What Is Lactobacillus Salivarius (Ligilactobacillus Salivarius)?

Lactobacillus salivarius is a Gram-positive, rod-shaped, non-spore-forming bacterium that belongs to the lactic acid bacteria family. It was first formally described and named in 1953 by Rogosa and colleagues, who isolated it from human saliva.^[1] For nearly 70 years, it lived under the Lactobacillus umbrella alongside dozens of other species—until a sweeping 2020 taxonomic reclassification reorganized the genus into 23 new genera. Lactobacillus salivarius was reassigned to the new genus Ligilactobacillus, giving it the formal name Ligilactobacillus salivarius.^[1]

You'll still see both names used interchangeably in literature, supplement labeling, and clinical practice—the organism is the same regardless of which nomenclature is applied. The name Ligilactobacillus reflects the genus's host-adapted lifestyle, with strains typically specialized to colonize vertebrate gastrointestinal environments.

Where It Lives in Your Body

What distinguishes L. salivarius from many other probiotic species is its range. While strains like Bifidobacterium longum are primarily associated with the colon, L. salivarius inhabits the entire oropharyngeal-gastrointestinal tract—the mouth, pharynx, esophagus, small intestine, and large intestine.^[1] Concentrations tend to be highest in the small intestine and saliva, which directly informs some of its most clinically studied applications.

This broad colonization range is supported by several properties that make L. salivarius unusually resilient:

• Acid tolerance: Most strains demonstrate strong survival at low pH levels, allowing them to pass through gastric conditions with high viability.^[1]
• Bile salt resistance: Effective colonization of the small intestine requires surviving the high concentrations of bile acids that would destroy less robust organisms—a property that makes L. salivarius particularly effective in upper intestinal environments where bile acid concentrations peak shortly after meals.
• Mucosa adhesion: L. salivarius expresses surface proteins that allow it to adhere directly to intestinal epithelial cells and mucosal surfaces—a critical factor in its ability to provide sustained benefit rather than transient passage.^[1]

Natural Sources of Lactobacillus Salivarius

As a lactic acid bacteria, L. salivarius occurs naturally in several fermented foods—though the specific strains present in food products vary widely and may differ from the clinical strains studied in research. Yogurt, kefir, certain aged cheeses, fermented vegetables like sauerkraut, and other traditionally fermented dairy products can contain L. salivarius alongside other Lactobacillus species. That said, concentrations in food are typically lower and less consistent than what's delivered in a targeted probiotic supplement, and the strain identity in whole foods is rarely confirmed at the species level, let alone the strain level. Supplementation remains the most reliable way to deliver a documented strain at a clinically meaningful CFU dose.

Lactobacillus Salivarius Benefits: Evidence from Clinical Research

The research on L. salivarius spans multiple organ systems—which makes sense given how broadly it colonizes the human body. Below is an honest summary of what the evidence actually shows, grounded in peer-reviewed human clinical trials and systematic reviews.

1. Oral Health: Halitosis, Periodontal Disease, and Dental Caries

This is where some of the strongest and most consistent clinical evidence for L. salivarius exists. Because the strain is a natural inhabitant of the oral cavity, researchers recognized early that it might outcompete odor-producing anaerobic bacteria in the saliva and subgingival pockets.

Within the broader category of oral probiotics—probiotic strains specifically studied for their effects in the mouth, gums, and upper respiratory tract—L. salivarius is among the most extensively characterized. It is sometimes compared to Streptococcus salivarius K12, another well-studied oral probiotic associated with ear, nose, and throat health. While both colonize the oral cavity, L. salivarius distinguishes itself through its broader anatomical range, its clinically documented effects on periodontal disease, and its capacity to colonize and benefit the full gastrointestinal tract—making it a more versatile probiotic strain for systemic health support alongside oral applications.

