The association between fatigue and probiotics is not straightforward. Scientific literature contains conflicting results. However, what is clear in the science is that the kinds of bacteria in the gut of people suffering from chronic fatigue syndrome are not balanced and that this plays are role in the disease. Although all of the potential causes for chronic fatigue syndrome are not known, a link has been established between this disease and conditions where a population of “bad bacteria” has over taken the normal population of “good bacteria”.
A 2009 pilot study of a small number of people assessed the consequences of giving probiotics to people suffering from chronic fatigue syndrome. It found that 6 out of 15 people noted that probiotics helped them reduce some of the symptoms associated with chronic fatigue such as reduced neurocognitive function. However, none of the study participants noted improvement in fatigue levels. Even so, the researchers performing the study suggested that while more studies are needed, probiotics can be a powerful tool to treat the symptoms of chronic fatigue with the caveat that actual outcomes of consuming probiotics may be greatly dependent on individual people .
Other studies have found links to improvement of fatigue symptoms and probiotics however. Another larger pilot study found that chronic fatigue syndrome patients found a significant decrease in chronic fatigue related anxiety among those patients that took a probotic containing Lactobacillus casei . A recent 2014 study of cancer survivors found improved quality of life, including fatigue, when probiotics where included in their diets . Based on a systematic review of scientific literature, it appears that probiotics can help athletes recover faster from physical activity related fatigue. .
It isn’t clear yet why the effects of probiotics on fatigue vary between people. It is most likely due to the fact that each person’s gut contains a somewhat unique blend of bacteria and other microorganisms. In addition, the various bacteria may release different substances that could interact differently according to what the situation is within each persons gut. This means that each person needs to find a good probiotic to restore the proper balance within their own gut. Since everyone is different, one probiotic might work effectively for you, but not so well for me. The opposite might be true as well. Therefore, if one probiotic doesn’t seem to work, then you need to find a different probiotic.
A good place to start is with a high quality multiple strain probiotic with high strength (or many colony-forming units often abbreviated as CFU’s). It can be hard to find these at your local drug store or on TV; many of these only contain one or two strains or don’t contain a high number of colony-forming units. A good multi-strain probiotic supplement will contain 10, 15, or even 20 different strains and 15 billion or more CFU’s. Hyperbiotics PRO-15 is one such high-strength multi-strain supplement that contains strains similar to those in the studies above such as Lactobacillus casei. Regardless of the multi-strain supplement you choose, don’t hesitate to try a different brand if the one you are using isn’t as effective for you.
 Sullivan, Nord, Evegard; Effect of supplement with lactic-acid producing bacteria on fatigue and physical activity in patients with chronic fatigue syndrome; Nutr J. 2009 Jan 26; 8:4.  Rao, Bested, Bewaune, Katzman, Iorio, Berardi, Logan; A randomized, double-bind, placebo-controlled pilot study of a probiotic in emotional symptoms of chronic fatigue syndrome; Gut Pathog. 2009; 1: 6.  Lee, Chu, Jeon, Lee, Park, Lee, and Kim; Effects of 12 weeks of probiotic supplementation on quality of life in colorectal cancer survivors: A double-blind, randomized, placebo-controlled trial; Dig Liver Dis. 2014 Dec;46(12):1126-32.  Nichols; Probiotics and athletic performance: a systematic review; Curr Sports Med Rep. 2007 Jul;6(4):269-73.