Probiotic science

Why 60 Strains? The Science of Probiotic Diversity

What the research says about diversity, and what it doesn't

Our daily probiotics carry 60 to 100 strains. Is that meaningful, or just a bigger number? Here's an honest look at the evidence, and why we build them this way.

  • By Vital Planet
  • 8 min read
  • 11 studies cited

The evidence at a glance

  • 90bacterial groups made up a gut signature linked to more severe IBS; richness fell as symptoms worsened1
  • 65trials comparing mixtures with single strains mostly found them equal2
  • 12 of 16direct comparisons in an earlier review favored the mixture3

The short version

  • Researchers increasingly study the gut as an ecosystem,4 and diversity shows up in the data: in IBS, lower microbial richness went along with worse symptoms.1
  • But a probiotic's strain count isn't the same as your gut's diversity. Most probiotic strains pass through rather than settling in permanently.5
  • Head to head, multi-strain mixtures usually matched single strains for the same condition.2 An earlier review found mixtures ahead in 12 of 16 comparisons, but noted the higher total dose may explain it.3
  • We build high-diversity formulas for breadth: different strains have been studied for different things, and a diverse blend covers more of them in one capsule.* Named strains with evidence for your goal still matter most.

Walk down any supplement aisle and you'll see strain counts on the label: 10, 15, 30. Some products go past 60 or even 100. It raises a fair question: is more actually better, or is it a numbers game?

The honest answer is that it depends on what you're asking a probiotic to do. Here's what the research shows.

What research says about gut diversity

Your gut is home to a huge, varied community of microbes that differs from person to person and shifts over time, especially during illness and early life. Researchers increasingly look at it as an ecosystem.4

Symptoms

Richness tracked with IBS severity

In 149 people, those with more severe IBS had lower microbial richness, part of a 90-group bacterial signature.1

Aging

Changes at 105+

In people aged 105 to 109, the core gut community shrank with age, while Bifidobacterium, Akkermansia and other groups linked to health were more common.6

Disease

Shared patterns

Across 28 studies of ten diseases, some were marked by a loss of health-associated bacteria, and many changes were shared across diseases rather than specific to one.7

These are associations. They tell us a diverse, well-stocked gut tends to go with better health, not that any one supplement creates it.

Strain count isn't gut diversity

A probiotic with 60 strains doesn't add 60 permanent residents to your gut. Most probiotic strains lose some viability on the way through, meet resistance from the bacteria already there, and don't settle in long term.5 That's why daily use matters, and why a strain count is a design choice rather than a measure of your microbiome.

65 trials

and 10,863 people: in most cases, single strains were as effective as mixtures2

12 of 16

head-to-head comparisons favored the mixture, possibly because of higher total dose3

228 trials

showing probiotic effects are strain-specific and condition-specific8

Mixtures vs. single strains

This is the heart of the question, and the evidence is mixed:

  • The largest head-to-head review matched single strains against mixtures containing the same strain, across 65 trials. In most cases they were equivalent. A mixture did better for one use, and a single strain did better for another. The author's conclusion: choose by trial evidence, not by the number of strains.2
  • An earlier review found only 16 studies that compared a mixture with its own component strains, and the mixture did better in 12. The authors noted that mixtures were sometimes given at a higher total dose, which could explain the edge.3
  • The case for synergy is that strains may support each other, and multi-strain products have been studied for gut comfort and immune support. How that synergy works at the molecular level is still largely unknown.9

So why do we make 60- and 100-strain formulas?

Because effects are strain-specific and condition-specific,8 a broad daily probiotic is a bet on breadth. Different Lactobacillus and Bifidobacterium strains have been studied for different things, from regularity to immune support, and a diverse formula puts more of them in one capsule.* Some groups also help feed others: bifidobacteria break down fibers and cross-feed the colon bacteria that make butyrate, a key fuel for colon cells.10

What diversity doesn't do is replace targeting. If you have a specific concern, a formula built around strains studied for it, at a potency guaranteed through expiration, is the better starting point. That's why our line includes both broad daily formulas and targeted ones.

How to judge a multi-strain probiotic

  • Named strains with research behind them, not just species names.8
  • Potency guaranteed through expiration, not only at manufacture.
  • Delivery built for stomach acid. Most commercial forms offered strains little protection in simulated stomach juice unless they had strong enteric protection.11
  • Diversity as a bonus, not the headline. A high strain count is useful breadth, not proof of results.

