Clinical Research Directory

Inclusion Criteria: * 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. Exclusion Criteria: * 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. * 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.