The Effects of Postbiotic Supplementation in Female Athletes

NCT07580118 | Not Yet Recruiting

• 1 other identifier: 25/SPS/057_2026
• Study Type: interventional
• Target: 100
• Locations: 1 country
• Sites: 1

Brief Summary

The goal of this clinical trial is to learn if a postbiotic supplement can reduce stomach and gut symptoms in physically active women. The main questions it aims to answer are: Does the supplement reduce gut symptoms during the menstrual cycle? Does it improve symptoms related to exercise? Researchers will compare the postbiotic supplement to a placebo (a look-alike capsule that contains no active ingredient) to see if the supplement works. Participants will be physically active, premenopausal female athletes. Participants will: Take either the postbiotic supplement or a placebo each day for two menstrual cycles Track their menstrual cycle and training Report gut symptoms using regular questionnaires Provide stool samples to assess gut health This study will help researchers understand whether postbiotic supplements can improve gut health and reduce symptoms that may affect training and performance in female athletes.

Conditions

Gastrointestinal Symptoms; Menstrual Cycle

Outcome Measures

Primary Outcomes (1)

• Gastrointestinal Symptom Severity During Menstruation

  To assess the effect of daily consumption of Humiome® Post LB (HPLB) on menstrual cycle-related gastrointestinal symptoms (total amended Gastrointestinal Symptom Rating Scale scores; aGSRS) during the final intervention menstrual cycle (Phase 3) in physically active, premenopausal female athletes.

  At the post menstruation assessment following completion of cycle 4 ~84-147 days depending on individual cycle and menstruation duration

Secondary Outcomes (11)

• Total Gastrointestinal Symptom Rating Scale (GSRS) score assessed weekly across the two intervention menstrual cycles.

  Weekly from the start of Cycle 2 through completion of Cycle 4 (up to 147 days from baseline; cycles range 21-35 days

• Total Gastrointestinal Symptom Rating Scale Score

  Weekly from the start of the start of the first intervention cycle (Cycle 2) through completion of the final intervention cycle (Cycle 4), up to 147 days from baseline

• GSRS Sub-Category Scores

  Weekly from the start of the start of the first intervention cycle (Cycle 2) through completion of the final intervention cycle (Cycle 4), up to 147 days from baseline

• Wilson Gastrointestinal Symptom Score

  Daily during menstruation on Day 1 (±1 day) of Cycle 2 (phase 2), Cycle 3 and Cycle 4 (phase 3). Up to 147 days from baseline.

• Faecal microbial composition

  Menstruation on Day 1 (±1 day) of Cycle 2 (phase 2) and Cycle 4 (phase 3). Approximately 28-140 days from baseline depending on individual menstrual cycle duration.

Study Arms (2)

Postbiotic Supplementation

EXPERIMENTAL

All participants complete a one menstrual cycle placebo run-in phase before randomisation. Participants in this arm then receive the postbiotic supplement daily for two consecutive menstrual cycles.

Dietary Supplement: Postbiotic; Dietary Supplement: Placebo

Placebo

PLACEBO COMPARATOR

All participants complete a one menstrual cycle placebo run-in phase before randomisation. Participants in this arm then continue taking placebo daily for two consecutive menstrual cycles.

Dietary Supplement: Placebo

Interventions

Postbiotic DIETARY_SUPPLEMENT

Postbiotic supplement (Humiome® Post LB) administered as two oral capsules daily, providing 340 mg of postbiotic per day. The supplement contains heat-inactivated microbial strains and fermentation products. Participants will take the supplement daily for two consecutive menstrual cycles following a one-cycle placebo run-in phase.

Postbiotic Supplementation

Placebo DIETARY_SUPPLEMENT

Placebo capsules containing microcrystalline cellulose, matched in appearance to the postbiotic supplement. Participants will take two capsules daily during a one-cycle placebo run-in phase and, if randomized to the placebo group, continue for two additional menstrual cycles.

