Scientists uncover how targeted probiotics may help athletes go further, recover faster, and stay healthier, if the right strains are chosen and research gaps are closed.
Review: Probiotic supplementation for optimizing athletic performance: current evidence and future perspectives for microbiome-based strategies
In a recent review published in the journal Frontiers in Nutrition, researchers collate and synthesize up-to-date scientific knowledge to elucidate relationships and interdependencies between probiotics, the gut microbiome, and athlete exercise performance. The review aims to utilize this information to enable athletes, their trainers, and medical professionals to make informed decisions about training techniques that optimize performance while minimizing adverse physiological effects.
The review highlights the multifaceted potential benefits of probiotic supplementation in athletes, including modulation of inflammation, improvement in gut barrier function, and evidence of altered metabolic pathways. However, it cautions that the effects are highly strain-specific, dose-dependent, and dependent on the type of sport, and that not all studies show positive results. It suggests that incorporating probiotic supplementation in athletic training plans may be beneficial for some athletes, but further research is needed before making universal recommendations.
There is currently insufficient evidence to conclude that probiotic supplementation is essential for preventing injury or that it will consistently provide tangible performance benefits. Current research is highly strain-specific and context-dependent, underscoring the need for standardized and generalizable research, especially for resistance-based sports.
Background
Professional elite sports are attempts at marginal gains, where athletes seek any means of enhancing performance and recovery. Decades of research have established training and nutrition as cornerstones of athletic development. Surprisingly, a key component of physiological well-being (and, by extension, recovery and performance), the trillions of microbes that comprise the gut microbiome, remains largely ignored in most conventional training regimes.
The gut microbiome is a complex ecosystem that actively contributes to nutrient absorption, immune function, and the regulation of inflammation, all of which are critical factors in athletic success. Consequently, a growing body of research in nutrition and sports seeks to unravel the bidirectional associations between gut microbiome properties and athletic health outcomes.
Specifically, this research aims to utilize probiotic supplements to alleviate common athlete complaints (e.g., gastrointestinal distress in endurance runners or upper respiratory tract infections that can compromise performance) and enhance overall performance.
About the review
The present review aims to systematically evaluate the current scientific landscape, revealing the pros and cons of specific probiotic strains, the current limitations of athlete-focused probiotic research, and cutting-edge ongoing research that may enable athletes to push harder with reduced injury risk than ever before.
Peer-reviewed publications investigating “probiotics,” “microbiome,” and “exercise performance” between 2015 and 2024 were identified through a custom keyword search of PubMed and Scopus databases. All identified publications were subjected to title, abstract, and full-text screening, with both animal and human trials included in review outcomes.
Review outcomes were classified into three categories to improve recommendation specificity: 1. Endurance-based sports, 2. Intermittent-exercise sports, and 3. Resistance training. For each category, the review synthesizes a clear overview of what is known, what is promising, and where critical gaps in our knowledge remain. The review also discusses a fourth group, wheelchair athletes, as an understudied population regarding probiotic supplementation.
Review findings
Endurance athletes
This subcategory of athletes (runners, cyclists) is the best studied from the gut microbiome lens. The review reveals that exercise-induced gastrointestinal distress is the most common physiological concern among endurance athletes. Encouragingly, several studies leveraging multi-strain probiotic supplements have reported significant decreases in GI symptoms following supplementation.
Specific probiotic strains have been further linked to direct performance enhancement. For example, supplementation with Bifidobacterium lactis BL-99 in cross-country skiers improved lipid metabolism and VO₂ max. Similarly, a 16-week study on road cyclists using a multi-strain formula reported improved aerobic capacity and time to exhaustion in some measures, while other studies found no significant effects on VO₂ max or time to fatigue.
Mechanistic evaluations attribute these observed benefits to reduced systemic inflammation (lower levels of pro-inflammatory cytokines like TNF-α and IL-6) and mitigated oxidative stress. However, not all studies have demonstrated positive effects, and some have shown no significant changes in key performance outcomes. Additionally, the review discusses mechanistic pathways, such as the gut–liver axis and gut–brain axis, which may mediate some of the observed physiological effects.
Importantly, a 6-week intervention in football players using a synbiotic (probiotic + prebiotic) was associated with a boosted maximal heart rate (HRmax) and lactic acid elimination rate compared to controls; however, an increase in HRmax is physiologically counterintuitive for improved recovery and may reflect limitations in the source paper’s interpretation or reporting.
Intermittent-exercise athletes
While not as extensively studied as endurance athletes, intermittent-exercise athletes (e.g., soccer and basketball) also demonstrate benefits from probiotic supplementation. Notably, probiotics significantly reduce the incidence and duration of upper respiratory tract infections, thereby mitigating instances of missed training and competition. A 6-week intervention in football players using a synbiotic markedly lowered URTI symptoms while boosting HRmax and lactic acid elimination rate compared to controls.
Several studies have demonstrated the mental health and mood-enhancing benefits of probiotic supplementation. A 6-week Lactobacillus casei intervention resulted in lower stress and anxiety levels in badminton players, while also improving metrics of their aerobic capacity. However, other trials in dancers and soccer players did not observe significant effects on pain, fatigue, or certain performance metrics, highlighting variability in findings.
Resistance athletes
In contrast to endurance and intermittent-exercise athletes, resistance athletes (e.g., bodybuilders) remain significantly under-researched. Limited data suggest that probiotic supplementation with Bacillus coagulans can enhance branched-chain amino acid absorption and improve leg press power in trained males, indicating potential benefits across physiology and performance. Other studies in resistance-trained athletes report improvements in certain strength measures and body composition; however, the results are inconsistent, and the data are sparse. Factors such as probiotic dosage, duration, and frequency of supplementation may influence outcomes and require further study.
Wheelchair athletes
Wheelchair athletes represent an understudied population with unique challenges. Limited evidence suggests that probiotic supplementation may reduce inflammatory markers and improve gut microbiome diversity; however, the findings are mixed, with some studies showing reduced inflammation but no significant improvement in gastrointestinal symptoms.
Conclusions
Probiotic supplementation is a promising but nuanced strategy for athletes. The review emphasizes that a one-size-fits-all approach is ineffective, with benefits being highly strain-specific, dose-dependent, and tied to the demands of the sport. While endurance and intermittent-sport athletes can gain measurable advantages in gut health, immunity, and aerobic performance, current data are insufficient for those in strength and power sports.
Some studies report no significant improvements in key performance or health measures, underlining the need for further robust, standardized research to establish the efficacy of probiotics in sports settings. Future studies should explicitly document supplementation protocols and clarify mechanistic pathways such as gut–brain and gut–liver axis modulation.
Future research should standardize methodologies, focus on specific strains, and elucidate the precise mechanisms (e.g., neurotransmitter production) of probiotic interactions, enabling evidence-based sports plans. At present, probiotic supplementation shows promise but should not be considered a guaranteed or universal strategy for optimizing athletic performance until more conclusive evidence is available.