Our probiotic buying guide covers these criteria in more depth.

High-diversity daily formulas

60
strainsVital Flora Ultra Daily Probiotic, shelf-stable

Ultra Daily | Vital Flora

60B cultures, 60 strains, 7 organic prebiotics

A balanced 30B Lacto + 30B Bifido blend in a delayed-release capsule, for everyday digestive and immune support.*

Shop Ultra Daily
100
strainsVital Flora Advanced Biome Probiotic

Advanced Biome | Vital Flora

100B cultures, 100 strains, 10 organic prebiotics

Our most diverse, highest-potency formula, in a delayed-release capsule, shelf-stable or refrigerated.*

Shop Advanced Biome

Want to understand the numbers? Our CFU guide covers potency, and our guide to constipation strains shows how targeted strains compare.

Frequently asked questions

No. Across 65 trials, multi-strain mixtures were usually no more effective than a matched single strain for the same condition.2 What a broad formula offers is breadth: more strains studied for different things in one capsule.* For a specific concern, the right named strains matter more than the total count.

Many are built around one or a few well-studied strains at a known dose, which makes sense for a targeted goal. A broad formula takes a different approach, favoring range across many strains. Both can be good products; the question is which fits what you want.

The limited direct evidence doesn't suggest mixtures work worse. In one review, mixtures did better than their own component strains in 12 of 16 comparisons, though higher total doses may explain part of that.3 Researchers think strains may support each other, but how is still largely unknown.9

You can't tell from symptoms alone. Gut diversity is measured by sequencing a stool sample, and even then, what counts as healthy varies from person to person.4 A varied, fiber-rich diet feeds a wider range of gut bacteria, and a daily probiotic can support that balance.* If you have ongoing digestive symptoms, talk to your healthcare provider.

They measure different things. CFU tells you how many live bacteria are in a serving; strain count tells you how many different types. Neither guarantees results on its own, since effects depend on the specific strains and your goal.8 Our CFU guide covers the dose research.

For digestive goals, give it about four weeks of daily use. Because most strains don't settle in permanently, consistency matters more than anything else.5 See how long probiotics take to work.

Written by the Vital Planet team.

References

  1. Tap J, et al. Identification of an Intestinal Microbiota Signature Associated With Severity of Irritable Bowel Syndrome. Gastroenterology. 2017;152(1):111-123.e8. PubMed
  2. McFarland LV. Efficacy of Single-Strain Probiotics Versus Multi-Strain Mixtures: Systematic Review of Strain and Disease Specificity. Dig Dis Sci. 2021;66(3):694-704. PubMed
  3. Chapman CM, et al. Health benefits of probiotics: are mixtures more effective than single strains? Eur J Nutr. 2011;50(1):1-17. PubMed
  4. Lozupone CA, et al. Diversity, stability and resilience of the human gut microbiota. Nature. 2012;489(7415):220-30. PubMed
  5. Han S, et al. Probiotic Gastrointestinal Transit and Colonization After Oral Administration: A Long Journey. Front Cell Infect Microbiol. 2021;11:609722. PubMed
  6. Biagi E, et al. Gut Microbiota and Extreme Longevity. Curr Biol. 2016;26(11):1480-5. PubMed
  7. Duvallet C, et al. Meta-analysis of gut microbiome studies identifies disease-specific and shared responses. Nat Commun. 2017;8(1):1784. PubMed
  8. McFarland LV, et al. Strain-Specificity and Disease-Specificity of Probiotic Efficacy: A Systematic Review and Meta-Analysis. Front Med (Lausanne). 2018;5:124. PubMed
  9. Kwoji ID, et al. Multi-Strain Probiotics: Synergy among Isolates Enhances Biological Activities. Biology (Basel). 2021;10(4). PubMed
  10. Rivière A, et al. Bifidobacteria and Butyrate-Producing Colon Bacteria: Importance and Strategies for Their Stimulation in the Human Gut. Front Microbiol. 2016;7:979. PubMed
  11. Caillard R, Lapointe N. In vitro gastric survival of commercially available probiotic strains and oral dosage forms. Int J Pharm. 2017;519(1-2):125-127. PubMed
*These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure, or prevent any disease. Consult your healthcare provider before starting any supplement.
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