Placebo; Postbiotic Supplementation

Eligibility Criteria

• Age: 18 Years+
• Gender Eligibility Details: Participants must be individuals who identify as female, are premenopausal, and have regular menstrual cycles.
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Female, cisgender, premenopausal.
• Minimum age 18 years.
• Regular, natural menstrual cycle (21-35 days in duration), with 9 or more consecutive periods per year, if possible documented with tracker apps, calendars, or other tools
• Ability to give informed consent.
• Body mass index (BMI) ≥ 18.5 and \< 24.9 kg/m²
• Agreeing to maintain lifestyle habits during the study (same dietary and physical activity habits)
• Having a smartphone and a history of consistent tracking of training and health records via apps.
• Having regular GI issues during exercise, and during menstruation. During pre-screening, this will be assessed with a shortened GSRS questionnaire, where participants need to have had, in the month preceding pre-screening, the equivalent of at least a score of 2 in a GSRS focus area (diarrhoea, pain, indigestion).
• No relevant self-reported abnormalities from medical history.
• Trained athlete (trains at least 3 times per week for more than 1 hour per day and who has been involved in endurance training for at least 2 years in alignment with previous research (Pfeiffer et al., 2010). This will be evaluated by assessing training records (Strava or similar applications, certificates of attendance at athletic events, club membership, etc.).
• Access to a health-care provider, who can be contacted by the CRO, and who reside in areas with available emergency health services.

You may not qualify if:

• Individuals who are pregnant, lactating, or plan to become pregnant before study end.
• Individuals with secondary amenorrhea.
• Individuals who use hormonal contraceptives during the last 6 months before (and during) the trial.
• Individuals who are currently participating in another clinical trial or have participated in a trial within the last two months prior to enrolment.
• Tobacco smokers and vapers.
• Individuals with acute illnesses.
• Individuals with a current musculoskeletal injury or one within the last month.
• Individuals taking probiotic supplements or have taken probiotics two weeks prior to enrolment.
• Individuals controlling chronic diseases with treatments known to alter the intestinal microbiome or to alter GI symptoms, such as certain pain killers, antacids, proton pump inhibitors, anti-diarrhoeal medication or supplements, and laxatives.
• Individuals having received antibiotics treatments within three months of trial start.
• Individuals having planned major changes in lifestyle (i.e. diet, weight loss program, exercise level, travelling) during the duration of the study.
• Individuals who have hypersensitivity/allergy to any of the components of the test product.
• Individuals who have planned major elective surgery during the study period.

Sponsors & Collaborators

• Liverpool John Moores University: lead

Study Sites (1)

Tom Reilley Building

Liverpool, Merseyside, L3 3AF, United Kingdom

Location

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Study Officials

• Kelsie Johnson, PhD

  Liverpool John Moores University

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Kelsie Johnson, PhD

CONTACT

+44 0151 231 2121; k.o.johnson@ljmu.ac.uk

Samantha Moss, PhD

CONTACT

0151 231 2121; S.L.Moss@ljmu.ac.uk

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: TRIPLE
• Who Masked: PARTICIPANT, INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Senior Lecturer in Sports Nutrition and Physiology

Model Details: All participants will complete an initial placebo run-in phase lasting one menstrual cycle. Following this, participants will be randomly assigned to receive either the postbiotic supplement or continue with placebo for two additional menstrual cycles. Outcomes will be compared between groups to assess the effect of the intervention on gastrointestinal symptoms.

Study Record Dates

• First Submitted: April 22, 2026
• First Posted: May 12, 2026
• Study Start: May 5, 2026
• Primary Completion (Estimated): March 30, 2027
• Study Completion (Estimated): May 30, 2027
• Last Updated: May 12, 2026

Record last verified: 2026-04

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, CSR
• Time Frame: Data will be available following publication for a period of up to 5 years.
• Access Criteria: Data will be available to researchers who provide a methodologically sound proposal, subject to approval by the principal investigator. Requests should be directed to the principal investigator.

Locations

GB (1)