An open-label clinical trial by Iwamoto and colleagues gave 20 patients with halitosis 2.0 × 10⁹ CFU of L. salivarius WB21 daily in tablet form for four weeks. Oral malodor parameters decreased significantly at the two-week mark in patients with physiologic halitosis, and organoleptic test scores—a clinician's direct assessment of breath odor—improved by week four. Researchers also observed reductions in bleeding on probing from the periodontal pocket.^[3]

A larger randomized, double-blind, placebo-controlled study by Shimauchi et al. enrolled 66 healthy volunteers and administered L. salivarius WB21 (6.7 × 10⁸ CFU) three times daily for eight weeks. At the end of the trial, the probiotic group demonstrated measurable improvements in periodontal clinical parameters compared to placebo. A separate RCT by Mayanagi and colleagues using the same strain found reduced populations of periodontopathic bacteria in both supragingival and subgingival plaque samples, detected via quantitative real-time PCR.^[5][4]

A 2020 randomized phase II trial tested L. salivarius G60 alone and combined with a prebiotic (inulin) in patients with oral halitosis and tongue coating. The synbiotic group—probiotic plus prebiotic—showed significantly greater reductions in halitosis measured by Halimeter compared to placebo, and the combination also improved quality of life scores.^[12] This synergistic finding is relevant when considering probiotic formulations that include prebiotic support alongside the bacterial strains.

On the caries front, a randomized open-label clinical trial by Nishihara et al. found that tablets containing L. salivarius WB21 and TI2711 modified plaque acidogenicity and microbiological parameters over the treatment period, though results on mutans streptococci were variable among participants—a useful reminder that oral microbiome responses are individualized.^[11]

2. Atopic Dermatitis and Skin Health

One of the more compelling bodies of clinical evidence around L. salivarius concerns the strain LS01 (also designated DSM 22775) and its effects on atopic dermatitis (AD)—a chronic inflammatory skin condition characterized by eczema, pruritus, and compromised skin barrier function.

A double-blind, randomized, placebo-controlled study by Drago and colleagues treated 38 adults with moderate-to-severe AD using L. salivarius LS01 or placebo (maltodextrin) for 16 weeks. Patients in the probiotic group demonstrated statistically significant improvement in SCORAD index (a validated clinical scoring tool for AD severity) compared to the placebo group, with p < 0.0001. Dermatology Life Quality Index (DLQI) scores also improved significantly (p = 0.021). Importantly, fecal analysis showed a notable reduction in staphylococci—bacteria strongly associated with AD flares—in the probiotic group.^[6]

A follow-up study by the same research group examined the microbiological and immunological changes in more detail. The L. salivarius LS01 group showed a shift in cytokine production—specifically, the strain appeared to help rebalance dysregulated Th1/Th2 immune responses that are characteristic of AD, reducing Th2-skewing without suppressing overall immune competence.^[7]

A third study extended these findings to a pediatric population: 43 children aged 0–11 years with AD were treated with L. salivarius LS01. Clinical parameters—SCORAD and itch index—showed significant improvement from baseline in the probiotic-treated group.^[8]

A 2022 systematic review and network meta-analysis examining probiotic interventions for adult AD ranked the combination of L. salivarius LS01 with a Bifidobacterium strain as having the highest probability of being the best supplementation option (SUCRA 95.2%) across both short-term and long-term outcomes.^[13] Bifidobacterium breve—another strain included in MicroBiome Restore—was also highlighted in this analysis.

3. Immune System Modulation and Broader Inflammatory Conditions

Beyond skin-specific outcomes, L. salivarius has been studied for its broader immunomodulatory effects. A comprehensive review of the strain's applications noted clinical use across conditions including asthma, cancer-supportive contexts, atopic dermatitis, and halitosis—with the strongest evidence in the latter two categories.^[2] Research demonstrates that different L. salivarius strains can shift cytokine production in both pro- and anti-inflammatory directions depending on the immune context—an important distinction that separates it from less nuanced immune interventions.^[9]

A 2023 Frontiers in Microbiology study by Carbonne and colleagues characterized a newer strain, Ligilactobacillus salivarius CNCM I-4866, in a murine colitis model and found that treatment reduced key pro-inflammatory markers—IL-1β, TNF-α, and IL-12—while upregulating anti-inflammatory IL-10. In epithelial cell assays, the strain also reduced IL-8 secretion following inflammatory challenge, and showed capacity to restore intestinal permeability markers.^[9]

This type of regulatory, context-dependent immune modulation—rather than blanket suppression or stimulation—is consistent with what researchers describe as a "tolerance-inducing" probiotic phenotype, where the organism helps train the immune system toward more balanced responses without compromising its ability to fight genuine pathogens.

