How Often Should You Take Probiotics? – A Complete Guide

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By Thomas Youngerman

Reviewed by Juliana Tamayo, MS, RDN - Last Updated

How Often Should You Take Probiotics

This article will attempt to answer the question of how often should you take probiotics. It’s complicated – and it depends. We’ll address the question based on scientific data rather than quoting the advice offered in probiotic manufacturers’ sales and marketing materials.

Although we’re confident you are familiar with probiotics and prebiotics, we will first define and explain the role of each and their symbiotic relationship. Next, we will explain the identification of specific probiotics strains and cite several prominent organizations regarding their clinical evidence supporting their benefits. Finally, we will provide examples of several of the best probiotic products on the market today. 

Probiotic Supplements

Probiotics, Prebiotics, And Synbiotics – Defined


Probiotics are the fastest-growing category in the nutritional supplement space. Per Grand View Research, the global probiotics market is estimated at over $48 billion and is forecast to continue to grow at an accelerated rate. So, we were not surprised that there is an International Scientific Association for Probiotics and Prebiotics. Who better to provide our definition of probiotics:

“Probiotics” are “live microorganisms that, when administered in adequate amounts, confer a health benefit on the host.” These microorganisms consist mainly of bacteria but also include yeasts, are naturally present in fermented foods, may be added to other food products, and are available as dietary supplements.” 

Probiotics For Gut


Not to be confused with probiotics are prebiotics, complex carbohydrates that promote the growth of beneficial microorganisms in the gastrointestinal tract. Prebiotics are typically types of dietary fibers that feed the friendly bacteria in your gut leading to a healthier digestive system. 


 Products that contain both probiotic organisms and prebiotics are often called “synbiotics” due to their synergism.

How Often Should You Take Probiotics?

As we stated at the outset, this is a difficult question, and the answer is “it depends.” First, addressing the problem strictly from a safety point of view, the general answer is that it is safe for healthy individuals to take probiotics daily. However, if you eat a nutritious, balanced diet, the medical community is unsure if probiotic supplementation is necessary – and if you don’t have a healthy diet, they are uncertain if probiotics will improve your digestive health. 

Perplexed, we turned to the WGO (the World Gastroenterology Organization) for their position. Here’s where “it depends” comes into play:

 “The dose needed for probiotics varies greatly depending on the strain and product. Although many over-the-counter products deliver in the range of one to ten billion CFU (colony forming units) per dose, some products have been shown to be efficacious at lower levels, while some require substantially more.”

As we like to say, it appears the data is “mixed.”

Probiotic Capsules

Identifying Your Probiotics

In this instance, mixed data is precisely what we should expect because specific probiotic strains have different actions and address different issues. To analyze and scientifically study probiotics strains, they must be identified by their genus, the species, the subspecies, and an alphanumeric designation. The types of microbial organisms most frequently used in commercial probiotic products are Lactobacillus, Bifidobacterium, Saccharomyces, Streptococcus, Enterococcus, Escherichia, and Bacillus. 

Measuring Your Probiotics 

Probiotics are measured in colony-forming units (CFU), which indicate the number of viable (living) cells. Although many probiotic supplements contain from one to ten billion CFU per dose, some brands may contain up to fifty billion or more. One of the more respected brands in the space, Garden of Life, has a Men’s product for immune health with eighty-five billion CFU and an Ultimate Care product with one hundred million CFU. 

Current labeling regulations only require manufacturers to list the microorganisms’ total weight on a probiotic product’s Supplement Facts panel. We recommend you do your due diligence, as probiotics must be consumed alive to derive health benefits. Returning to Garden of Life, both examples listed above “guarantee” that the number of CFU on the label are live cultures.

Sources Of Probiotics

Almost as confusing as to how often you should take probiotics is how you should take your probiotics. Probiotic-containing products are available in an array of different types, from conventional food through prescription drugs.

