If you regularly take probiotic supplements but find your gastrointestinal issues are not improving, it is unlikely that greater strain diversity, larger doses, or refrigeration will make a difference. Traditional probiotics are simply insufficient to strengthen the gut microbiome.
Approximately 100 trillion microorganisms, both good and bad, live inside a healthy digestive system. However, poor diet, lack of exercise, and genetic factors can fuel rapid growth of harmful bacteria, resulting in indigestion, bloating, and bowel issues. Probiotics seek to transport live cultures to your colon, where they can support good bacteria and drive out the bad. Unfortunately, most of these beneficial strains cannot survive the hostile, acidic environment inside the stomach and small intestine. Traditional probiotics attempt to compensate by including tens of billions of bacteria colonies in each capsule so that some will reach the colon safely, but large doses can often upset your stomach even more.
In good news, researchers have recently discovered smart probiotic strains that are naturally resistant to stomach acid in their dormant, shelf-stable state. Known as spore-forming probiotics, they only activate once inside colon, where they can effectively fight bad bacteria, fortify your gut microbiome, and reduce gastrointestinal distress.
How Can You Tell a Good Probiotic Supplement from a Bad One?
Recent surveys indicate that while 1 in 3 people regularly takes probiotics for stomach and intestinal issues, only a small fraction have upgraded to formulas with spore-forming bacteria strains so far. However, with more individuals learning about these smart cultures and the growing body of clinical evidence that proves their superiority to traditional probiotics, public demand for spore-forming probiotics is expected to skyrocket.
And yet, many companies have ignored these new developments. The fast-growing market for probiotics has incentivized the release of ineffective supplements containing high doses of traditional probiotic cultures with little or no proof of safety or efficacy. That's why our staff decided to review all the most popular probiotic formulas today and evaluate them for safety and effectiveness. We will show you what to look for, what to avoid, and which products we determined to be the best.
In our analysis, we noticed a number of companies claiming a wide variety of health benefits from using their products, not all of which are likely. What kind of results can you realistically expect from a probiotic supplement?
When Will You See Results?
While traditional probiotic cultures can provide some noticeable relief within 30 days, high-efficiency spore-forming probiotics have been shown to improve stomach and intestinal issues faster and more effectively in much lower doses. However, regardless of the type of probiotic you take, longer periods of consistent use typically yield greater benefits for gastrointestinal health and gut microbiome diversity.
Research suggests that 3 months of daily use helps significantly increase the likelihood of lasting improvement. Here is a reasonable timeline to expect:
- Month 1: You may sense a reduction in the severity of bloating, digestive distress, and bowel urgency, rendering these issues less intense and more manageable.
- Month 2: You may notice you are more regular and have less frequent stomach issues, resulting in fewer limitations and disruptions to your daily routine.
- Month 3: Maximum microbiome support is reached. You may benefit from long-lasting relief from gastrointestinal discomfort, reliable and predictable bowel movements, and the freedom to live your life without worrying about the location of the nearest bathroom.
Tip: For best results, focus on consistency. Adding an effective probiotic supplement to your daily routine for at least 3 months promotes exponential improvement, as each dose builds on the benefits of the last.
So, what characteristics distinguish top-tier probiotics from the rest of the pack?
The 3 Must-Have Probiotic Cultures for Optimal Gut Health
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Bacillus Subtilis
Naturally found in soil and compost, Bacillus subtilis is a safe species of spore-forming bacteria. Found to survive for 6 years on NASA space satellites, these tough microorganisms can survive extreme heat, dryness, and acidity, making them ideal probiotics. Taken as a supplement, they remain dormant throughout the digestive tract until they reach the colon, where they help normalize bowel movements and protect the gut-blood barrier. Studies have shown Bacillus subtilis helps promote a positive balance of good to bad bacteria in the gut by supporting Lactobacillus and Bifidobacterium while suppressing Escherichia, Shigella, and Staphylococcus.
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Bacillus Coagulans
Present in fermented foods such as sauerkraut and kimchi, Bacillus coagulans is another strain of beneficial bacteria that organically forms endospores. Because this natural defense mechanism ensures their survival throughout the gastric tract, these smart cultures can provide comprehensive probiotic support in doses a fraction of the size of traditional probiotics, minimizing any potential side effects for sensitive stomachs. In addition to promoting the growth of good gut bacteria, Bacillus coagulans has been shown to be particularly effective in reducing painful gas, bloating, and abdominal distension while also improving bowel regularity.
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Bacillus Clausii
A spore-forming probiotic strain with an excellent safety profile, Bacillus clausii can be found organically in plant soil and on the surface of fresh-grown vegetables. Research shows that these endospores are able survive and replicate after more than 4 hours of exposure to gastric fluids, while traditional probiotics like Lactobacillus and Bifidobacterium perish after only 30 minutes. It is this natural resistance to acidity that allows these beneficial cultures to thrive inside the gastrointestinal tract, where they help strengthen the lining of the colon against harmful microbes, fight pathogenic bacteria and viruses, and protect against loose stools and bloat.
