Can probiotics improve your performance?

We at FitBiomics think so, but as scientists, we want to make sure that we have evidence to show this is the case. While randomized controlled studies (where some participants receive the real drug and others get a placebo) are the gold standard for answering these types of questions, to accelerate research in a cost-effective manner, we offered our probiotics to consumers to beta test in exchange for weekly surveys on how they thought the probiotics were affecting different aspects of their health and wellbeing. This approach allows us to quickly develop hypotheses, which we can then test with more scientifically robust clinical studies and detailed mechanistic lab tests. From this, our first beta-test, we learned that most participants experienced wide-ranging benefits that could lead to improved athletic performance.

The probiotics used in this beta test, and now available in Nella by FitBiomics, were isolated from the guts of elite athletes that compete at the highest levels. These probiotic bacteria were grown, processed, and encapsulated by companies with extensive experience creating safe and effective live probiotics. Each participant was mailed a two-week supply of probiotics in one of two doses: a low dose and a high dose. Participants provided information on their health and well-being using online surveys before taking the probiotics, after 1 week, and after 2 weeks of taking the probiotics every day. Though probiotics were mailed to more than 1,000 participants, this analysis focuses on the 257 who successfully filled out the survey questions every week (Figure 1).

Figure 1: The FitBiomics beta-testing process allows us to quickly understand how probiotics affect performance


Step 1: Probiotic bacteria were isolated from elite athletes and manufactured into probiotics. Step 2: Probiotics were sent to more than 1,000 participants. Each participant received a low or high dose. Step 3: Participants filled out weekly surveys on the effect of the probiotics. 257 completed all weekly surveys. Step 4: Once all the surveys were completed, Fitbiomics analyzed the data including using machine learning strategies to better understand how the probiotics affected the beta-testers and inform next-generation products. 

Were there any benefits to taking these probiotics?

Yes, there were! In the surveys, we asked questions about digestion, energy, sleep, recovery, workouts, overall health, and experience taking the probiotics. We found that about 20-40% of participants reported improvements in each of these categories, and 94% reported improvements in at least one of the categories (Figure 2). Some of the largest changes were seen in improved sleep quality, decreased soreness after workouts, shorter recovery time after an intense workout, and better / more regular bowel movements.

Figure 2: Probiotic use was associated with improvements that could lead to improved athletic performance
94% of participants saw benefits in at least one of the categories. Some of the largest changes were seen with sleep quality (45% reported improvements), recovery time (38.5% had a shorter recovery time after an intense workout), fatigue frequency (38.3% had less fatigue), soreness after workouts (38% were less sore than expected), and bowel movements (34.6% had better and more regular bowel movements after taking the probiotic).

Who had the best overall experience?

When asked about overall experience, 74% claimed to have an overall positive experience taking these probiotics, but we wanted to better understand what types of people were more likely to experience a benefit. This is important because everyone’s gut is different. Everyone has a slightly different community of bacteria living in their intestines and an immune system that interacts with probiotics in slightly different ways. Therefore, we might expect that a probiotic that works wonders for most people might cause minor GI distress for others.

To answer this question, we turned to machine learning. Machine learning is used across our lives to classify people and predict their behavior. In the same way that Netflix takes data on what customers watch and builds a model to predict who might like period romances vs action movies, we used data from the surveys to create a machine learning model that classified participants into those that enjoyed the beta-test experience, those that were indifferent, and those that had a negative experience. Then, we looked to see what characteristics predicted that they would have a positive vs negative reaction to the probiotics. It turns out that there were no specific demographics characteristics (age, gender, race, income, etc.) that predicted a positive response to probiotic use. This is interesting because it means that there isn’t one type of gut microbiome community associated with any one of these demographic categories. The characteristics that drive a positive response are more subtle. We did find that those that enjoyed using these probiotics were also those that reported generally improved health/fitness, better bowel movements, increased energy, and fewer days with fatigue, which agrees with the findings of the first part of our first analysis.

Were there any differences between the high and low dose?

One of the most important questions to understand when developing any kind of new therapy is figuring out the right dose. Here, we looked at benefits and side effects associated with a high dose vs a low dose. In terms of overall experience, there was no real difference between those that received the low dose and the high dose. This isn’t too surprising because even our low dose had more viable bacteria in it than most probiotics available in the market. It was good to see that even those that got the lower dose were experiencing benefits, providing more evidence of the quality of Nella. Similarly, we didn’t see any major differences in side effects between those that got the low and high doses, with two exceptions. Constipation was much more common in those that got the low dose, and fatigue was more common in those that got the higher dose. The constipation is likely a side effect of the GI tract getting used to the probiotics, and if we had tracked the participants longer, we expect it would have normalized. However, the cause of the fatigue is more mysterious. It was a rare side effect even at the high dose, but to be on the safe side, the dose in Nella is lower than the high dose tested here.

What’s next?

This thorough analysis helped us understand a lot about Nella, and we are very excited to see that the vast majority of our beta-testers reported benefits that could lead to better performance. Those that enjoyed the beta test tended to see benefits across the health spectrum, from improved bowel movements to quicker recovery. This is especially remarkable because these results were seen after only 2 weeks of probiotic use! Furthermore, this analysis provides a template for assessing the next generation of FitBiomics probiotics. Of course, in science, exciting results just lead to more questions. How much more benefit will we see with long-term use? How are these probiotics improving performance? Can we predict who is most likely to experience side effects? We hope to answer these questions soon with more controlled studies, where we will also collect stool and blood samples to increase our understanding of how probiotics impact performance. This way, FitBiomics can continuously improve our products for you!


WRITTEN BY:  Marina Santiago, PhD



Dr. Santiago has a Ph.D. in Chemical Biology from the Microbiology and Immunobiology Department of Harvard Medical School, but she has been fascinated by microbes and microbial communities for as long as she can remember. She works as an independent R&D strategy consultant and helps companies create and use evidence-based frameworks for making strategy decisions as well as helping them launch new programs or initiatives. Dr. Santiago is also passionate about fitness and the outdoors. In her free time, she enjoys running, hiking, and backpacking very long distances, as well as slowly getting better at yoga, Muay Thai, and Jiu Jitsu. 

Dr. Santiago knows first hand how improving gut health can bring your trail running performance to new heights.  Here she is doing her favorite sport - hiking!