Fermented Food

Many fermented foods are rich sources of live and potentially beneficial microbes. However, some foods are processed after they are fermented; thus, they do not contain live cultures. Other commercial items, such as yogurts, contain probiotic microorganisms, such as Lactobacillus bulgaricus and Streptococcus thermophilus. The issue is that although these microorganisms survive well enough in the product, they do not always make it through the small intestine. 

Unfermented Foods

Other unfermented foods such as milk, juices, smoothies, and infant formulas have added microorganisms. If a product is a real probiotic, its organisms must survive the product’s shelf-life, intestinal transit, and have health effects.

Meal Replacements

Designed for people with unique nutritional requirements.

Dietary Supplements

Probiotics are also available as dietary supplements. They come in several different forms, capsules, powders, liquids, and gummies, and typically contain mixed cultures of live microorganisms rather than single strains. Returning to our Garden of Life examples above, the Men’s immune health product with eighty-five billion CFU has fifteen probiotic strains, and the Ultimate Care product with one hundred million CFU has thirty-four strains.  

The chart below illustrates the variety of strains and potencies (# Cultures/CFU) in some of the more popular probiotic brands in the natural products space. 

The quality of probiotic supplements depends greatly on the manufacturer’s integrity since the FDA does not regulate dietary supplements. Dosages vary greatly depending on the strain and product. Because probiotics are alive, they are susceptible to expiring during product storage. Responsible manufacturers build in overages so that it does not fall below the potency declared on the label at the end of the product’s shelf-life. 

Over The Counter And Prescription Drugs

These pharmaceutical products usually are doctor prescribed for people needing to prevent or treat specific diseases.  

The Benefits Of Probiotics

Probiotics are proven to improve digestive health, reduce intestinal inflammation, and bolster your immune system. If you want to stay healthy, taking care of your gut health to power up your natural defenses is paramount.

As new strains of probiotics and new probiotic formulations are introduced, product benefits are being extended beyond gut health. Benefits now include women’s health, cardiovascular health, cognitive function, skin health, athletic performance, weight management, mood, and overall wellbeing. Let us repeat, applications and results are strain-specific. Clinical evidence must be linked to specific formulations defined by genus, species, strain, and the number of live bacteria present.

The probiotic benefits most frequently claimed by nutritional supplement manufacturers for probiotics include:

  • Constipation
  • IBS Irritable Bowel Syndrome
  • Antibiotic-Associated Diarrhea
  • Migraine Prevention
  • Oral Health
  • Mood and Stress
  • Ulcerative Colitis
  • Weight Management
  • Women’s Health

As promised, we will refer to clinical studies to determine which of these structure-function claims are substantiated by scientific evidence. Results from at least one well-designed clinical trial prove that oral administration of a specific probiotic strain is safe and effective.

Clinical Evidence Relating To The Efficacy Of Probiotics

Below is a partial list of published clinical trials to address specific health issues conducted on various probiotic strains. The list is far from complete as the publication of new studies continues at a rapid pace. For a more comprehensive review of the strains of probiotics, prebiotics, and their synbiotic actions to address various health disorders, visit the World Gastroenterology Organization Global Guidelines. Below are excerpts from the WGO report.

  • Diarrhea treatment and prevention – some probiotic strains reduce the severity and duration of acute infectious diarrhea in children. 
  • Prevention of acute diarrhea – there is evidence that certain probiotics can be effective in some specific settings.
  • Prevention of antibiotic-associated diarrhea – there is significant evidence of efficacy in adults or children who are receiving antibiotic therapy.
  • Prevention of radiation-induced diarrhea – a 2013 meta-analysis concluded that probiotics might be beneficial in preventing and possibly treating radiation-induced diarrhea.
  • Immune response – evidence suggests that several probiotic strains and the prebiotic oligofructose are useful in improving the immune response. 
  • Ulcerative colitis – certain probiotics are safe and as effective as conventional therapy in achieving higher response and remission rates in active ulcerative colitis.
  • Irritable bowel syndrome (IBS) – a reduction in abdominal bloating and flatulence resulting from probiotic treatments is a consistent finding in published studies; some strains may alleviate pain and provide relief. 
  • Colic – certain probiotic strains have been shown to reduce crying time in breastfed infants with colic.
  • Lactose malabsorption – Streptococcus thermophilus and Lactobacillus delbrueckii improve lactose digestion and reduce symptoms related to lactose intolerance. 
  • Nonalcoholic fatty liver disease – the use of certain probiotics as a treatment option to mitigate steatohepatitis has been proven through randomized clinical trials in adults and children.
Clinically Proven Probiotics

