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How to Choose the Best Probiotic Supplement

By Brandi Givens, RDN

Medically Reviewed by Anthony Dugarte, MD

Last Updated on February 17, 2022

With the overwhelming options available online and at the pharmacy, finding the right probiotic supplement can be confusing. But, with a bit of guidance and attention to specific needs, you can find the product that’s right for you.

Written by
Brandi Givens, RDN
Registered Dietitian Nutritionist
Brandi Givens has been a registered dietitian nutritionist (RDN) since 2010, and an internationally board-certified lactation consultant (IBCLC) since 2016.
Medically Reviewed by
Anthony Dugarte, MD
Medical Reviewer
Anthony Dugarte, M.D., C.S.C.S. is a health and wellness writer and medical content reviewer. In addition to dedicating the last 7 years to medical research, Dr. Dugarte also has more than a decade of experience in strength and conditioning, nutrition, and rehabilitative exercise, as well as authoring and reviewing health and wellness-related content.
How to Choose the Best Probiotic Supplement
Photo by WellnessVerge

Probiotics are microbes that we can eat in food or take as supplements that make us healthier. (1)

When we eat probiotics, we’re trying to increase the diversity and numbers of the helpful microbe colonies that live in our digestive system.

The world of microbes is called our gut microbiome. Humans have been reaping the benefits of probiotic foods for thousands of years.

Without realizing we were eating living microbes, cultural fermented foods like yogurt, kefir, and sauerkraut have always been loaded with them.

What Are Probiotic Supplements?

Until a couple of decades ago, gut bacteria weren’t given much thought and were just considered either useless or harmful.

Then scientists started investigating the microbes, and evidence of their benefits began emerging. The discoveries began culturing a new market for probiotic supplements.

Probiotic supplements are bottled (shelf-stable or refrigerated) living probiotic microbes that can be purchased at many retailers. Some people take them daily, just like vitamin supplements.

Today, the abundance of probiotic supplement choices can be overwhelming and confusing. People may wonder if they need a supplement and how to select the right one.

Why You May Need to Supplement

Each person’s gut microbiome is unique as a fingerprint.

Hundreds of strains of microbes, including bacteria, protozoa, fungi, and viruses, colonize the gut during birth, breastfeeding, early childhood, and beyond.

Since no two people have the same exact exposures, no two microbiomes are the same.

Although scientists are still learning the details, we know that most of the microbes living within us offer a kind of symbiosis.

Over the course of each person’s life, the microbiome changes, sometimes drastically.

For example, using one round of antibiotics can upset the entire gut microbiome. This is because antibiotics can’t discriminate between helpful bacteria and the bad bacteria they’re intended to destroy.

We also know now that keeping our world overly clean with antibacterial or sanitizing solutions robs us of opportunities to colonize friendly microbes in our gut.

And finally, poor-quality diets, often low in fiber-rich prebiotic foods, starve our good microbes, allowing room for harmful microorganisms to move in.

Because of the lack of exposure and negative changes to our microbiome over time, adding probiotic foods and supplements to your routine can sometimes be beneficial.

Related: 10 Evidence-Based Ways to Improve Your Gut Health

How to Choose a Probiotic Supplement

1. Research Your Condition

If you are considering taking a supplement or new medication of any kind, it’s always best to talk to your doctor first to make sure they’re right for you.

Your doctor or dietitian may also be able to provide the most recent research regarding probiotics for your specific condition.

Probiotics show promise for treating several conditions. But with other conditions, the evidence may be inconclusive and is often exaggerated to the public.

Research studies regarding probiotics have piled up into the thousands. Weeding through the information is a challenge and is sometimes unclear, even for experts.

This is a great reason to get help from a healthcare professional before deciding whether supplementation may work for you.

Before your doctor’s visit, a great place to start your own research is through well-respected organizations like the National Institutes of Health, the American Gastroenterological Association, or educational institutions like Mayo Clinic, all of which offer evidence-based information.

2. Picking the Right Genus, Species, and Strain Matters

Let’s go back to biology class for a moment. Scientists name microbes by genus, species, and strain.

Now we’ll use the bacterium Lactobacillus rhamnosus GG as an example. The genus is Lactobacillus, the species is rhamnosus, and the strain is GG.

