Probiotic Strain Comparison Chart

Medical Disclaimer: This article is for informational purposes only and does not constitute medical advice. Probiotic effects are strain-specific and individual responses vary. Consult a healthcare provider before starting any probiotic supplement, especially if you are immunocompromised, critically ill, or taking medications.

Introduction

Not all probiotics are created equal. The health effects of probiotics are strain-specific, meaning that two organisms within the same species can produce entirely different clinical outcomes.^[1] Yet most consumers choose probiotics based on brand name or CFU count alone, without considering whether the specific strains in a product have evidence for their health goals.

This guide provides a comprehensive strain comparison chart to help you identify which probiotic strains have the best evidence for specific conditions — from digestive health to immune support to mental wellbeing.

How to Read This Chart

Each probiotic organism is classified by genus, species, and strain designation. For example, in Lactobacillus rhamnosus GG:

• Genus: Lactobacillus
• Species: rhamnosus
• Strain: GG

The strain designation matters most for clinical evidence. A product listing only "Lactobacillus rhamnosus" without a strain code may not deliver the same benefits as a product containing the well-studied GG strain.

Note on nomenclature: Several Lactobacillus species have been reclassified. L. rhamnosus is now Lacticaseibacillus rhamnosus, L. casei is now Lacticaseibacillus casei, and L. plantarum is now Lactiplantibacillus plantarum. We use the traditional names here for familiarity, with the understanding that product labels may reflect updated taxonomy.

Comprehensive Probiotic Strain Comparison Chart

Lactobacillus (and Reclassified) Strains

Strain	Key Benefits	Best For	Evidence Level	Learn More
L. rhamnosus GG (LGG)	Prevents antibiotic-associated diarrhea, supports immune function, reduces acute diarrhea duration	Diarrhea prevention, pediatric gut health, immune support	Strong — hundreds of RCTs	L. rhamnosus
L. rhamnosus HN001	May reduce eczema risk in infants, supports maternal mental health	Eczema prevention, pregnancy/postpartum	Moderate	L. rhamnosus
L. acidophilus NCFM	Reduces lactose intolerance symptoms, supports vaginal health, immune modulation	Lactose intolerance, general digestive health	Moderate	L. acidophilus
L. acidophilus La-5	Improves stool frequency, supports cholesterol metabolism	Constipation, cardiovascular health	Moderate	L. acidophilus
L. casei Shirota	May improve mood and reduce anxiety, supports bowel regularity	Mood, constipation, immune support	Moderate	L. casei
L. casei DN-114 001	Reduces antibiotic-associated diarrhea, supports immune function in elderly	Antibiotic-associated diarrhea, elderly immune health	Moderate	L. casei
L. plantarum 299v	Reduces IBS symptoms (bloating, pain), supports iron absorption	IBS, bloating, iron deficiency	Moderate	—
L. reuteri DSM 17938	Reduces infant colic crying time, supports gut motility	Infant colic, functional GI disorders	Strong (pediatric)	—
L. helveticus R0052	Reduces anxiety and depression scores (combined with B. longum R0175), lowers cortisol	Mental health, stress, gut-brain axis	Moderate	—

Bifidobacterium Strains

Strain	Key Benefits	Best For	Evidence Level	Learn More
B. longum BB536	Supports immune function, reduces allergy symptoms, improves bowel regularity	Allergies, constipation, elderly health	Moderate	B. longum
B. longum R0175	Reduces stress and anxiety (with L. helveticus R0052), supports gut-brain axis	Mental health, stress resilience	Moderate	B. longum
B. longum 35624	Reduces IBS symptoms, modulates immune response	IBS (all subtypes), immune regulation	Moderate–Strong	B. longum
B. bifidum Rosell-71	Supports gut barrier integrity, reduces cold and flu duration	Immune support, upper respiratory infections	Moderate	B. bifidum
B. adolescentis	Produces folate, supports fiber fermentation, associated with healthy aging	General microbiome diversity, metabolic health	Emerging	B. adolescentis
B. animalis subsp. lactis BB-12	Improves bowel regularity, supports immune function, well-studied in infants	Constipation, pediatric health, immune support	Strong	—
B. animalis subsp. lactis HN019	Reduces constipation and bloating, supports immune function in elderly	Functional constipation, elderly gut health	Moderate	—

Saccharomyces Strains

Strain	Key Benefits	Best For	Evidence Level	Learn More
S. boulardii CNCM I-745	Prevents antibiotic-associated diarrhea, reduces C. difficile recurrence, treats acute diarrhea	Antibiotic-associated diarrhea, traveler's diarrhea, C. difficile	Strong — extensive meta-analyses	S. boulardii