As clinical studies accelerate, probiotics have been shown to affect clinical outcomes outside the normal gastrointestinal disease realm. Emerging evidence suggests that the gut microbiome may affect non-gastrointestinal conditions, such as reducing the incidence and duration of upper respiratory tract infections. Ongoing clinical trials are testing probiotics to prevent some manifestations of metabolic syndrome, including excess weight and type-2 diabetes.

Are Probiotics Safe?

Probiotics are generally considered safe for most people. Side effects are usually minor and consist of stomach issues such as gas, bloating, and constipation, until the body becomes accustomed to using them. 

Our position is to always check with your medical professional before adding a new supplement to your regimen. If you are considering a probiotic to address a specific issue, you should discuss your best course of action with your doctor or a registered dietician. 

People who have an immune deficiency or are treated for cancer should not use probiotics without a doctor’s okay.

Best Probiotic Supplements

The above chart lists some of the largest probiotic brands from respected manufacturers. All these brands adhere to the criteria we employ when selecting the “Best of” products; however, we picked two brands at the forefront of probiotic product development and research for this article. 

When making our selections, we adhered to the following criteria:

  • Our preference for patented, clinically tested ingredients played a significant role in our choices.
  • We ensured the products are manufactured in the U.S. in a certified cGMP facility (Good Manufacturing Practices). 
  • We looked for companies and brands that have independent third-party testing for quality and purity.
  • Having a Money-Back Guarantee was important to us as it indicates the manufacturer’s confidence in its product.

Gundry MD

Gundry MD is an online presence with an extensive array of products, from supplements to skin and haircare, foods, dog food, magazines, and books. Their supplement offerings cover everything from vitamins to BCAAs, joint health, cardiovascular health, and their primary focus digestive health – products to support the microbiome. 

The company’s founder is Dr. Steven Gundry. After a long and distinguished career as one of the world’s pre-eminent experts in heart surgery, Dr. Gundry left his position as Head of Cardiothoracic Surgery at California’s Loma Linda University Medical Center in 2002 and founded The Center for Restorative Medicine. He has spent the ensuing years studying the human microbiome, writing several New York Times bestsellers, and developing his principles of “Holobiotics.” His Center, “Holobiotics,” and his published works focus on lifestyle, nutrition and diet, and their relationship to the human microbiome.

Dr. Gundry has emerged as one of the industry’s leading experts on the microbiome, gut health, and its role in immune health. Below is a list of the products he has developed for digestive health: 

  • Gundry’s Bio Complete 3 – pre, pro, and postbiotics 
  • 24 Strain Probiotic – probiotics
  • Total Restore – to promote a strong, healthy gut lining
  • PrebioThrive – prebiotics
  • GI Renew – digestive enhancement
  • Metabolic Advanced – metabolic support
  • Lectin Shield – to eliminate toxic proteins
  • Primal Plants – improves digestion
  • Power Blues – contains pre and probiotics

Gundry MD Bio Complete 3


Our first “Best of” offering is Gundry’s Bio Complete 3, a dietary supplement in vegetable capsule form, which includes three proprietary trademarked, all-natural ingredients, a prebiotic, probiotic, and postbiotic. Dr. Gundry refers to the formulation as his 3-Pronged Defense for gut health: 