Perhaps even more important, there are certain red flags to be wary of when evaluating a probiotic supplement.
Warning Signs of Potential Scams and Safety Issues
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Lack of Clinical Studies
Be wary of companies that cite the clinical efficacy of individual ingredients within a product rather than the effectiveness of the product as a whole. The highest indicator of quality in a supplement is the commission of a placebo-controlled clinical study for safety and effectiveness by an independent third party. You expect the same high standard of research and testing before trusting a medication, so why wouldn't you do the same before trusting a supplement?
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Traditional Probiotic Cultures
Although many healthcare practitioners now exclusively recommend spore-forming probiotics, most options available to consumers still center around traditional probiotic strains. These obsolete supplements typically try to create the illusion of efficacy with a high CFU count or a large number of different bacteria cultures. However, unlike endospores, the vast majority of traditional probiotics cannot even survive 1 hour in the hostile environment of the human digestive system, let alone several days or weeks in a shipping box on the way to your doorstep.
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Unproven Bacteria Strains
While many probiotic cultures are beneficial for gut health, not all have a proven track record of safety and effectiveness. In the interest of novelty, some companies feature less-researched species that can cause harm to the gut, starving out beneficial bacteria in the competition for resources and producing gastrointestinal distress. For this reason, it is important to take supplements only containing strains with unambiguous safety profiles rather than exotic strains with questionable reputations.
Top 5 Probiotic Supplements of 2024
Here is a side-by-side comparison of the top probiotic formulas available today, which provides a summary of our research and analysis:
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| Key Ingredients | |||||
| Bacillus Coagulans | Yes | Yes | Yes | Yes | Yes |
| Bacillus Subtilis | Yes | Yes | Yes | Yes | No |
| Bacillus Clausii | Yes | Yes | Yes | Yes | No |
| Safety and Efficacy | |||||
| Placebo-Controlled Clinical Study | Yes | No | No | No | No |
| Only Spore-Forming Strains | Yes | Yes | Yes | No | No |
| No Unproven Probiotic Cultures | Yes | Yes | No | Yes | Yes |
| Other Considerations | |||||
| No Artificial Additives | Yes | Yes | Yes | Yes | Yes |
| Vegan | Yes | Yes | Yes | Yes | Yes |
| Non-GMO | Yes | Yes | Yes | Yes | Yes |
| Gluten-Free | Yes | Yes | Yes | Yes | Yes |
| Made in a GMP-Certified Laboratory | Yes | Yes | Yes | Yes | Yes |
| Made in the USA | Yes | Yes | Yes | Yes | Yes |
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Below, we break down our rankings and feature detailed reviews of the 5 best probiotics we analyzed, beginning with our top pick.
Pros
- Clinically tested against placebo by independent third party
- 95% of study participants reported improved digestion, bowel movements, and gut health within 30 days*
- Contains all 3 must-have ingredients
- No fillers or artificial additives
- Vegan, non-GMO, and gluten-free
- Made in the USA
Cons
- Available online, but not currently sold in retail stores
The Bottom Line
We gave 3Biome by Nutreance our #1 ranking because it is the only probiotic supplement that meets every one of our strict criteria.
3Biome was clinically tested for safety and effectiveness over the course of 30 days in a placebo-controlled clinical trial conducted by Princeton Consumer Research. The study showed that people taking 3Biome saw significant improvements in bowel regularity, digestive discomfort, and stomach issues compared with placebo. (Click here for the complete study results).
3Biome contains all 3 of the spore-based bacteria cultures we consider essential to relieve digestive distress, improve bowel movements, and ensure a healthy gut microbiome, including Bacillus subtilis, Bacillus coagulans, and Bacillus clausii. 3Biome also does not feature any exotic or unproven bacteria species, solidifying its best-in-class safety profile.
It is available on Amazon.com, but we found significantly better discounts on Nutreance's website. The company also offers other products for gastrointestinal issues, including a digestive enzyme formula and a liver support supplement.
Overall, 3Biome is our top pick for probiotic support in 2024.
Click here to visit the product website.
* Results may vary and do not necessarily reflect typical results of using this product. Please visit product website for more information.
Pros
- Exclusively contains safe strains of spore-forming bacteria
- Contains all 3 must-have ingredients
- No fillers or artificial additives
- Vegan, non-GMO, and gluten-free
- Made in the USA
Cons
- No clinical study
The Bottom Line
ProbioSpore by Designs for Health provides effective microbiome support with a strong cast of spore-forming strains, including all 3 beneficial bacteria that we look for in a quality probiotic supplement: Bacillus subtilis, Bacillus coagulans, and Bacillus clausii.