This is important to know because scientists think probiotics behave in a species or even strain-specific manner. Specific microbes seem to work best for treating different conditions.

For example, Lactobacillus rhamnosus seems to work well for IBS patients, while Lactobacillus delbruekii is better for people with lactose intolerance.

The box label on a good probiotic supplement should show which microbes are in each product.

There are a few examples below of which conditions are treated best by which probiotic, but this information is changing rapidly. It’s best to discuss it with a specialist.

3. Consider the Safety

Choose a probiotic supplement with microbes that have been studied for safety and side effects.

Once you’ve narrowed down the strains you’re looking for, your doctor can help you find information regarding safety and any adverse side effects on your specific strain.

Probiotics fall under the category of supplements, which gives the FDA minimal control over safety regulations. (2)

However, the most common microbes used in probiotic supplements are several strains of the Lactobacillus and Bifidobacterium bacteria.

The World Gastroenterology Organization (WGO) thinks consuming these microbes is low risk because they’re found in many probiotic foods that have been consumed for centuries. Plus, they’re found in abundance in healthy human intestines. (3)

The National Institutes of Health report that there have been very few reported adverse effects from probiotic supplements, even for fragile, premature infants. (4, 5)

Most adverse effects are minor, like gas, but a small number of cases involving immunocompromised people resulted in severe infections.

4. Get Enough CFUs

Be sure that the supplement has adequate active colony-forming units (CFUs). CFUs are microbes that are still viable (not dead), so they can potentially form colonies in your gut.

It isn’t yet clear how many CFUs are necessary for treatment in most cases, but a general rule is that your supplement should contain at least 1 billion CFUs of each strain.

Some probiotic supplements advertise many more CFUs than that, sometimes as many as 50 billion, but it’s unclear whether more is better.

Consider that starting with a lower end of one billion CFUs may help your gut ease into probiotics, avoiding uncomfortable gas and bloating.

Be certain the label guarantees that the CFUs are viable (or alive) through the shelf life of the product – not just at the time of manufacturing.

Probiotic bacteria must be alive to provide any benefit to their host.

5. Go With Third-Party Testing When Possible

Poor regulation and lack of third-party testing are possibly the biggest barriers to research and professional recommendations in favor of probiotic supplements. Researchers have a hard time finding consistent samples to study and recommend.

To point out the problem, a researcher in 2015 found that only one product out of the sixteen tested matched its label claims. The study also found that the supplements varied from batch to batch and pill to pill. (6)

Try to find a supplement that has undergone testing by third parties like United States Pharmacopeia (USP), Consumer Labs, or NSF International to help ensure ingredients are as described on the label. (7)

6. Choose Probiotics That Have Been Properly Stored

It may be better to purchase probiotic supplements inside a reputable store or pharmacy rather than by mail because improper storage can destroy the organisms.

Microbes are especially sensitive to heat and moisture and may be destroyed by the time they reach you if their environments are not controlled.

This is especially true if the supplement needs refrigeration. Be sure to read the label to learn how to store them once you get them home.

7. Consider Synbiotics

Synbiotics are supplements that contain both the probiotic and the microbe’s favorite prebiotic fiber-rich food.

Synbiotics may help the microbe strain colonize once it’s introduced to the gut, which means the strain is more likely to continue thriving after the consumers have discontinued the product.

A supplement may be labeled as a synbiotic, or it may say that it contains both probiotics and prebiotics.

Remember that for the same reasons, a plant-based diet offers prebiotics that may help those new microbes thrive.

Related: Prebiotics vs. Probiotics: Differences, Benefits, Sources, and FAQs

Choosing Probiotics for GI Disorders

In 2017, the World Gastroenterology Organization (WGO) compiled a chart of evidenced-based cases in which probiotics have successfully treated specific gastrointestinal (GI) conditions. (3)

Below is a small sample of available research on GI conditions some probiotics may be able to treat.

The lists of microbes are not all-inclusive; they’re just a few from a handful of studies. And while WGO offered the most up-to-date information possible in 2017, new and more conclusive studies are emerging daily.