  1. Probiotics to provide an abundance of good gut bacteria
  2. Prebiotics providing fuel for the good bacteria 
  3. Postbiotics to support the gut lining and to alleviate symptoms of “leaky gut”  

The product is manufactured in the U.S. in a certified cGMP (current Good Manufacturing Practices) facility, and the formula is quality and purity tested at an independent, third-party lab. Bio Complete 3 is sugar-free, gluten-free, free of soy, dairy, lectins, and artificial sweeteners. Like all Gundry MD products, Bio Complete is supported by a ninety-day money-back guarantee. These are all best in class standards within the nutritional supplement industry


Gundry MD 24 Strain Probiotics

Gundry MD 24 Strain

Another solid choice from Gundry MD is their 24 Strain Probiotic, a dietary supplement in vegetable capsule form, which includes twenty-four unique probiotic strains to provide an abundance of good gut bacteria, 30 billion CFUs per serving. Dr. Gundry specially formulated the product to protect your healthy probiotic bacteria against digestive dangers, including the modern American diet, antibiotics, and environmental factors.

24 Strain Probiotic is manufactured in the U.S. in a certified cGMP (current Good Manufacturing Practices) facility, and the formula is quality and purity tested at an independent, third-party lab. The product is sugar-free, gluten-free, free of soy, dairy, lectins, and artificial sweeteners. Like all Gundry MD products, 24 Strain Probiotic is supported by a ninety-day money-back guarantee. 


Seed Daily Synbiotic

Seed Daily Synbiotic

No, the company didn’t misspell symbiotic, an interaction between two different organisms located in close proximity in a mutually beneficial relationship. Seed Daily Synbiotic refers to a mixture of prebiotics and probiotics that improve the survival rate and activity of beneficial microorganisms in the gut.

Seed uses an ingenious delivery vehicle for its pre and probiotic blend. Inside an outer capsule with built-in prebiotics, there are twenty-four strains of probiotics supporting digestive, dermatological, cardiovascular, and gut-immune health. A standard dose, two capsules, delivers over 53 billion AFUs Active Fluorescent Units, that the company states is a more precise method of measurement than CFUs.

A thirty-day supply, sixty capsules, sells for $49.99 on the company website and includes a handy travel vial at no charge. We love the simplicity of the packaging and messaging.


Stacking Probiotics

Probiotics can be stacked with virtually any other supplement depending on your health and fitness goals. Staying in gut health, we recommend stacking your probiotic with a prebiotic and perhaps a postbiotic, a newer development in the microbiome arsenal. Some modern formulations in the space incorporate all three, pre, pro, and postbiotics in a single product. 

To Summarize: Probiotic Supplements

The science supporting probiotic supplementation efficacy is sufficient for us to endorse adding a probiotic to your regimen. As to our question, how often should you take a probiotic, we’ll refer to the WGO (World Gastroenterology Organization) once again:

“The WGO notes that the optimal dose of probiotics depends on the strain and product. The organization, therefore, recommends that clinicians who advise their patients to use probiotics specify the probiotic strains, doses, and duration of use that studies in humans have shown to be beneficial.”

Stated differently, the data is mixed, dosages vary by strain and by product, so no general dosing recommendation can be made. Standard dosages for adults range from five billion to ten billion CFU per day. 

And finally, we recommend you take just one dose of probiotics per day.

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Thomas Youngerman

Thomas Youngerman is an entrepreneur and author in the health and wellness space with extensive experience in the supplement industry. He has owned multiple sports nutrition stores and served as the Category Manager and Director of Business Development for a regional chain of nutrition stores. Thomas created a successful line of men’s healthy aging supplements that was distributed in GNC, The Vitamin Shoppe, and Kroger, and later sold to a West Coast corporation. Thomas was previously a certified nutrition coach. He has a strong understanding of nutrition, supplement formulations, DSHEA, cGMP, and FDA regulations.