More probiotic strains the better? The surprising truth

R.Parnell (ANutr, MSc)

Walk into any health shop or scroll through supplement websites, and you’ll notice a common marketing message: “the more probiotic strains, the better.” But is this really true? Let’s explore what the science says.

The misconceptions: Why people think more strains must be better

It sounds logical - if one probiotic strain is beneficial, then combining ten or more should deliver even greater results. Many probiotic brands build on this idea, promoting “kitchen sink” formulas often without explaining the evidence behind each strain.

Another common assumption is that the more strains a probiotic contains, the more it will boost the diversity of your gut microbiome - but research doesn’t support this idea. While a diverse gut ecosystem is generally linked with better health, studies do not support the idea that taking probiotics with more strains is correlated to an increase in microbiome diversity or improvements in outcomes¹.

What actually matters in a probiotic supplement

In reality, probiotics are strain-specific, meaning the benefits of one strain can’t automatically be applied to another. A long list of strains on a label doesn’t guarantee better outcomes, especially if those strains have limited scientific evidence or haven’t been studied for your particular concern.

Another issue is dosage dilution. In supplements containing a high number of different strains, even clinically proven ones are often included at much lower doses. In contrast, products that focus on fewer, well-researched strains can deliver each at an effective, evidence-based dose which ultimately matters more than the total strain count¹.

The surprising truth

The best probiotic isn’t the one with the most strains; it’s the one with the right strains at the right dose, backed by clinical evidence for your health need.

So next time you compare products, look beyond the strain count. Check whether:

• The strains have been studied in humans for the outcome you care about. For example, Bifidobacterium lactis BB-12 has been shown to help increase bowel regularity², while Lactobacillus rhamnosus GG can decrease the risk of upper respiratory tract infections³.
• The dose of each strain matches the clinical research. Even the right strain won’t deliver results if the dose is too low. The strain must be provided at the level shown to be effective in clinical trials. Under-dosing is a common issue in multi-strain blends.
• The brand provides transparency about strain identity and quality standards.

Summary

Probiotics with 10+ strains might sound impressive, but it is not what determines whether a probiotic works. What really matters is the right bacterial strains, at the right dose, supported by clinical evidence.

High-strain blends often dilute the proven strains to ineffective levels, while focused formulas with fewer well-researched strains can often deliver stronger, more predictable results.

References

1. McFarland LV. Efficacy of Single-Strain Probiotics Versus Multi-Strain Mixtures: Systematic Review of Strain and Disease Specificity. Dig Dis Sci. 2021 Mar;66(3):694-704. doi: 10.1007/s10620-020-06244-z. Epub 2020 Apr 9. PMID: 32274669.

2. Eskesen D, Jespersen L, Michelsen B, Whorwell PJ, Müller-Lissner S, Morberg CM. Effect of the probiotic strain Bifidobacterium animalis subsp. lactis, BB-12®, on defecation frequency in healthy subjects with low defecation frequency and abdominal discomfort: a randomised, double-blind, placebo-controlled, parallel-group trial. Br J Nutr. 2015 Nov 28;114(10):1638-46. doi: 10.1017/S0007114515003347. Epub 2015 Sep 18. PMID: 26382580; PMCID: PMC4657032.

3. Hojsak I, Snovak N, Abdović S, Szajewska H, Misak Z, Kolacek S. Lactobacillus GG in the prevention of gastrointestinal and respiratory tract infections in children who attend day care centers: a randomized, double-blind, placebo-controlled trial. Clin Nutr. 2010 Jun;29(3):312-6. doi: 10.1016/j.clnu.2009.09.008. Epub 2009 Nov 5. PMID: 19896252.