Disorder Probiotic and Prebiotic That May Help
Constipation Prebiotics fructooligosaccharides with Lactobacillus and Bifidobacterium 340
Acute Diarrhea L. paracasei B21060, L. rhamnosus, S. boulardii
Antibiotic-Associated Diarrhea Yogurt with L. casei DN114, L. bulgaricus, and S. thermophilus
IBS Multi-strain probiotic L. rhamnosus NCIMB 30174, L. plantarum NCIMB 30173, L. acidophilus NCIMB 30175, and Enterococcus faecium NCIMB 30176.
Lactose Intolerance (Maldigestion) S. thermophilus, L. delbruekii subspecies bulgaricus


A study in 2013 describes the effects of a synbiotic (a supplement that contains both probiotics and prebiotics). (8)

The product, which contained the prebiotics fructooligosaccharides with Lactobacillus and Bifidobacterium, improved constipation in elderly women.

Related: How to Get Rid of Constipation: Home Remedies and When to See a Doctor

Acute Diarrhea

Diarrhea has many causes, and the probiotic treatment of diarrhea seems to be species-specific according to the cause.

For example, acute diarrhea, or diarrhea that comes up suddenly and severely, has been shown to respond to S. boulardii.

In a meta-analysis of seven randomized control trials of a total of 944 children with acute diarrhea, S. boularidii reduced patient symptoms by a reduction of one day on average. (9)

Antibiotic-Associated Diarrhea

A 2012 systematic review and meta-analysis of probiotics in the prevention of antibiotic-associated diarrhea, which compiled results from L. acidophilus, L. rhamnosus, and S. boulardii studies, concluded that while these probiotics show overall success with preventing diarrhea, the inconsistency of the studies prevents knowing the best strain or dose to choose. (10)


Several studies have found evidence of probiotics offering relief for irritable bowel syndrome (IBS), a dysbiosis or imbalance of the gut that causes symptoms like gas, constipation, diarrhea, and bloating.

For example, in a study with 186 patients, a multi-strain probiotic showed a significant reduction in symptoms after 12 weeks of use. (11)

Lactose Intolerance

The European Food Safety Authority concluded that microbes found in some yogurt may alleviate the symptoms of lactose malabsorption. (12)

Choosing Probiotics for Other Disorders

Scientists now know that the entire body is affected by the health of the gut microbiome, which has resulted in ongoing probiotic research on conditions outside of the gastrointestinal system.

These studies offer a glance at some promising evidence.

Condition Probiotic That May Help
Weight Loss L. gasseri, L. rhamnosus, B. breve
Immune Health B. bifidum, L. gasseri, B. longum
Vaginal Health L. rhamnosis, L. acidophilus, L. fermentum
Mental Health B. longum

Weight Loss

Several studies show evidence that a healthy gut microbiome is connected to healthy body mass index and weight.

A 2020 review of studies discussed the relationship between poor diet and healthy gut microbiome as a cause for overweight, instead of just looking at it from a calorie perspective. (13)

Related: Probiotics and Weight Loss: Can Probiotics Help You Lose Weight?

Immune Health

A study in 2015 showed reduced inflammatory markers in elderly men with the use of probiotics. (14)

The results showed that the men’s bloodwork was closer to that of younger men after the study was complete.

Vaginal Health

There is some evidence that shows that probiotics are an effective way to treat bacterial vaginosis in some cases, as evidenced by a review of studies published from 1990–2011. (15)

Related: Best Probiotic Supplements for Women, According to Dietitians

Mental Health

In a study published in 2017, patients saw improvement in depression symptoms with the introduction to B. longum(16)

The Future of Probiotics

Top researchers at Stanford University have a vision of what is to come for probiotics. (17)

They’re trying to gain knowledge of how bacteria communicate with our bodies, which can lead to the improved use of probiotics.

Knowledge of what specific microbes are capable of will lead to better-targeted studies, which will then lead to more accurate recommendations of strains.

Stanford researchers also hope to see more use of synbiotics, which seems to be the best shot we have now to colonize probiotics.

The research could lead to increasing microbe populations and capacity to help their human hosts.

Finally, despite the thousands of studies that have been published in recent decades, there are no established health claims for probiotics, which hinders clinicians from recommending them.

This is likely because the studies are not robust enough to substantiate claims. More high-quality, sizable studies are needed to move forward.

Frequently Asked Questions

How do I know if I need a probiotic supplement?

