What to Look for in a Probiotic Supplement

by Amylee Amos MS, RDN, IFMCPLifestyle
Open palm holding three capsules

What are Probiotic Supplements?

Probiotics are live microorganisms (generally bacteria and yeast) that are taken for an intended health benefit, usually the health of the gut microbiome. The gut microbiome plays a major role in both our physical and psychological health, so keeping it in optimal condition is a powerful strategy for maintaining overall health. Probiotics can be broken down into foodborne microbes, such as those that exist in the soil and on produce as well as those used in the fermentation process, and microbes in supplement form. Both of these have an impact on the gut microbiome. However, the vast majority of research of probiotics has been conducted with probiotic supplements.

Because a large body of evidence suggests that probiotic supplements may be beneficial, this class of supplements has become exceedingly popular. Countless probiotic supplements are on the market, making choosing a probiotic supplement challenging. Probiotic supplements vary significantly from one product to another. Supplements vary in the sourcing of the strains, the preparation of the strains, the strains themselves, and the amount of colony forming units contained in the supplement. Each of these factors influence the effect of the probiotic supplement in regards to its influence on gut health. 

What Strains of Probiotics Are Best?

The best strain of probiotics depends on your reason for taking a probiotic supplement in the first place. Some strains have been studied and found to be efficacious for specific disease states. The best type of probiotic for general gut health is a multi-strain probiotic that has five or more probiotic strains including at least two Lactobacilli and two Bifidobacterium strains. A product with Streptococci and Saccharomyces boulardii is even more beneficial. 

While it appears from the existing literature that these strains will benefit general gut microbial health and prevent dysbiosis, it should be noted that large clinical trials that investigate the efficacy of one probiotic strain compared to another are currently lacking. Thus, this multi-strain approach seems to be the most likely to confer the most benefit. 

What is the Right Dose of Probiotics?

Probiotic supplements are measured in colony forming units (CFU). For the purpose of general gut health, a dose of 20-40 billion CFU seems to be sufficient and safe for healthy adults. Higher doses have been studied in specific disease states and should only be taken under the guidance of a healthcare practitioner. As discussed regarding the specific strains of probiotics, research comparing different doses of probiotics is currently lacking. 

Do Probiotic Supplements Need to Be Refrigerated?

Probiotics are highly prone to degradation. Choosing a supplement that is manufactured without strict procedures regarding temperature control can result in a product with no viable probiotic strains- and thus, no benefit! 

Probiotic supplements have a limited shelf life. For this reason, we recommend choosing a probiotic supplement that has a listed expiration date and taking it within that time frame. Most probiotics have a relatively long room temperature shelf life. Most probiotic supplements do not require refrigeration. In fact, once a probiotic supplement container has been opened, refrigerating the product can expose it to excess moisture which diminishes shelf life. 

What is important is the regulation of the temperature before you receive it. High quality probiotic supplements that you order from reputable companies will arrive in insulated containers with cold packs to ensure that the product was not exposed to high temperatures in transit. 

When Should I Take My Probiotic Supplement?

The best time to take a probiotic supplement is relatively unresearched. Most studies on probiotics don’t even mention timing of administration in the description of the study methods. This suggests that timing of taking probiotics is likely uncontrolled for, and could be a factor leading to conflicting concluding results. 

The best time to take your probiotic supplement is whenever is most convenient for you. Doing this will make it more likely that you actually take your probiotic supplement. Since the research regarding whether taking probiotic supplements at a specific time of day and with or without food is lacking and insubstantial, at this time making such a recommendation is not evidence based. 

Despite the massive popularity of probiotic supplements, research into the best type of probiotic to take, the optimal dose, and the right time to take it is lacking. Studies generally don’t compare different types of probiotic supplements with one another. Rather in most studies, a specific probiotic supplement is compared against a placebo. This makes drawing conclusions as to the best probiotic qualities challenging, leaving us to rely on educated inferences rather than finite data. 

That being said, certain probiotic supplements are certainly superior to others based on what we know of beneficial strains and the quality control of the manufacturer. At the Amos Institute, we have curated a list of all of our favorite supplements for cognitive health, which includes a high quality probiotic supplement. You can access our list of favorite products, along with other high quality supplements for 10% off MSRP through our Fullscript account


  1. Sanders ME. doi: 10.1086/523341.
  2. Derrien M, et al. doi: 10.1016/j.tim.2015.03.002. 
  3. Hütt P, et al. doi: 10.3920/BM2010.0023
  4. Guilliams, T.G. (2016). ISBN: 978-0-9856158-3-3