Research
Mixed
Probiotic supplementation does not consistently improve athletic performance metrics (e.g., VO2 max, peak power) across all strains and populations.
Do not take probiotics expecting a direct boost in speed or strength. The evidence for performance enhancement is mixed and strain-specific. Focus on strains with validated health benefits (e.g., immune support) instead.
ModerateQualifiesMEDIUM confidence
Of the 24 studies that assessed some metric of athletic performance, 17 reported a null effect, while 7 reported significant improvement.
Why this rating
Mixed results in human studies.
Source
International Society of Sports Nutrition Position Stand: Probiotics
Ralf Jäger et al. · Journal of the International Society of Sports Nutrition · 2019
DOI 10.1186/s12970-019-0329-0
narrative_reviewCited 258×
Read the paper DOI resolved against Crossref · corpus check 2026-06-10
More from this paper
- Specific probiotic strains reduce the frequency, severity, and duration of upper respiratory tract infections (URTI) in athletes, particularly under conditions of high training load or environmental stress.Good
- Athletes have distinct gut microbiota compositions compared to sedentary individuals, characterized by higher diversity and abundance of health-promoting bacteria, influenced by exercise and protein intake.Good
- Specific probiotic strains improve gut barrier integrity, reducing gut permeability and systemic endotoxemia caused by intense, prolonged exercise.Moderate
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