4. Physical Performance and Fatigue Reduction

An emerging and somewhat surprising area of L. salivarius research concerns exercise performance. A study examining L. salivarius subspecies salicinius SA-03—isolated from the gut microbiota of a 2008 Olympic gold medalist—found that four weeks of supplementation in mice significantly improved muscle strength and endurance, increased glycogen storage in the liver and muscle, and reduced lactate, blood urea nitrogen (BUN), ammonia, and creatine kinase levels following exercise.^[10]

While this research is preclinical and should be interpreted cautiously in human contexts, it opens an interesting discussion about the gut-muscle axis and how probiotic composition may influence physical recovery—an area of growing scientific interest for athletes and active individuals.

How L. Salivarius Works: Mechanisms Behind the Benefits

Understanding why L. salivarius produces the effects documented in clinical trials requires looking at the mechanistic level—how it interacts with host cells, immune pathways, and the broader microbial ecosystem. Unlike less-studied probiotic species, L. salivarius has been characterized extensively at the genomic, proteomic, and cellular levels, giving researchers a clearer picture of its functional toolkit.^[1]

Adhesion to the Intestinal Mucosa

For a probiotic to produce sustained benefits—rather than transient effects that disappear within days of stopping supplementation—it must be able to colonize the gut lining rather than simply pass through. L. salivarius expresses surface proteins that mediate adhesion to intestinal epithelial cells, allowing it to physically establish a foothold on mucosal surfaces. Research on strain UCC118 specifically identified sortase-anchored surface proteins as key mediators of this adhesion and showed that disrupting this mechanism reduced the strain's ability to modulate intestinal epithelial gene expression.^[1]

Adhesion is also the first step in competitive exclusion: by occupying attachment sites on the epithelium, L. salivarius prevents pathogenic organisms from accessing those same sites—a straightforward but highly effective antimicrobial strategy that doesn't require antibiotic-like mechanisms.

Bacteriocin Production and Antimicrobial Activity

One of the most pharmacologically relevant features of L. salivarius is its antimicrobial activity—specifically its capacity to produce bacteriocins, which are antimicrobial peptides that target specific microbial species without disrupting the broader commensal community. This targeted antimicrobial activity is one of the primary mechanisms that distinguishes probiotic strains from conventional antibiotics: bacteriocins create selective pressure against pathogens while leaving beneficial organisms largely intact. The specific bacteriocins produced by individual L. salivarius strains vary considerably based on their plasmid composition, but multiple strains have demonstrated inhibitory activity against pathogens including Listeria monocytogenes, Staphylococcus aureus, Porphyromonas gingivalis, Prevotella intermedia, and Aggregatibacter actinomycetemcomitans—the last three being key drivers of periodontal disease and oral halitosis.^[1]

The bacteriocin-producing capacity of L. salivarius partly explains why its oral health benefits have been among the most consistently demonstrated in clinical trials: the strain is capable of directly eliminating the organisms responsible for VSC production and gingival inflammation.

Immune Pathway Modulation

L. salivarius interacts with the immune system primarily through pattern recognition receptors—specifically Toll-Like Receptor 2 (TLR2) and TLR4. Research demonstrates that L. salivarius B1 upregulates TLR2 expression in intestinal tissues, which stimulates maturation of the mucosal immune system and increases IgA-producing cell populations.^[2] Elevated secretory IgA (sIgA) is associated with stronger mucosal immunity and reduced susceptibility to enteric infections.

At the cytokine level, L. salivarius exposure has been shown to influence NF-κB signaling—a central pathway in inflammation regulation. Studies on strain UCC118 found that exposure to intestinal epithelial cells upregulated genes encoding negative regulators of NF-κB (TNFAIP3, NFKBIA, BIRC3), effectively dialing down inflammatory signaling cascades without eliminating immune responsiveness.^[1]

Antioxidant Activity

Emerging research highlights the antioxidant potential of L. salivarius strains. A study by Zhang and colleagues found that L. salivarius M18-6 activated the Keap1-Nrf2 pathway and the thioredoxin system—two of the body's primary endogenous antioxidant defenses—in the context of alcohol-induced injury.^[1] Nrf2 pathway activation upregulates production of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT), helping neutralize reactive oxygen species that contribute to cellular and tissue damage.

These antioxidant properties are particularly relevant in the context of gut inflammation, where oxidative stress is both a cause and consequence of mucosal damage, and in systemic inflammatory conditions like atopic dermatitis.

Lactobacillus Salivarius and Your Gut Microbiome

No probiotic strain operates in isolation. Understanding L. salivarius's role in the broader gut microbiota—and how it interacts with the other organisms that make up your intestinal flora—is essential for appreciating why it belongs in a comprehensive, multi-strain formulation rather than as a standalone supplement.