If you are healthy and feel well overall, there’s no need to buy probiotic supplements. People who need them are generally looking for solutions to digestive or other issues.

If this is the case, talk to your doctor to see if a probiotic supplement may be right for you.

Start by adding probiotic foods to your diet. These are foods that have been part of many cultures worldwide for thousands of years.

Probiotic foods have active, live cultures in them, and you may find that you feel even better than you did before when you eat them regularly.

Is it okay to take probiotic supplements every day?

Long-term safety for taking probiotics has not been studied well yet.

The World Gastroenterology Organization thinks that supplements are likely safe for most people if the supplement uses microbes that have been consumed in probiotic foods for centuries.

It’s best to talk to your doctor about taking probiotic supplements before you start and discuss a plan for how long you should take them.

Is it best to choose a refrigerated probiotic or a shelf-stable one?

There is no difference in effectiveness in refrigerated versus shelf-stable probiotics. Focus on choosing a quality product with the right types of microbes instead.

Should I give probiotic supplements to my child?

If your child has a medical condition that you think may be helped with probiotic supplements, you should speak to their doctor before buying them.

That way, your doctor can help you decide which one is best, or if they need them at all before you spend money on something that may not help.

The Bottom Line

It’s always best to get clearance from your doctor before trying any new medication or supplement, including probiotics.

Getting a proper diagnosis of your symptoms is important to rule out potential underlying conditions.

To be clear, the study of probiotics is in its infancy, and there is still a lot to learn before healthcare professionals can be certain when it comes to guidance. Some research is robust, while other studies lack quality.

Once there’s enough evidence for individual or groups of probiotic strains to treat conditions, the FDA can publish health claims, and medical professionals can more easily make solid recommendations.

Until then, consider probiotics to be a promising product that may or may not work for your condition.

Remember that an economical alternative to buying supplements is adding probiotic foods to your daily routine.

Foods like kefir, yogurt, sauerkraut, and kimchi offer good bacteria along with nutrition.

To keep those beneficial microbes happy and healthy, remember to eat a high fiber diet, providing prebiotic nutrition for the existing microflora population in your gut.

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At WellnessVerge, we only use primary references for our articles, including peer reviewed medical journals or well-respected academic institutions.

  1. Expert consensus document. The International Scientific Association for Probiotics and Prebiotics consensus statement on the scope and appropriate use of the term probiotic:
  2. FDA: Dietary Supplements:
  3. World Gastroenterology Organisation Global Guidelines: Probiotics and prebiotics:
  4. National Institutes of Health: Probiotics Fact Sheet for Health Professionals:
  5. Probiotics for prevention of necrotizing enterocolitis in preterm infants:
  6. Validating bifidobacterial species and subspecies identity in commercial probiotic products:
  7. USP Verified Products Listing:
  8. Effect of synbiotic in constipated adult women e A randomized, double-blind, placebo-controlled study of clinical response:
  9. Saccharomyces boulardii for treating acute gastroenteritis in children: updated meta-analysis of randomized controlled trials:
  10. Probiotics for the Prevention and Treatment of Antibiotic-Associated Diarrhea A Systematic Review and Meta-analysis:
  11. Randomised clinical trial: A liquid multi-strain probiotic vs. placebo in the irritable bowel syndrome--a 12 week double-blind study:
  12. Scientific Opinion on the substantiation of health claims related to live yoghurt cultures and improved lactose digestion (ID 1143, 2976) pursuant to Article 13(1) of Regulation (EC) No 1924/2006:
  13. Probiotics for the Treatment of Overweight and Obesity in Humans—A Review of Clinical Trials:
  14. Lactobacillus gasseri KS-13, Bifidobacterium bifidum G9-1, and Bifidobacterium longum MM-2 Ingestion Induces a Less Inflammatory Cytokine Profile and a Potentially Beneficial Shift in Gut Microbiota in Older Adults: A Randomized, Double-Blind, Placebo-Controlled, Crossover Study:
  15. Effects of probiotics on the recurrence of bacterial vaginosis: a review:
  16. Probiotic Bifidobacterium longum NCC3001 Reduces Depression Scores and Alters Brain Activity: A Pilot Study in Patients With Irritable Bowel Syndrome:
  17. Do probiotics live up to the hype? Part II: