Episode 148 – Can Probiotics Improve Athletic Performance?

Key Topics Covered


  • It’s unusual to expect probiotics to have a significant impact on performance, however since the gut microbiome is linked to a range of outcomes, this is a topic worth exploring.
  • The ‘chicken or the egg’ scenario is fairly relevant though e.g. when you look at the gut microbiome of elite athletes, it is very different to regular peoples. But exercise also influences gut-health too.
  • It could influence performance directly through improving actual performance outcomes OR it could influence it indirectly, by reducing the risk of things that could be negatives for performance, such as illness or gut symptoms.

Overall Research

  • A 2023 systematic review of all the RCTs looking at probiotics and performance found 13 relevant studies and 11 of the 13 found positive benefits, albeit not all of them were statistically significant.
  • There are still so many gaps in the research. One big example of this is that each study just uses an individual strain. Most products have multiple strains. 


  • While the link might not seem definitive at first glance – there are a number of mechanisms as to how probiotics could reduce upper respiratory tract infections. 
  • Some relevant functions of probiotics include:
  1. They can play a role in the immune system and stimulate the production and activation of certain antibodies.
  2. They can also strengthen the barrier of the mucosal lining, making things difficult for pathogens to get through.
  3. They inhibit the growth of harmful bacteria.
  4. And They could reduce inflammation – and that inflammation plays a role in the symptoms of upper respiratory tract infections.


  • A 2022 systematic review found 16 relevant studies and the majority found improvements in either the reduction in risk of getting sick, or reduced duration or severity of illness.
  • These aren’t huge improvements, but they are relevant.
  • Less days sick can equate to more days training/competing at full abilities.

Gut Symptoms

Probiotics under microscope.

  • It is well established that probiotics can help IBS-type symptoms.
  • This could obviously have huge applications for ultra-endurance sports if it is helpful.
  • It’s not a huge or consistent benefit though. See the blog post linked below for more detail.
  • Around 10 RCTs have been done on this topic. Unlike other areas, there is more consistency in methodology, with at least 7 studies using a Lactobacillus and Bifidobacterium multi-strain approach.
  • The short version is that only slight evidence has been found for improvements in GI symptoms in athletes during training and competition.
  • Overall, more studies are needed. 

Recovery & Inflammation

  • A 2021 RCT found  less muscle soreness vs placebo, lower CRP (crp is a protein which is found in higher amounts in the body when inflammation is high) and improved sleep.
  • This was in a group of elite rugby players over 17 weeks of competition. The probiotic was ultrabiotic 60 and they also used Saccharomyces boulardii. 
  • Other studies have also found small reductions in oxidative stress and reduced inflammation markers.
  • Personally we are not at a point where we’d recommend it for those purposes. But it’s still an interesting area of research.

Strength & Endurance

Man with barbell pre deadlift.

  • Some research in endurance athletes has found improvements in performance as measured by aspects like time trials and time to exhaustion.
  • No differences in body composition or VO2 max have been found though.
  • Research looking at strength has found inconsistent improvements.
  • Most of the performance research is on endurance athletes, but there still isn’t much. 
  • This is another area where I think it’s too early to be excited, but it’s still worth watching.

Practical Advice

  • There’s not as many clear cut links as we’d like. 
  • But the research does show some promise in a lot of areas.
  • I’d be more likely to use probiotics for specific cases: Example if an athlete is travelling for an international competition, their odds of getting sick and/or experiencing gut symptoms is higher, so adding in a probiotic makes sense.
  • In general, Most people should have a prebiotic rich diet and also include some probiotics in their diet.

Which Probiotic Strain to Take

Probiotic strains.

  • We have a blog post going through how to pick the right probiotic for you, which is listed below. It’s not specific to athletes, but it is still relevant.
  • An overly simplified perspective I personally have is that it makes sense to choose a reputable brand that has a multi-strain formula that is targeted for your specific concern.
  • Since there is so little research looking at multi-strain approaches, it’s hard to say what is a “good” probiotic. A “bad” one would either contain insufficient amounts, or wouldn’t include any strains that have been linked with the benefits you are looking for – but I personally haven’t seen that in many products from reputable companies. 

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