If you've noticed signs of Lactobacillus deficiency—including digestive irregularity, bloating, increased susceptibility to infections, or changes in skin health—L. salivarius may be one of the specific beneficial bacteria your intestinal flora is lacking. Its presence is associated with a balanced microbial landscape, and its absence—common after antibiotic use, poor diet, or chronic stress—can create ecological niches that allow opportunistic pathogens to expand.

Synergistic Action with Bifidobacterium Species

The network meta-analysis on atopic dermatitis mentioned earlier found that L. salivarius LS01 combined with a Bifidobacterium strain outperformed either alone—suggesting genuine microbiome-level synergy between these two genera.^[13] MicroBiome Restore includes five Bifidobacterium species (B. bifidum, B. breve, B. infantis, B. lactis, and B. longum subsp. longum) alongside L. salivarius, mirroring the kind of multi-genus approach that research increasingly supports over single-strain supplementation.

This matters because the gut microbiota functions as an ecosystem: individual species influence the metabolic outputs and population dynamics of others through substrate competition, cross-feeding relationships, and the production of metabolites like short-chain fatty acids (SCFAs). When beneficial bacteria like L. salivarius and Bifidobacterium species coexist in the intestinal flora, they tend to reinforce each other's colonization and metabolic activity. A formulation that delivers both L. salivarius and complementary Bifidobacterium species is working with this ecology rather than against it. Learn more about how multi-strain probiotic formulas can support a more balanced gut ecosystem.

How L. Salivarius Contributes to Gut Barrier Integrity

Research on L. salivarius CNCM I-4866 found that the strain not only reduced colonic inflammation markers but also helped restore intestinal permeability—a key function of the intestinal barrier that is frequently compromised in individuals with IBD, food sensitivities, or chronic stress.^[9] At the structural level, the intestinal barrier is maintained largely by tight junction proteins—specialized protein complexes including occludin, claudins, and ZO-1 that seal the spaces between adjacent epithelial cells. When these tight junction proteins are disrupted by inflammation, pathogenic bacteria, or oxidative stress, the result is increased gut permeability (colloquially called "leaky gut"), which allows bacterial products to translocate into systemic circulation. By supporting tight junction protein expression and reducing pro-inflammatory cytokine signaling that degrades these structures, L. salivarius contributes to maintaining this barrier function—the structural and immunological scaffolding that keeps intestinal contents where they belong. If you're specifically focused on gut barrier repair, understanding which strains support tight junction integrity is important context.

The Role of Prebiotics: Synbiotic Amplification

The halitosis trial by Mousquer et al. found that combining L. salivarius G60 with a prebiotic (inulin) produced significantly greater reductions in halitosis than the probiotic alone—a classic demonstration of the synbiotic principle.^[12] Prebiotics provide fermentable substrate that supports probiotic colonization and metabolic activity, and the combination of the two has been repeatedly shown to outperform either component in isolation.

MicroBiome Restore is formulated as a genuine synbiotic: alongside its 26 probiotic strains, it provides 9 organic prebiotics including Jerusalem artichoke, maitake mushroom, fig fruit, bladderwrack, Norwegian kelp, oarweed, and acacia. Each of these ingredients serves as fermentable fuel for the probiotic strains, including L. salivarius. The capsule material itself—pullulan—is a fermented prebiotic polysaccharide, which means the delivery vehicle is actively contributing to the prebiotic environment even before the capsule is fully dissolved.

L. Salivarius Alongside Other Lactobacillus Strains

L. salivarius works most effectively as part of a broader community of lactic acid bacteria and complementary probiotic genera. In MicroBiome Restore, it is joined by well-researched Lactobacillus species including L. acidophilus, L. rhamnosus, L. plantarum, L. gasseri, L. reuteri, L. casei, L. paracasei, L. fermentum, L. bulgaricus, L. buchneri, and Pediococcus species. Each of these beneficial bacteria contributes distinct mechanisms and colonizes different niches along the gastrointestinal tract, creating overlapping layers of protective and restorative function. For instance, Lactobacillus plantarum contributes its own well-documented anti-inflammatory and barrier-supporting properties, complementing L. salivarius's oral and immunomodulatory activity.

What to Look for in a Lactobacillus Salivarius Supplement

Understanding the research is one thing; translating that knowledge into a purchasing decision is another. Here's what the evidence and formulation science suggest you should actually pay attention to when evaluating a product that contains L. salivarius.

