For Whom Are Probiotic Supplements Most Effective?

For Whom Are Probiotic Supplements Most Effective?

Published on Tuesday, January 03, 2023 by Andy De Santis

Probiotic supplements contain various types of microorganisms, often bacteria, that are ingested with the intention of an improvement to one’s health.

The key word there is “intention”. 

Probiotics are among the most utilized supplements in the USA but whether or not a probiotic supplement will meaningfully impact your health and gut microbiome depends on a number of factors including:

  1. The type of probiotic used 
  2. The issue/state you are trying to resolve 
  3. Whether or not it was used properly (ie; duration, consistency)

For example, if you read my previous pieces on probiotic supplementation for PCOS or Fatty Liver, or even for Infant Colic, you’ll notice that certain probiotic strains are used for certain durations to achieve certain outcomes.

And while the sentiment I’ve expressed above is 100% true and very important to acknowledge, it’s actually not the focal point of today’s post.

Allow me to explain.

While PCOS, Fatty Liver Disease, and Infant Colic are three unique conditions they are actually bound together conceptually by the fact they all start with individuals who are suspected to have a disrupted gut microbiome (ie: dysbiosis) at baseline.

According to the work of Dr. Lynne V McFarland, this represents one of three broad categories of individuals who are candidates to utilize probiotic supplements. 

What Dr. McFarland did in her intriguing 2014 BMJ paper is review the general effectiveness of probiotics in achieving their desired outcome across three broad populations in multiple studies.

Let’s take a closer look:

#1 Restoration Demographic

Individuals in the “restoration” demographic generally start with a balanced microbiome, have that microbiome disrupted by an external event (such as antibiotic use) and use probiotic supplements to help restore their microbiome to baseline.

McFarland found that 83% of the studies that fit this criterion demonstrated that probiotic use was effective to achieve its goal.

This makes sense to me intuitively, having for example seen a large body of evidence supporting the strategic use of specific probiotic strains in mitigating Antibiotic Associated Diarrhea (AD). 

#2  Alteration Demographic

Individuals in the “alteration” demographic started with a disrupted microbiome and utilized probiotics to alter/improve the situation.

Examples studied included conditions like IBS, eczema and bacterial vaginosis.

Technically speaking, the studies I referenced in my previous pieces on PCOS and Fatty Liver would fall into this category. 

Of the studies that fit the review criteria, McFarland found that probiotics were effective in 56% of them.

This also makes sense intuitively because probiotic use is studied for multiple disease states but given the complexity involved they simply aren’t always effective at improving outcomes.

#3  Healthy Demographic

Now this is where it gets interesting!

This final demographic focused on studies using healthy volunteers who had no suspected dysbiosis and were provided probiotics to determine whether or not they made meaningful alterations or improvements to the gut microbiome.

The effectiveness rate in this demographic was only 21%, speaking to the fact that most health professionals sympathize with – “Not everyone needs a probiotic!”.

Final Thoughts

I felt compelled to write today’s article because it offers a broad yet intriguing overview of the various capacities in which probiotic supplements are most effective.

Whether you are a health professional communicating to patients about probiotics or an individual curious about them generally, I’d like to think that this content has enhanced your understanding.

With that being said, the determination as to whether or not probiotic supplementation is right for you is highly individualized and while these guiding criteria will help – they don’t replace the knowledge and strain-specific knowledge of your healthcare provider. 


  1. U.S. Department of Health and Human Services. (n.d.). Statistics from the National Health Interview Survey. National Center for Complementary and Integrative Health. Retrieved December 15, 2022, from 
  2. McFarland L. V. (2014). Use of probiotics to correct dysbiosis of normal microbiota following disease or disruptive events: a systematic review. BMJ open, 4(8), e005047.

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