Devoid of traditional probiotic strains, the product contains only spore-forming bacteria, which are naturally resistant to heat and stomach acid to ensure their survival until they arrive in the large intestine. In addition, the formula avoids the use of any newly discovered or questionable strains without an already established, favorable safety profile.
Unfortunately, the product as a whole has not been tested for safety or effectiveness against placebo. While each individual component of the formula is strong, the overall performance of the formula cannot be determined without a scientific evaluation of the product as a whole. Since other probiotics are available which are backed by clinical evidence, we cannot give ProbioSpore our highest rating.
Click here to visit the product website.
* Results may vary and do not necessarily reflect typical results of using this product. Please visit product website for more information.
Pros
- Spore-based probiotic formula
- Contains all 3 must-have ingredients
- No artificial additives
- Vegan, non-GMO, and gluten-free
- Made in the USA
Cons
- No clinical study
- Contains 2 probiotic strains with questionable safety and efficacy
The Bottom Line
Mega SporeBiotic by Microbiome Labs is a spore-based formula which includes 3 live cultures essential for gastrointestinal health: Bacillus subtilis, Bacillus coagulans, and Bacillus clausii.
In addition to these core beneficial bacteria, Mega SporeBiotic features 2 supplemental strains: Bacillus indicus and Bacillus licheniformis. However, their inclusion is questionable, as neither has a proven track record of safety or effectiveness in humans.
Although some literature suggests that Bacillus indicus can provide benefits for bowel regularity, none of the studies of this strain's safety and efficacy have involved human subjects, conducted instead only on animals or in vitro. Likewise, human studies of Bacillus licheniformis as a beneficial probiotic are lacking, with only 4 published as of this writing. Moreover, according to the United States Environmental Protection Agency, this particular species can produce gastrointestinal distress in immunocompromised individuals or when consumed in high concentrations.
A clinical study would go a long way to validate the formula's safety and efficacy, but none have been conducted yet for this product.
Click here to visit the product website.
* Results may vary and do not necessarily reflect typical results of using this product. Please visit product website for more information.
Pros
- Contains all 3 must-have ingredients
- No artificial additives
- Vegan, non-GMO, and gluten-free
- Made in the USA
Cons
- No clinical study
- Contains a probiotic yeast which commonly causes gas, bloating, and constipation
The Bottom Line
Multi-Probiotic by Douglas Laboratories features all 3 of the probiotic strains we consider must-haves for optimal gut health. Bacillus subtilis, Bacillus coagulans, and Bacillus clausii are joined in this formula by a probiotic yeast known as Saccharomyces boulardii. As it is a fungus, not a bacteria, it cannot form acid and heat-resistant endospores. This microorganism is generally considered superior to traditional probiotic bacteria in its ability to survive the journey through the human digestive tract. However, it is not well-suited to withstand the wide temperature fluctuations common during transit in a shipping box.
While typically present in most healthy microbiomes, introducing Saccharomyces boulardii to the gut via supplementation has been linked with higher incidence of gas, bloating, and even constipation. Since Multi-Probiotic has not been clinically studied and its safety profile is not fully established, some caution may be warranted. Purchasing separate spore-based probiotic and Saccharomyces boulardii supplements may be a better option to minimize the potential for any side effects if you choose to explore your body's tolerance for this yeast.
Click here to visit the product website.
* Results may vary and do not necessarily reflect typical results of using this product. Please visit product website for more information.
Pros
- Contains Bacillus coagulans
- No artificial additives
- Vegan, non-GMO, and gluten-free
- Made in the USA
Cons
- No clinical study
- Does not contain Bacillus subtilis or Bacillus clausii
- Contains an ingredient with limited proof of efficacy
The Bottom Line
ProbioMax by Xymogen contains Bacillus coagulans, one of the safest and most effective spore-forming probiotics for bowel regularity and gastrointestinal support. Unfortunately, it is the only species of beneficial bacteria included. Though a large number of different strains is not strictly necessary for optimal gut health, a well-rounded probiotic supplement typically includes at least 2 or 3. Adding Bacillus subtilis and Bacillus clausii would significantly bolster the formula's effectiveness while maintaining a strong safety profile.
The product also prominently features hyperimmunized egg powder, extracted from the eggs of vaccinated hens. Once immunized, the hens transfer antibodies to their egg yolks, providing immune benefits to the chicks that hatch from them or the individuals who eat them. While there is some evidence that this ingredient can boost immune health, there is limited evidence that it can help defend against pathogenic bacteria and other harmful microbes in the gut.
They have not tested the product for safety and effectiveness in a placebo-controlled clinical study.
Click here to visit the product website.
* Results may vary and do not necessarily reflect typical results of using this product. Please visit product website for more information.