely in accordance with Ulster University research governance, GDPR requirements, and the approved ethics protocol. Only authorised members of the research team will have access to coded study data. Results will be reported only in anonymised aggregate form in publications and presentations.
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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.
Andrea McNeilly, PhD principal investigator
Ulster University
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Multi-Strain Probiotic in people with Upper Respiratory Symptoms and Mucosal Immunity, run by University of Ulster at 1 site in United Kingdom.
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 8 inclusion and 10 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 24 Aug 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 Kingdom. 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?
Resting Salivary Secretory Immunoglobulin A Concentration (time frame: Baseline and Day 28). 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 24 Aug 2026.