Bacillus (Spore-Forming) Strains

Strain	Key Benefits	Best For	Evidence Level	Learn More
B. coagulans GBI-30, 6086	Reduces IBS symptoms, improves protein digestion, shelf-stable	IBS, digestive comfort, sports nutrition	Moderate	—
B. subtilis DE111	Supports immune function, improves lipid profiles, shelf-stable	General wellness, immune support	Emerging	B. subtilis
B. clausii O/C, SIN, N/R, T	Used widely in European and Asian medicine for diarrhea, antibiotic recovery	Acute diarrhea, antibiotic recovery	Moderate (regional)	—

Key Principles for Choosing a Probiotic

1. Match the Strain to Your Goal

The most common mistake is choosing a probiotic based on generic claims rather than strain-specific evidence. If you are managing IBS, look for strains with IBS trial data (such as B. longum 35624 or L. plantarum 299v).^[4] If preventing antibiotic-associated diarrhea, S. boulardii CNCM I-745 or L. rhamnosus GG have the strongest evidence.^[2,3]

2. Verify the Strain Designation on the Label

A quality probiotic product should list the full strain designation — not just genus and species. If a label says only "Lactobacillus acidophilus" without a strain code, you cannot verify whether it matches strains used in clinical research.^[7]

3. CFU Count Is Not Everything

Higher CFU counts do not necessarily mean greater efficacy. Most clinical trials use doses ranging from 1 billion to 100 billion CFU, and the effective dose varies by strain. L. rhamnosus GG is effective at 10 billion CFU for diarrhea prevention, while some Bifidobacterium strains show benefits at 1 billion CFU. See our CFU guide for more details.

4. Consider Delivery and Stability

Some strains require refrigeration (many Lactobacillus and Bifidobacterium strains), while spore-forming strains (Bacillus species) and yeast-based probiotics (Saccharomyces boulardii) are shelf-stable. Enteric coating or delayed-release capsules may improve survival through stomach acid, though not all strains require this protection.

5. Duration Matters

Most clinical trials show benefits after 4–8 weeks of daily use. Probiotic effects generally do not persist after discontinuation, as supplemented strains typically do not permanently colonize the gut.^[7] Ongoing use may be necessary for sustained benefits.

Strains by Health Goal: Quick Reference

Antibiotic-associated diarrhea: S. boulardii CNCM I-745, L. rhamnosus GG

IBS: B. longum 35624, L. plantarum 299v, B. coagulans GBI-30 6086

Constipation: B. animalis subsp. lactis BB-12, B. animalis subsp. lactis HN019, L. casei Shirota

Mental health and stress: L. helveticus R0052 + B. longum R0175, L. casei Shirota

Immune support: L. rhamnosus GG, B. animalis subsp. lactis BB-12, B. bifidum Rosell-71

Infant colic: L. reuteri DSM 17938

Eczema prevention: L. rhamnosus HN001

Limitations and Caveats

Probiotic research has important limitations. Many studies are small, industry-funded, and vary in quality.^[7] Effects observed in one population may not generalize to another. Individual responses depend on the person's existing microbiome, diet, genetics, and health status. What works for one person may not work for another.

Additionally, the probiotic field is evolving rapidly. Next-generation probiotics like Akkermansia muciniphila and Faecalibacterium prausnitzii are showing promise in early research but are not yet widely available as supplements.

The Bottom Line

Choosing the right probiotic means looking beyond the brand and the billion-CFU headline to focus on the specific strain and its evidence base for your health goal. The comparison chart above provides a starting point, but always discuss probiotic use with a healthcare provider — especially if you have underlying health conditions or take medications.

References

1. Hill C, Guarner F, Reid G, et al. The International Scientific Association for Probiotics and Prebiotics consensus statement on the scope and appropriate use of the term probiotic. Nat Rev Gastroenterol Hepatol. 2014;11(8):506-514.
2. McFarland LV. Systematic review and meta-analysis of Saccharomyces boulardii in adult patients. World J Gastroenterol. 2010;16(18):2202-2222.
3. Goldenberg JZ, Yap C, Lytvyn L, et al. Probiotics for the prevention of Clostridium difficile-associated diarrhea in adults and children. Cochrane Database Syst Rev. 2017;12:CD006095.
4. Ford AC, Quigley EMM, Lacy BE, et al. Efficacy of prebiotics, probiotics, and synbiotics in irritable bowel syndrome. Am J Gastroenterol. 2014;109(10):1547-1561.
5. Sanders ME, Merenstein DJ, Ouwehand AC, et al. Probiotic use in at-risk populations. J Am Pharm Assoc. 2016;56(6):680-686.
6. Dimidi E, Christodoulides S, Fragkos KC, et al. The effect of probiotics on functional constipation in adults. Am J Clin Nutr. 2014;100(4):1075-1084.
7. Suez J, Zmora N, Segal E, Elinav E. The pros, cons, and many unknowns of probiotics. Nat Med. 2019;25(5):716-729.