Dosage: What Clinical Trials Actually Used

Clinical trials on L. salivarius have used doses ranging from approximately 10⁸ to 10¹⁰ CFU per day, depending on the condition being studied and the specific strain. The oral health trials with WB21 used doses in the range of 6.7 × 10⁸ to 2.0 × 10⁹ CFU daily.^[4][5] The atopic dermatitis trials with LS01 typically used 10⁹ CFU or higher.^[6]

What this tells us is that effective doses are well within the range of commercially available probiotic supplements—but the CFU count is only meaningful if the organisms are viable at point of consumption. Shelf stability, manufacturing practices, and delivery mechanism all influence how many of those labeled CFUs actually reach their destination alive.

Safety Profile: What the Evidence Says

Across available clinical evidence—including studies in children as young as infants, adults with chronic inflammatory conditions, and healthy older adults—L. salivarius has demonstrated a consistent safety profile with no serious adverse events documented at typical probiotic doses.^[2] The most commonly observed side effects in published trials are mild and transient gastrointestinal symptoms (such as temporary bloating), typically resolving within the first week of supplementation as the microbiome adjusts.

The European Food Safety Authority (EFSA) has granted L. salivarius Qualified Presumption of Safety (QPS) status—the regulatory recognition that a microorganism has sufficient evidence to be considered safe for human use without extensive case-by-case evaluation. This distinguishes L. salivarius from more controversial supplement ingredients.

Formulation Quality: What Goes Into the Capsule Matters

L. salivarius's documented benefits can be meaningfully undermined by how the supplement is formulated. Several common excipients found in mainstream probiotic products have been shown to interfere with the gut microbiome—the very ecosystem a probiotic is intended to support.

Titanium dioxide (E171), a common whitening agent, has been shown to reduce populations of Bifidobacterium and Lactobacillus species—including the exact organisms you're trying to introduce.^[1] The EU banned its use as a food additive in 2022 after EFSA determined genotoxicity concerns could not be ruled out. Magnesium stearate, another common flow agent, has been shown to alter intestinal immune function. Microcrystalline cellulose (MCC), a ubiquitous bulking agent, carries its own emerging concerns around gut wall interaction.

Understanding what's in the "other ingredients" section of your supplement label is not optional if you're serious about gut health outcomes. Our guide to reading supplement labels walks through how to identify these additives and why they matter. Separately, our breakdown of fillers and flow agents in probiotics covers the industry-wide problem in detail.

Reviewing a product like MicroBiome Restore against these criteria: pullulan capsules (prebiotic, delayed release), zero titanium dioxide, zero MCC, zero magnesium stearate, 26 strains across six genera, and nine organic prebiotic sources. These aren't arbitrary differentiators—they reflect the principle that supplement formulation should support the goal of the product, not work against it.

If you're specifically evaluating probiotic options for different life stages or health contexts, our guides on the best probiotic strains for women over 40 and our overview of 10 probiotic strains for gut health provide broader context for evaluating how L. salivarius fits into a complete strategy.

Frequently Asked Questions

Conclusion: An Underappreciated Workhorse of the Probiotic World

Lactobacillus salivarius doesn't always make headlines the way some better-marketed probiotic strains do, but the body of peer-reviewed evidence behind it is substantial, well-characterized, and clinically meaningful. From randomized controlled trials demonstrating measurable improvements in halitosis and periodontal health, to double-blind studies showing significant atopic dermatitis score improvements, to in vitro and in vivo work illuminating how it regulates immune signaling and supports the gut barrier—this is a strain with serious scientific backing.

The key takeaway for anyone evaluating probiotic supplements is that strain identity, formulation quality, and multi-species context all matter enormously. A product that contains L. salivarius but packages it alongside titanium dioxide, microcrystalline cellulose, or magnesium stearate is working against its own stated purpose. And a product that delivers L. salivarius without complementary strains, prebiotic support, or a survivable delivery mechanism is likely leaving most of its potential unrealized.

At BioPhysics Essentials, we take the position that the science should drive the formulation—not manufacturing convenience or aesthetic appeal. That's why MicroBiome Restore combines L. salivarius with 25 other evidence-supported strains, 9 organic prebiotics, and 80+ trace minerals from organic sea vegetables, all in prebiotic pullulan capsules free of every filler and flow agent that could compromise what you're taking it for.